Ore-Forming Mechanisms of Vein-Type Fluorite Deposits in the Linxi District, Inner Mongolia, China

Ore-forming Mechanisms of Vein-type Fluorite Deposits in the Linxi District, Inner Mongolia, China

(中国内モンゴル自治区、リンシー地域の鉱脈型蛍石鉱床の形成機構)

July 2018

Qiuming PEI Ore-forming Mechanisms of Vein-type Fluorite Deposits in the Linxi District, Inner Mongolia, China

(中国内モンゴル自治区、リンシー地域の鉱脈型蛍石鉱床の形成機構)

A Dissertation Submitted to

the Graduate School of Life and Environmental Sciences,

the University of Tsukuba

in Partial Fulfillment of the Requirements

for the Degree of Doctor of Philosophy in Science

(Doctoral Program in Earth Evolution Sciences)

Qiuming PEI CONTENTS

CONTENTS ...... i Abstract ...... iii List of Figures ...... v List of Tables ...... viii Chapter 1: Regional tectonic evolution ...... 1 1 Introduction ...... 1 2 Geological setting ...... 3 3 Sampling and petrography ...... 5 4 Analytical methods ...... 8 4.1 Zircon U–Pb analyses ...... 8 4.2 Whole-rock geochemical analyses ...... 10 4.3 In situ zircon Hf isotopic analyses ...... 11 5 Analytical results ...... 12 5.1 Zircon U–Pb ages ...... 12 5.2 Whole-rock major and trace elements ...... 14 5.3 Zircon Hf Isotopes...... 19 6 Discussion ...... 20 6.1 Timing of magmatism in the Linxi area ...... 20 6.2 Genetic types ...... 22 6.3 Nature of the magma sources ...... 25 6.4 Tectonic interpretation and evolution ...... 27 7 Conclusions ...... 33 Chapter 2: Geochronology, geochemistry, fluid inclusion and C, O and Hf isotope compositions of the Shuitou fluorite deposit, Inner Mongolia, China ...... 34 1 Introduction ...... 34 2 Geologic Setting ...... 36 2.1 Regional Geology...... 36 2.2 Geology of the Shuitou deposit ...... 38 3 Sampling and analytical methods ...... 41 3.1 Major and trace elements ...... 42 3.2 Fluid Inclusions ...... 42 3.3 Zircon U–Pb geochronology and Lu–Hf isotopes ...... 43 3.4 Fluorite Sm–Nd analyses ...... 44 3.5 Stable isotopes (C–O) ...... 45 4 Analytical results ...... 46 4.1 Major, trace, and rare earth elements ...... 46 4.2 Zircon U–Pb Ages ...... 49 4.3 Zircon Hf Isotopes...... 50 4.4 Fluorite Sm and Nd Isotopic Compositions ...... 51 4.5 C–O Isotopic compositions ...... 52 4.6 Fluid inclusions ...... 52

i 5 Discussion ...... 54 5.1 Timing of magmatism and fluorite mineralization, and tectonic setting ...... 54 5.2 Nature and evolution of ore fluids...... 58 5.3 Mechanism of fluorite mineralization ...... 62 6 Conclusions ...... 65 Chapter 3: Nature and genesis of the Xiaobeigou fluorite deposit, Inner Mongolia, Northeast China: Evidence from fluid inclusions and stable isotopes ...... 67 1 Introduction ...... 67 2 Geological Setting ...... 68 3 Ore deposit geology ...... 71 3.1 Wall rocks and structures ...... 71 3.2 Mineralization and alteration ...... 74 3.3 Vertical zonation of the orebodies ...... 76 4 Samples and methodology ...... 78 5 Analytical results ...... 80 5.1 Mineral Geochemistry ...... 80 5.2 Fluid inclusions ...... 81 5.3 Hydrogen and oxygen isotopic systematics ...... 85 6 Discussion ...... 86 6.1 Nature and evolution of the ore-forming fluid ...... 86 6.2 Sources of the ore-forming fluids...... 89 6.3 Ore genesis and tectonic setting ...... 90 7 Conclusions ...... 91 Chapter 4: Conclusions ...... 93 Acknowledgements ...... 96 References ...... 98 Appendix I: Analytical data ...... 144

Abstract

The Linxi fluorite district is located in southern part of the Great Xing'an Range of

Northeast China and comprises a lot of fluorite deposits and occurrences such as

Shuitou, Xiaobeigou and Sandaoyingzi vein-type deposits. Tectonically, the study area is situated within the Xing’an-Mongolia segment of the Central Asian Orogenic Belt, which is known as one of the world’s largest sites of juvenile crustal growth in the

Phanerozoic era. Based on these new data and previous studies, tectonic evolution of the study area can be divided into four stages: (1) double-sided subduction of the Paleo-

Asian Ocean: (330–270 Ma); (2) the closure of the the Paleo-Asian Ocean and subsequent continent–continent collision: (270–237 Ma); (3) post-collisional extension:

(237–211 Ma); and (4) intracontinental extension (~150 Ma–~110 Ma).

The fluorite veins are mainly controlled by SN, NNE and NE-trending structures and commonly occur as sets of parallel and offset veins in steep faults and breccia zone.

The main ore-hosting rocks including volcanic-sedimentary rocks (Permian and

Jurassic) and granodiorites (Triassic) and granites (Jurassic). The ore-forming process in the deposit can be divided into hydrothermal period and supergene period, and the former period can be further divided into three stages: stage I, fluorite-quartz; stage II, quartz–fluorite; and stage III, quartz–sulfides–fluorite–calcite. Wall rock alterations are dominated by sets of medium-low temperature hydrothermal alterations.

The most common type of fluid inclusions hosted in fluorite and quartz is two- phase liquid-rich type. Homogenization temperatures of the fluid inclusions from

Shuitou and Xiaobeigou deposits vary from 140℃ to 240℃ and decrease from the

iii

early stage to the late stage. The calculated densities and salinities show the same decreasing trend and range from 0.86 to 0.891 g/cm3 and 0.27 to 2.8 wt.% NaCl eqv, respectively. Laser Raman spectra show that both the vapor and liquid compositions of

18 the inclusions are dominated by H2O. The δ O H2O-SMOW and δD H2O-SMOW values obtained from fluid inclusions in quartz and fluorite of the Shuitou and Xiaobeigou deposits range from -6.7‰ to +2.3‰ and -115.5‰ to -140.1‰, respectively. The

13 coexisting calcite from the Shuitou deposit has δ CV-PDB varying from -7.1‰ to -6.3‰

18 (average -6.73‰) and δ OV-SMOW from -2.8‰ to -0.7‰. The C-H-O isotopic features suggest that the ore-forming fluids consist dominantly of meteoric water. Thus, the ore- forming fluids can be mainly attributed to NaCl–H2O system with moderate to low temperature, low salinity and low density. Water/rock reaction is possibly the main mechanism of fluorite precipitation and crystallization.

The Sm-Nd isochron age of fluorites from Shuitou deposit are 132±11 Ma, and the calcites from the Sandaoyingzi deposit yield a Sm-Nd isochron age of 136.5±4.3 Ma, indicating that the major mineralization stage occurred during early Cretaceous (137–

132 Ma). The formation of the widespread fluorite vein systems in Linxi district is closely link to the period of tectonic transfer in northeast Asian which is characterized by the transformation from NNE-trending contraction to NNE-trending extension during the early Cretaceous. Subsequent regional extension and lithosphere thinning occurred, which triggered widespread fluorite mineralization in this region.

Key words：Fluorite deposit; Vein-type; Ore-forming mechanisms; Sm–Nd isotopic age; Late Mesozoic; Eastern China

List of Figures

Figure 1.1 a. Tectonic sketch map of the CAOB showing the location of the XMOB, and b. Simplified geological map of the XMOB…………………………………………………………………3 Figure 1.2 Sketch map showing the distribution of granitoids in the Linxi area, Inner Mongolia ……………………………………………………………….5 Figure 1.3 Representative photomicrographs showing the petrographical features of granitoids from the study area………………………………………….7 Figure 1.4 CL images of representative zircons from the Linxi granitoids………..9 Figure 1.5 Zircon U–Pb concordia diagrams and weighted mean 206Pb/238U ages for the (a and b) BSFZ pluton, (c) XNG pluton, (d) BS pluton, and (e) HD pluton. (f) Relative probability plot of zircon data from granitoids in the Linxi area and adjacent regions………………………………...……...14 Figure 1.6 Classification and series geochemical discrimination diagrams of the

Linxi granitoids: (a) QAP modal classification, (b) SiO2 versus ALK

diagram, (c) SiO2 versus K2O diagram, and (d) A/CNK versus A/NK diagram……………………………………………………………..…16 Figure 1.7 a. Chondrite-normalized REE, and b. N-MORB normalized trace element spider diagrams of the Linxi granitoids…………………………...17 Figure 1.8 a. Ages of zircons versus εHf (t) values diagram for the Linxi granitoids, b. histogram of zircon εHf (t) values of zircons, and c. histogram of the

two-stage Hf model ages (TDM2) ……………………………………...20 Figure 1.9 (a & b). Geochemical classification and (c & d) discrimination diagrams of the tectonic setting of the Linxi granitoids…………………………23

Figure 1.10 Plots of (a) P2O5 versus SiO2, (b) Pb versus SiO2, (c) Y versus Rb and (d) Th versus Rb for samples from the BSFZ and XNG plutons…………...24 Figure 1.11 Schematic diagrams showing the tectonic evolution of the XMOB…..28 Figure 2.1 (a) Simplified tectonic map of northeastern China, showing the location of southern Great Xing'an Range and the area of fluorite deposits

prospecting. (b) Sketch geological map of the SGXR, showing the distribution of mineral deposits in Late Mesozoic and regions rich in fluorite deposits………………………………………………………..36 Figure 2.2 Geological sketch map of the Shuitou fluorite deposit and morphological map within the north part of the study area based on WorldView-2 imagery………………………………………………………………..39 Figure 2.3 Field photographs of the Shuitou fluorite deposit…………………….42

Figure 2.4 Geochemical discrimination diagrams of (a) A/CNK vs. A/NK, (b) SiO2

vs. K2O for the Herimu Tai granite……………………………………47 Figure 2.5 Chondrite-normalized REE patterns and primitive mantle-normalized spider diagrams for the Herimu Tai granite …………………………..47 Figure 2.6 Geochemical classification of the Herimu Tai granite………………...48 Figure 2.7 Chondrite-normalized REE patterns for the calcite(a), quartz(b), fluorite (c) and wall rocks(d) from the Shuitou fluorite deposit……………….49 Figure 2.8 CL images of zircon (a), Zircon U–Pb concordia diagrams and weighted mean model ages (b) for the Herimu Tai granite………………………50 Figure 2.9 Ages of zircons vs. εHf (t) values diagram for the Late Mesozoic granitoids in the southern Great Xing'an Range……………………….51 Figure 2.10 Sm–Nd isochron of fluorites from the Shuitou deposit………………. .52 Figure 2.11 Laser Raman spectra of fluid inclusions within the fluorites from the Shuitou deposit………………………………………………………...54 Figure 2.12 Discrimination diagrams of tectonic setting of the Herimu Tai granite.56 Figure 2.13 Plot of Y/Ho vs. La/Ho for fluorite, calcite and quartz from the Shuitou deposit…………………………………………………………………60 Figure 2.14 Tb/Ca vs. Tb/La diagram for fluorite and calcite from Shuitou deposit60 Figure 2.15 δ18O versus δ13C diagram of calcites from the Shuitou deposit……….61 Figure 2.16 Schematic illustration depicting the ore-forming processes of Shuitou fluorite deposit, Inner Mongolia, China. a: Sketch map showing the tectonic setting at ca. 140-120 Ma. b: Suggested model for the fluorite deposit…………………………………………………………………65

Figure 3.1 (a) Tectonic sketch map of the Central Asian Orogenic Belt, showing the location of Northeast China; (b) tectonic subdivision of Northeast China; (c) simplified geological map of the South Great Xing'an Range.…………………………………………………………………69 Figure 3.2 (a) Geological map of the Xiaobeigou fluorite deposit; (b) rose diagram showing vein strike directions…………………………………………72 Figure 3.3 Photographs and photomicrographs of the main rocks and ore veins in the Xiaobeigou deposit. (a) Geological map of the Xiaobeigou fluorite deposit…………………………………………………………………73 Figure 3.4 Vertical zoning at the Xiaobeigou deposit…………………………….77 Figure 3.5 Illustration and photographs showing lateral zonation of fluorite mineralization in the central zone of the orebody.…………………….78 Figure 3.6 Chondrite-normalized REE patterns for the fluorite samples in the Xiao- beigou deposit..…………………………………………………. .81 Figure 3.7 Histograms of homogenization temperatures and salinities of the FIs from different stages...………………………………………………………83 Figure 3.8 Representative Raman spectra of the FIs in the Xiaobeigou deposit. (a) vapor phase and (b) liquid phase composition of L-type FIs in quartz; (c) vapor phase and (d) liquid phase composition of L-type FIs in late-stage fluorite. .……………………………………………………………….85 Figure 3.9 H-O isotopic compositions of the Xiaobeigou Deposit……………….86 Figure 3.10 Homogenization temperatures versus salinities for FIs from different stages…………………………………………………………………..87 Figure 3.11 Diagrams of (a) Y/Ho versus La/Ho and (b) Tb/Ca versus Tb/La for fluorite and quartz samples from the Xiaobeigou deposit…………….90

vii

List of Tables

Table 1.1 Descriptions of the four representative granitoid plutons in the Linxi area…………………………………………………………………….144 Table 1.2 LA-ICP-MS Zircon U-Pb isotope data for the Linxi granitoids………..145 Table 1.3 Geochemical data for the Linxi granitoids………………………………151 Table 1.4 Hf isotope data for zircons from the Linxi granitoids………………….155 Table 1.5 Zircon U–Pb ages of granitoids from the Linxi area and adjacent regions …………………………………………………………………………160 Table 2.1 Major (wt%) element compositions of the Herimu Tai granites at the shuitou fluorite deposit…………………………………………………………166 Table 2.2 Trace (ppm) element compositions of the Herimu Tai granites, fluorites, quartzs and calcites at the Shuitou fluorite deposit……………………..167 Table 2.3 Zircon U–Pb isotope data for the Herimu Tai granites………………….170 Table 2.4 Hf isotope data of zircons of Herimu Tai granites from the Shuitou fluorite deposit…………………………………………………………………..171 Table 2.5 Sm and Nd isotope compositions of fluorites from the Shuitou deposit..172

Table 2.6 Carbon and oxygen isotopic data of calcites from the Shuitou deposit…173 Table 2.7 Microthermometric data for fluid inclusions from the Shuitou fluorite

deposit………………………………………………………………….174 Table 3.1 Trace element compositions (ppm) of fluorite and quartz samples from the

Xiaobeigou fluorite deposit…………………………………………….175 Table 3.2 Microthermometric data for primary fluid inclusions in the Xiaobeigou

fluorite deposit………………………………………………………….178 Table 3.3 Hydrogen and oxygen isotopic compositions for the Xiaobeigou

deposit………………………………………………………………….179

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Chapter 1: Regional tectonic evolution

1 Introduction

The Central Asian Orogenic Belt (CAOB; Fig. 1.1a) or the Altaid Tectonic Collage, which is known as one of the world’s largest sites of juvenile crustal growth in the

Phanerozoic era (Jahn et al. 2004a; Jahn et al. 2000a; Şengör et al. 1993; Windley et al.

2007; Xu et al. 2015a; Yakubchuk 2004), has experienced a prolonged and complicated history of multiple accretion and arc-continent collision events since at least 1.0 Ga

(Jahn et al. 2000a; Li et al. 2013a; Xiao et al. 2015a). The southeastern segment of the

CAOB, which extends across Inner Mongolia, Heilongjiang, Jilin and Liaoning

Provinces in northern China, is called the Xing’an–Mongolia orogenic belt (XMOB,

Ren et al. 1980).

The complex orogenesis in the XMOB was driven by the closure of the Paleo-

Asian Ocean (PAO) and the Mongol–Okhotsk Ocean and subduction of the Paleo-

Pacific Plate (Xiao et al. 2012). Numerous fundamental problems remain unresolved, especially the timing and location of the final amalgamation of the PAO (Han et al.

2012; Jian et al. 2010; Li et al. 2013c; Liu et al. 2015; Song et al. 2015; Tong et al.

2015; Xiao et al. 2009; Zhao et al. 2017; Zhang et al. 2016b; Zhang et al. 2008a; Zhou et al. 2015a). Several EW- to ENE-trending subparallel ophiolite belts crop out in the

XMOB (Miao et al. 2008; Zhang et al. 2015b). The distribution of these ophiolites clearly shows a divergent trend from west to east (Fig. 1.1b), making determining both the precise location of the suture between the Siberia and North China cratons and the

timing of their final collision difficult. The Linxi area, which is located in the core region of the Solonker–Xar Moron suture (usually recognized as the major paleo-plate boundary; Eizenhöfer et al. 2014; Jian et al. 2010; Shi 2006; Wang and Liu 1986;

Windley et al. 2007; Xiao et al. 2003), is undoubtedly an important region for investigating the tectonic evolution of the XMOB.

Significantly, one of the distinctive characteristics of the XMOB is the massive distribution of Phanerozoic granitic intrusions (Fig. 1.1b; Wu et al. 2003; Wang et al.

2017; Wu et al. 2014; Wu et al. 2017), most of which were previously considered to have been emplaced during the Palaeozoic (IMBGMR 1991). In recent decades, extensive field investigations and precise geochronological data have revealed that the formation ages of a variety of granitoids include not only the Palaeozoic era but also the Mesozoic era (Cao et al. 2013; Guo et al. 2016; Ouyang et al. 2013; Wu et al. 2011a;

Yang et al. 2016a). Since granitoids are closely connected with tectonics and geodynamics (Bonin 2007), the study of granitoids in the Linxi area should provide important information and contribute to deciphering the multiple accretionary orogenic processes. Hence, I present new zircon U–Pb ages, whole-rock major and trace element compositions and Hf isotopes of representative samples from the Linxi area of the

XMOB. Moreover, combined with high-precision geochemical and age data of the regional igneous rocks, this work contributes to a better understanding on the reconstruction of the evolution history of the XMOB from the Late Palaeozoic to the

Mesozoic.

Fig. 1.1 (a) Tectonic sketch map of the CAOB showing the location of the XMOB, adopted from

Safonova and Santosh (2014). (b) Simplified geological map of the XMOB, modified from

IMBGMR (1991), Jian et al. (2010), Luo et al. (2016) and Zhang et al. (2016b). 2 Geological setting

The XMOB, which has an area of 1,600,000 km2, is located between the Siberia and North China cratons. It is composed of a series of Neoproterozoic to Mesozoic island arcs, oceanic islands, accretionary wedges, forearc or back-arc basins, ophiolites and some microcontinents (Khain et al. 2002; Xiao et al. 2012). These microcontinents are commonly rigid, and thus, they control the geometry of the intervening sutures (or folded zones) and even define the overall architecture of the entire belt to some degree

(Kröner et al. 2014).

Extensive research in the CAOB has resulted in several geological framework and tectonic models (see the discussion in Eizenhöfer et al. 2014 and Xu et al. 2015b).

These efforts have been dedicated to better understanding the tectonic development of the XMOB. The southeastern of XMOB, including the Linxi area and its adjacent

regions, can be simply divided from north to south into the Northern Accretionary

Orogen, the Solonker-Xar Moron suture zone and the Southern Accretionary Orogen

(Jian et al. 2008; Xiao et al. 2003).

The oldest known rocks in the Linxi area are Proterozoic metamorphic rocks of the

Baoyintu Formation (IMBGMR, 1991), including mica schists, plagioclase gneiss, chlorite-quartz schists and amphibolite (Chen et al. 2015), which are mainly exposed north of the Xar Moron River. Permian and Jurassic strata are widespread in the study area. The Permian strata comprise, from the bottom up, the Shoushangou, Dashizhai,

Zhesi and Linxi Formations, which are mainly composed of black slate, siltstone and sandstone. In contrast, the Jurassic strata are dominated by intermediate to acid lavas, lava breccia and tuffs interbedded with some sedimentary clastic rocks. Furthermore, the rocks in the region experienced very low-grade metamorphism at approximately

127 Ma, as revealed by a study of clay minerals (Hu et al. 2015).

During the Phanerozoic, the XMOB experienced a complex history that included several periods of accretion and collision, and it formed via the amalgamation of multiple terranes (Şengör et al. 1993; Xiao et al. 2015a). Voluminous magmatic rocks are exposed in the area and record multiple magmatic events. The granitoids can be classified into three broad groups: Early Palaeozoic, Late Palaeozoic and Mesozoic (Shi et al. 2014). Moreover, most of the Palaeozoic–Mesozoic granitoids show low initial

Sr isotopic ratios, positive εNd(t) values and young Nd model ages (Chen et al. 2000;

Hong et al. 2004; Jahn et al. 2000b), implying significant continental growth during the

Phanerozoic.

3 Sampling and petrography

The representative rock samples analysed in detail during this study were collected from four plutons in the central and western Linxi area, namely, the Banshifangzi

(BSFZ), Xinangou (XNG), Baoshan (BS) and Hada (HD) plutons, whose locations are shown in Fig. 1.2. It is worth noting that the boundaries between some plutons have not been accurately defined because of the considerable area of grasslands. The petrography of the representative samples is presented in Table 1.1.

Fig. 1.2 Sketch map showing the distribution of granitoids in the Linxi area, Inner Mongolia

(modified from Li et al. 2013b; Li et al. 2016b; Wu et al. 2011a). Published zircon U–Pb ages for granitoids in the region are given in Table 1.5.

The BSFZ pluton, which is located to the north of Banshifangzi Village, intruded into the Permian Linxi Formation and is overlain by late magmatic rocks and Cenozoic

sediments. The BSFZ pluton consists mainly of dark-grey granodiorite and granodiorite porphyry. The granodiorite is characterized by a fine-grained granitic texture and irregular mineral boundaries (Fig. 1.3A). The dominant minerals in the granodiorite are plagioclase (45–50 vol.%), quartz (approx. 30 vol.%), K-feldspar (approx. 15 vol.%), biotite (approx. 3 vol.%) and hornblende (approx. 2 vol.%), with sizes of 0.5–1.5 mm.

Accessory minerals include zircon, apatite, and titanite. The granodiorite porphyry is marked by a porphyritic texture. Petrographic observations show that phenocrysts, which are abundant in the granodiorite porphyry, range from 20–30 vol.% of the whole rock with typical grain sizes of 0.5–2 mm (Fig. 1.3B). The plagioclase phenocrysts display polysynthetic twinning with irregular boundaries (Fig. 1.3C). The mineral compositions mainly include plagioclase (45–50 vol.%), K-feldspar (approx. 20 vol.%), quartz (20–25 vol.%), biotite (2–5 vol.%) and hornblende (3–5 vol.%). Accessory minerals, such as zircon, titanite and magnetite, are also present.

The XNG pluton, which is located to the south of Xinangou Village, is predominantly light grey in colour with a fine-grained granitic texture and massive structure. The grain sizes of the monzogranite range from 200 μm to 1 mm in diameter.

The rock consists mainly of plagioclase (approx. 30 vol.%), K-feldspar (40–45 vol.%), and quartz (approx. 25 vol.%), accompanied by small amounts of biotite (approx. 3 vol.%) and accessory minerals (e.g., zircon, apatite and magnetite). K-feldspar crystals are mostly irregular and anhedral, and polysynthetic twinning is commonly observed in plagioclase (Fig. 1.3D).

Fig. 1.3 Representative photomicrographs showing the petrographical features of granitoids from the study area. Abbreviations: Bt, biotite; Kfs, potassium feldspar; Pl, plagioclase; and Q, quartz.

The BS pluton is located to the southwest of Yematu Village, and it intruded into

Permian muddy-sandy slates. It is mainly composed of charcoal-grey granite with a fine-grained granitic texture and a massive structure. The matrix mineral assemblage of the granite is composed of quartz (40–50 vol.%), K-feldspar (30–38 vol.%), plagioclase

(15–20 vol.%) and biotite (approx. 3 vol.%), with sizes of 0.3–1.5 mm (Fig. 1.3E). The accessory minerals are zircon, fluorite and apatite.

The HD pluton, in which biotite granite is well exposed, crops out near Xiaohada

Village. It also intruded into the Permian Linxi Formation, and the northern part of its boundary is covered by Quaternary sediments. Petrographically, the biotite granite is light grey, medium-grained in texture (2–5 mm in size) and massive in structure (Fig.

1.3F). Rock-forming minerals include quartz (45–50 vol.%), K-feldspar (30 vol.%), plagioclase (approx. 15 vol.%) and minor biotite (5–10 vol.%), accompanied by accessory fluorite, zircon, apatite and magnetite.

4 Analytical methods

4.1 Zircon U–Pb analyses

Zircon crystals were extracted from whole-rock samples by conventional electromagnetic and heavy-liquid separation methods, followed by handpicking under a binocular microscope at the Langfang Honesty Geological Services Co., Ltd. (China).

The selected zircon grains were mounted on epoxy resin, polished to expose the grains and photographed under transmitted and reflected light. Cathodoluminescence (CL) images were obtained for zircons prior to analysis using a JEOL scanning electron microscope (JSM6510) at Beijing GeoAnalysis Co., Ltd. (China) to examine the internal structures and identify and select distinct domains within zircons for laser ablation (LA). Representative CL images of the zircon grains are shown in Fig. 1.4.

U–Pb analyses of three samples (BSFZ-G01, BSFZ-G02 and HD-G01) were conducted using an LA-multiple collector-inductively coupled plasma-mass spectrometer (LA-MC-ICP-MS) at the National Research Center for Geoanalysis,

Chinese Academy of Geological Sciences. Each analysis incorporated a background

acquisition lasting approximately 20 s (gas blank), followed by data acquisition from the sample for 40 s. Helium was used as the carrier gas to enhance the transport efficiency of the ablated material. The analytical laser frequency was 10 Hz, and the spot diameter was 25 µm. The analytical approach was to conduct 10 measurements of unknown zircons between 3 measurements of standard zircons GJ-1 (n = 2) and

Plesovice (n = 1). The detailed analytical method broadly followed that presented in

Jackson et al. (2004). Zircon U-Pb dating and trace element contents were processed using the Glitter program (Version 4.0) of Macquarie University.

Fig. 1.4 CL images of representative zircons from the Linxi granitoids.

Zircon U–Pb isotopic dating of the other two samples (BS-G01 and XNG-G01) was performed at the State Key Laboratory of Geo-Processes and Mineral Resources,

China University of Geosciences (Beijing) (CUGB), using a Geolas 193 excimer solid sampling system as the LA system, coupled to a Thermo Fisher X Series II quadrupole

ICP–MS. The laser beam size was 32 µm, the frequency was 8 Hz, and helium was used as the carrier gas. A National Institute of Standards and Technology (NIST)

SRM610 standard was used for external trace element concentration calibration, and zircon 29Si concentrations were used for internal standardization. The zircon 91500 international standard was used for external age calibration and was analysed twice every five analyses (i.e., 2 zircon 91500 + 5 samples + 2 zircon 91500). The preferred

U-Th-Pb isotopic ratios used for 91500 were obtained from Wiedenbeck et al. (1995).

The detailed analytical procedures were described by Cao et al. (2017a). The ages were calculated by ICPMSDataCal software (Liu et al. 2008).

All the concordia diagrams and weighted mean calculations were generated using

Isoplot 3.0 software (Ludwig 2003). Individual analyses are presented with 1σ errors in data tables and concordia diagrams, whereas uncertainties in age results are quoted at the 95% level (2σ).

4.2 Whole-rock geochemical analyses

Whole-rock samples were crushed in an agate mill to ~200 mesh after removing the weathered surfaces. Whole-rock geochemical analyses were performed at the

Analytical Laboratory Beijing Research Institute of Uranium Geology (ALBRIUG).

Major element analysis was conducted using a Philips PW2404 X-ray fluorescence

spectrometry (XRF). The uncertainties for most major oxides were < 2%, whereas those for MnO and P2O5 were < 5%; the totals were within 100 ± 1%. Loss on ignition (LOI) was measured after heating the samples to 1000 °C. Meanwhile, trace element analysis was performed using ICP-MS (Finnigan MAT Element I ICP-MS). The precision for most elements was typically better than 5% (relative standard deviation), and the measured values for Zr, Hf, Nb and Ta were within 10% of the certified values (Ge et al. 2015). The detailed testing methods were described by Gao et al. (2002) and Wang et al. (2015b).

4.3 In situ zircon Hf isotopic analyses

In situ Hf isotopic analyses of the zircons were performed using a New Wave

UP213 laser-ablation microprobe attached to a Neptune multi-collector ICP-MS at the

Institute of Geology, Chinese Academy of Geological Science (Beijing, China).

According to zircon size, the ablating diameter was set at 44 μm on top of the U-Pb laser spot positions. Helium was used as a carrier gas to transport the ablated sample from the LA cell to the ICP-MS torch via a mixing chamber where it was mixed with argon. The detailed operating conditions for the LA system and the MC-ICP-MS instrument and the analytical methods were the same as those described by Hou et al.

(2007) and Wu et al. (2006). To correct the isobaric interferences of 176Lu and 176Yb on

176Hf, the 176Lu/175Lu and 176Yb/173Yb ratios (0.02658 and 0.796218, respectively) were determined (Chu et al. 2002). For instrumental mass bias correction, Yb isotope ratios were normalized to a 172Yb/173Yb ratio of 1.35274 (Chu et al. 2002), and Hf isotope ratios were normalized to a 179Hf/177Hf ratio of 0.7325 using an exponential law. Zircon

GJ1 was used as the reference standard. The weighted average 176Hf/177Hf of the GJ1 zircon samples was 0.282007 ± 0.000007 (2σ, n = 36), which is in agreement with the recommended weighted mean 176Hf/177Hf ratio (0.282015 ± 19) (2σ) reported by Elhlou et al. (2006).

5 Analytical results

5.1 Zircon U–Pb ages

Here, I present five zircon LA–ICP–MS U–Pb ages for the four plutons described in section 3. The representative locations of the LA–ICP–MS U–Pb isotope analytical points are marked by green circles (Fig. 1.4). The zircons selected for analysis are mainly euhedral to subhedral prismatic grains with a long axis diameter of 40–150 μm and length/width ratios between 1 and 3. The results of the zircon U–Pb isotopic analysis are listed in Table 1.2.

5.1.1 BSFZ pluton

Sample BSFZ-G01, a fine-grained granodiorite, was collected from the BSFZ pluton. The 206Pb/238U ages from 21 points range from 242 to 269 Ma, yielding a weighted mean age of 252 ± 3 Ma (mean square weighted deviation [MSWD] = 0.54)

(Fig. 1.5a). This Late Permian age is regarded as representing the crystallization age of the granodiorite.

Sample BSFZ-G02 is a granodiorite porphyry collected from the south part of the

BSFZ pluton. Fig. 1.5b shows that the analytical data points of the zircons are tightly clustered and define a weighted 206Pb/238U age of 246.3 ± 3.3 Ma with an MSWD =

0.26. The concordant age corresponds to the crystallization age of the granodiorite

porphyry.

5.1.2 XNG pluton

Seventeen points on a monzogranite (Sample XNG-G01) of the XNG pluton were analysed, and they constitute a coherent group clustering tightly on or around the concordia (Fig. 1.5c). I obtain a weighted mean 206Pb/238U age of 251.1 ± 2.8 Ma

(MSWD = 1.6, n = 17) within the error, which represents the emplacement time of the monzogranite.

5.1.3 BS pluton

Sample BS-G01 is a granite that was collected from the BS pluton. All 13 analyses fall on or adjacent to the concordia in the 206Pb/238U–207Pb/235U concordia diagram (Fig.

1.5d) and yield a weighted mean age of 220.8 ± 2.7 Ma (MSWD = 0.05, n = 13). This weighted mean age is interpreted as the formation age of the granite.

5.1.4 HD pluton

A medium-grained biotite granite sample (HD-G01) taken from the HD pluton contained abundant zircons. In total, 21 analyses were performed on representative zircon grains, showing concordance within analytical errors on the U-Pb concordia diagram (Fig. 1.5e). A weighted mean 206Pb/238U age of 211.4 ± 2.6 Ma (MSWD = 0.94, n = 21) was obtained, which is regarded as the intrusive age of this granite.

Fig. 1.5 Zircon U–Pb concordia diagrams and weighted mean 206Pb/238U ages for the (a and b) BSFZ pluton, (c) XNG pluton, (d) BS pluton, and (e) HD pluton. (f) Relative probability plot of zircon data from granitoids in the Linxi area and adjacent regions. The zircon U–Pb ages are from this study and the literature (Table 1.5).

5.2 Whole-rock major and trace elements

All analytical data and calculated parameters of the representative samples of the

four plutons are provided in Table 1.3. The samples selected for analysis are classified as granite, monzogranite and granodiorite on the quartz-alkali feldspar-plagioclase

(QAP) diagram (Fig. 1.6a) and lie across the granodiorite to granite fields on the SiO2 versus ALK (ALK = Na2O + K2O) diagram (Fig. 1.6b). By combining their petrologic characteristics, ages and spatial distributions, the studied intrusive rock samples can be divided into three groups: (1) the BSFZ pluton, (2) the XNG pluton, and (3) the BS and

HD plutons.

5.2.1 Group 1: the BSFZ pluton

Samples from group 1 have similar major and trace element compositions. They have restricted ranges of SiO2 (63.88–67.34 wt.%) and Al2O3 (15.51–16.84 wt.%), variable contents of ALK (4.70–6.80 wt.%), and moderate contents of MgO (1.32–2.17 wt.%) and CaO (3.99–5.11 wt.%), with low TiO2 (0.44–0.82 wt.%), MnO (0.04–0.06 wt.%), and P2O5 (0.13–0.18 wt.%). They fall into the subalkaline field on the SiO2 versus ALK diagram (Fig. 1.6b). On the SiO2 versus K2O diagram (Fig. 1.6c), the granodiorites belong to the medium-K calc-alkaline series, while the granodiorite porphyries from the southern part of the BSFZ pluton belong to the high-K calc-alkaline series. As shown in the [Al2O3/(Na2O + K2O + CaO)] (A/CNK) versus [Al2O3/(Na2O +

K2O)] (A/NK) classification diagram (Fig. 1.6d), the samples from group 1 are metaluminous to weakly peraluminous with low A/CNK values of 0.95–1.05.

Fig. 1.6 Classification and series geochemical discrimination diagrams of the Linxi granitoids. (a)

QAP modal classification (after Le Maitre 2002), (b) SiO2 versus ALK diagram (Middlemost 1994),

(c) SiO2 versus K2O diagram (after Peccerillo and Taylor 1976), and (d) A/CNK versus A/NK diagram (after Maniar and Piccoli 1989). Published geochemical data can be found in literature listed in Table 1.5.

The granodiorites and granodiorite porphyries show different total rare earth element (REE) concentrations of 68.5–79.4 and 145.1–148.3 ppm, respectively, but they display similar chondrite-normalized REE patterns (Fig. 1.7a), which are characterized by relatively light REE (LREE) enrichment (LaN/YbN = 4.62–10.36), flat heavy REE (HREE) patterns, clear negative Eu anomalies (Eu/Eu* = 0.57–0.70) and weakly negative Ce anomalies (Ce/Ce* = 0.81–0.95). In the N-MORB normalized

diagram (Fig. 1.7b), they show depletion in Ba, Nb, Ta, P and Ti and enrichment in Rb,

Th, U, K, Pb, Nd, Zr and Hf.

1000 Published data (a) 1000 (b) in the region 100 Published data 100 in the region

MORB 10 10 -

1 BSFZ pluton 1 Rock/N

Rock/Chondrite XNG pluton granodiorites 0.1 BS pluton granodiorite porphyries HD pluton 0.1 0.01 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Rb Th Nb K Ce Pr Nd Sm Hf Ti Dy Er Lu Ba U Ta La Pb Sr P Zr Eu Tb Y Yb Fig. 1.7 (a) Chondrite-normalized REE and (b) N-MORB normalized trace element spider diagrams of the Linxi granitoids. Normalization values are from Sun and McDonough (1989). Published geochemical data can be found in literature listed in Table 1.5.

5.2.2 Group 2: the XNG pluton

Late Permian monzogranites collected from the XNG pluton exhibit high contents of SiO2 (69.31–72.91 wt.%), K2O (4.35–6.31 wt.%) and Na2O (3.45–4.93 wt.%) and low Al2O3 (13.21–15.17 wt.%), MgO (0.35–0.46 wt.%), CaO (0.86–1.98 wt.%), MnO

(0.02–0.03 wt.%) and P2O5 (0.04–0.06 wt.%). All the samples belong to the high-K calc-alkaline series (Fig. 1.6c) and show metaluminous characteristics (Fig. 1.6d), with

A/CNK values of 0.92–0.97 and A/NK values of 1.07–1.18.

The monzogranites contain relatively low total REE contents, which vary from

71.8 to 105.3 ppm with a mean value of 79.4 ppm. LREEs are strongly enriched relative to HREEs, with high LREE/HREE ratios (LaN/YbN = 14.67–20.35) and weakly negative or small positive Eu anomalies (Eu/Eu* = 0.85–1.37). Chondrite-normalized

REE patterns of the samples from group 2 decrease to the right, similar to the patterns

of group 1 (Fig. 1.7a). The large-ion lithophile elements (LILEs; e.g., Rb, Ba, K and

Pb) are strongly enriched, and high-field strength elements (HFSEs; e.g., Nb, Ta, P and

Ti) are relatively depleted in the monzogranites (Fig. 1.7b).

5.2.2 Group 3: the BS and HD plutons

Late Triassic granites collected from the BS and HD plutons are highly siliceous, with limited variation of their SiO2 contents (74.24‒77.34 wt.%). They have similarly high K2O contents (4.43‒6.67 wt.%) and low Na2O contents (0.19‒0.7 wt.%), with

K2O/Na2O values ranging from 7.09 to 30.16. They display low contents of Al2O3

(11.78–13.5 wt.%), MgO (0.07–0.18 wt.%), MnO (0.01–0.04 wt.%) and P2O5 (0.02–

0.03 wt.%). The granites define a subalkaline suite on the SiO2 versus ALK diagram

(Fig. 1.6b) and plot in the high-K calc-alkaline series field on the SiO2 versus K2O diagram (Fig. 1.6c). The samples plot in or near the field of weakly peraluminous rocks with restricted ranges of A/CNK ratios (0.98–1.08), and only two samples are metaluminous (Fig. 1.6d).

The granites from group 3 exhibit relatively high total REE contents (160.8–341.3 ppm) compared with the intrusive rocks from other groups. Samples from the HD pluton show right-sloping “seagull” patterns (Fig. 1.7a), with LaN/YbN ratios of 6.89–

14.68. In contrast, samples from the BS pluton show relatively flat “seagull” patterns

(Fig. 1.7a), with LaN/YbN ratios ranging from 0.99 to 1.64. Members of group 3 exhibit weak to negligible Ce anomalies (Ce/Ce* = 0.97–1.05) and significant negative Eu anomalies (Eu/Eu* = 0.03–0.13). As shown in the N-MORB normalized trace element diagram (Fig. 1.7b), the granites are enriched in LILEs (e.g., Rb and K) and Pb, and

relatively depleted in HFSEs (e.g., Nb, Ta, P and Ti), in addition to Ba and Sr, which are considered to be plagioclase-compatible elements (Dong et al. 2014).

5.3 Zircon Hf Isotopes

Hf isotopic analyses were conducted on the zircon grains used for U-Pb dating.

The representative analytical locations are labelled with yellow dashed broken circles in Fig. 1.4. The Hf isotope analysis data and calculation results are listed in Table 1.4.

The measured magmatic zircons display very homogenous Hf isotopic compositions. All the samples fall within the field between the Chondritic Uniform

Reservoir (CHUR) and the depleted mantle line (Fig. 1.8a), in good agreement with zircons from Phanerozoic granitoids reported in the CAOB (Chen et al. 2009; Dong et al. 2016; Shu et al. 2014; Yang et al. 2006). The 176Lu/177Hf ratios range between

0.000466 and 0.005472 with an average of 0.001392, indicating slight radiogenic growth of 176Hf (Han et al. 2012). A total of 66 analyses define the variation in the

176Hf/177Hf ratios (0.282802–0.283032). All zircons show positive Hf(t) values (Fig.

1.8b) ranging between 6.6 and 14.1 with an average of 10.1. The single-stage Hf model ages (TDM) and two-stage model ages (TDM2, Fig. 1.8c) vary from 317 to 634 Ma and from 355 to 857 Ma, respectively. The fLu/Hf values vary between -0.99 and -0.84 and are lower than the fLu/Hf values of mafic crust (-0.34; Amelin et al. 1999) and sialic crust

(-0.72; Vervoort and Jonathan Patchett 1996). In this case, the TDM2 can better represent the extraction time of the source material from the depleted-mantle reservoir or the mean crustal residence time of the source material (Blichert-Toft and Albarède 1997).

Fig. 1.8 (a) Ages of zircons versus εHf (t) values diagram for the Linxi granitoids, (b) histogram of zircon Hf (t) values of zircons, and (c) histogram of the two-stage Hf model ages (TDM2). CAOB

= the Central Asian Orogenic Belt; YFTB = the Yanshan Fold and Thrust Belt (Yang et al. 2006). 6 Discussion

6.1 Timing of magmatism in the Linxi area

There is a broad consensus that the XMOB was mainly formed from the closure of the PAO and special “soft collisions” among multiple (micro-)blocks (Jahn et al.

2004a; Li, 2006; Xiao et al. 2003; Zou et al. 2014). Thus, intensive magmatism occurred in the XMOB via long-lived subduction-accretionary processes (Li et al.

2016a; Xiao et al. 2015b). As shown in Fig. 1.2, granitoids are widely distributed in the

Linxi area. The timing and stages of the emplacement of these intrusive rocks can provide fundamental constraints on the nature and evolution of the magmatic processes.

In this study, zircon crystals are euhedral–subhedral and exhibit obvious oscillatory growth zoning in CL images (Fig. 1.4). Their specific CL properties, together with their

Th/U values of 0.21–1.36, indicate a magmatic origin (Koschek, 1993; Rubatto and

Gebauer, 2000). Therefore, I conclude that the U–Pb zircon ages obtained for these granitoids most likely represent their emplacement ages. The LA-ICP-MS dating results suggest that the four plutons studied here were emplaced in two stages: (1) Late

Permian–Early Triassic (ca. 252–246.3 Ma; BSFZ and XNG plutons) and (2) Late

Triassic (ca. 220.8–211.4 Ma; BS and HD plutons). Thus, punctuated and multiple episodes of granitic magmatism occurred in the study area from the Late Permian to the

Late Triassic.

To obtain a more comprehensive understanding of magmatism, here, I integrate 95 recently published single-zircon U–Pb ages of granitoids in adjacent areas (Bao et al.

2007; Gao et al. 2016; Ge et al. 2005; Li et al. 2007a; Li et al. 2016a; Li et al. 2016b;

Liu et al. 2009; Liu et al. 2005; Liu et al. 2012b; Miao, 2003; Pei et al. 2017; Shi et al.

2003; Shi et al. 2004; Wu et al. 2011a; Zeng et al. 2015; Zhai et al. 2014a; Zhai et al.

2014b). According to these precise geochronological data (Table 1.5), four main periods of granitic magmatic activity can be distinguished in this area (Fig. 1.5f): Late

Carboniferous (330–300 Ma), Early Permian (290–270 Ma), Late Permian–Late

Triassic (260–220 Ma), and Late Jurassic–Early Cretaceous (150–110 Ma). The occurrence of the youngest age group may be related to the westward subduction of the

Pacific Plate (Ouyang et al. 2013; Wilde, 2015; Wu et al. 2011a; Zhou and Wilde, 2013) and the southward subduction of the Mongol-Okhotsk oceanic plate (Li et al. 2018, Liu et al. 2018; Tang et al. 2016). Other age groups are most likely controlled by the subduction–collision processes driven by the closure of the PAO between the Siberia

Craton (SC) and the North China Craton (NCC) (Li et al. 2016a; Liu et al. 2015). In

addition to the relatively continuous magmatism discussed above, several episodes of magmatic quiescence or hiatus can be recognized at 300–290 Ma, 270–260 Ma and

220–150 Ma, some of which may act as predictors of the response to certain amalgamation and collision events.

6.2 Genetic types

6.2.1 BSFZ and XNG granitoids

The genetic types of granitoids in Northeast China are predominantly A-type or I- type (Wu et al. 2011a), while S-type granitoids have been identified only in limited areas (Cheng et al. 2006). The petrogeochemical signatures of A-, I-, and S-type granitoids are well documented by numerous studies (Chappell, 1999; Chappell et al.

2012; Chappell and White, 1992; Clemens, 2003; Eby, 1990; Ghani et al. 2013; Li et al. 2007b; Whalen et al. 1987). The investigated samples from the BSFZ and XNG plutons belong to the calc-alkaline to high-K calc-alkaline series and share similar geochemical features of high SiO2 (63.88–72.91 wt.%) and Na2O (2.08–4.93 wt.%) and low P2O5 (< 0.18 ppm) concentrations. The relatively low A/CNK ratios (0.92–1.05), together with the absence of typical peraluminous minerals (e.g., cordierite, muscovite, and garnet), distinguish them from S-type granitoids (Barbarin 1999; Cao et al. 2017b;

Chappell 1999; Wang et al. 2015a; Zhang et al. 2016a). These geochemical features are consistent with the coeval I-type granitoids (255–251 Ma) in the Xilinhot area of Inner

Mongolia (Li et al. 2016a). In the 10000*Ga/Al versus (Zr + Nb + Ce + Y) and

10000*Ga/Al versus (TFeO/MgO) diagrams (Fig. 1.9a and Fig. 1.9b), the rock samples from these two plutons mostly plot within the I-, S- & M-type fields, and a minor group

of the BSFZ granodiorites plots in the transitional field of A-type to I-, S- and M-type fields. Additionally, a negative relationship exists between P2O5 and SiO2 (Fig. 1.10a), while the Pb contents show a good, positive correlation with SiO2 (Fig. 1.10b).

Moreover, both Y and Th concentrations are positively correlated with Rb (Fig. 1.10c and Fig. 1.10d). The above geochemical features reflect typical I-type characteristics

(Chappell 1999; Li et al. 2007b). Therefore, I suggest that the granitoids from the XNG and BSFZ plutons can be considered as I-type granitoids.

600 100 (a) (b) 500 A-type A-type 400

300 10 FG

I-, S- & TFeO/MgO 200 M- type BSFZ pluton BSFZ pluton XNG pluton XNG pluton

Zr+Nb+Ce+Y(ppm) 100 BS pluton BS pluton OGT HD pluton HD pluton 0 1 1 10 1 10 10000*Ga/Al 10000*Ga/Al

Nb (c) Nb (d) BS pluton HD pluton

A1 A1

A2 A2

Y Ce Y 3Ga

Fig 1.9 (a and b) Geochemical classification (after Whalen et al. 1987) and (c and d) discrimination diagrams of the tectonic setting (after Eby 1992) of the Linxi granitoids. A1, anorogenic granite; A2, post-orogenic granite.

0.2 50 (a) (b) BSFZ pluton BSFZ pluton XNG pluton 40 XNG pluton

30 I-type trend

0.1 /wt /wt % 5 I-type trend

O 20

Pb(ppm)

2 P

0 0 60 65 70 75 60 65 70 75 SiO2/wt % SiO2/wt % 40 40 (c) BSFZ pluton (d) BSFZ pluton XNG pluton I-type trend XNG pluton 30 30 I-type trend

20 20

Y(ppm) Th(ppm) 10 S-type trend 10 S-type trend

0 0 80 120 160 200 80 120 160 200 Rb(ppm) Rb(ppm)

Fig. 1.10 Plots of (a) P2O5 versus SiO2, (b) Pb versus SiO2, (c) Y versus Rb and (d) Th versus Rb for samples from the BSFZ and XNG plutons (after Chappell and White 1992; Li et al. 2007b).

6.2.2 BS and HD granites

The Late Triassic BS and HD granites are characterized by high SiO2 (74.24–

77.34 wt.%), ALK (5.06–7.17 wt.%), TFeO/MgO and Ga/Al and low Al2O3 (11.78–

13.5 wt.%), MgO (0.07–0.18 wt.%) and CaO (2.63–3.76 wt.%). The REE distributions

(Fig. 1.7a) show slight enrichment in LREEs with respect to HREEs and clear negative

Eu anomalies (Eu/Eu* = 0.03–0.13). As shown in the trace element spider diagrams

(Fig. 1.7b), they are enriched in Rb, Th, U, Pb, Zr and Hf and depleted in Ba, Sr, P, Eu and Ti. The above distinctive geochemical characteristics are consistent with typical A- type geochemical affinity (Bonin 2007; Grebennikov 2014; King et al. 1997; Whalen

et al. 1987). Furthermore, the 10000*Ga/Al ratios vary from 2.9 to 4.4 with an average of 3.5, which is close to the value (3.75) of typical A-type granites reported by Whalen et al. (1987). Additionally, all the samples fall in the field of A-type granite on the geochemical classification diagram (Fig. 1.9). Coupled with the coeval acidic intrusions in the XMOB, I conclude that the BS and HD granites can be classified as typical A- type granites.

6.3 Nature of the magma sources

As noted above, the investigated granitoids were emplaced in different stages varying from the Late Permian to Late Triassic. The granitoids with different ages show positive and homogeneous εHf(t) values with a relatively narrow range from 6.6 to 14.1.

In addition, these rocks have very young Hf two-stage model ages (355–857 Ma, average: 619 Ma). Zircon can effectively preserve the initial 176Hf/177Hf ratio from the source area, and their Hf isotope isotopic compositions facilitate determining the source of the granitoids (Pei et al. 2018; Wang et al. 2016a). All of the samples fall into the field of igneous rocks in the East CAOB. Zircon Hf isotopic data indicate that the source for their magma was derived from the mantle-derived material or juvenile crust.

Whereas the I-type and A-type granitoids exhibit distinct geochemical features. Thus, I discuss them separately.

6.3.1 I-type BSFZ and XNG granitoids

The samples from BSFZ pluton show intermediate–high SiO2 (63.88–66.78 wt.%), high Al2O3 (15.51–16.84 wt.%), high Na2O and low HREE, which are similar to typical subduction related arc granitoids (Pearce 1996). The BSFZ granitoids contain

high Cr, Ni and Sc, in conjunction with relatively high MgO (1.31–2.17 wt.%) and Mg#

(30.16–38.17), implying a significant input of mantle source magmas (Smithies et al.

2000). The XNG granitoids show higher SiO2 (69.31–72.91 wt.%), lower Al2O3 (13.21–

15.71 wt.%), MgO (0.35–0.46) and Mg# (23.26–26.09), indicating minor involvement of mantle source magmas. The Nb/Ta (5.88–12.74, average: 9.20) and Zr/Hf (23.82–

36.84, average: 31.31) ratios of the I-type BSFZ and XNG granitoids are more similar to those of the crust (11.4 and 33, respectively) than those of primitive mantle (17.8 and

37, respectively), indicating derivation is close to a crustal source (Dostal and

Chatterjee 2000; Green 1995; Wang et al. 2016b). Combined with Hf isotopic data, the the magma source of I-type BSFZ and XNG granitoids were most likely to be dominated by juvenile crustal materials with input of mantle-derived magma at different degree.

6.3.2 A-type BS and HD granites

The A-type BS and HD granites have a relatively concentrated geochemical and are characterized by significant high SiO2, high ALK and high K2O, and low Al2O3, Cr and Ni concentrations. All of the samples exhibit low MgO contents (0.07–0.18) and

Mg# values (6.93–11.89). These geochemical characteristics suggests that the involvement of mantle-derived magmas was negligible (Rapp and Watson 1995; Yang et al. 2016a) and they were likely derived from partial melting of lower crust material

(Hofmann 1988). Furthermore, the majority of Mesozoic granitoids (250–105 Ma) in the Linxi area are characterized by positive εNd(t) and young TDM values (Yang et al.

2017 and references therein), implying that they were mainly melted from a juvenile

crust (Liu et al. 2012a; Yang et al. 2017).Compared with the BSFZ and XNG granitoids, the samples from the BS and HD plutons show significant depletions of Nb, Ta, Ti, Ba,

Sr, P and Eu, which suggest that rutile, Fe–Ti oxides, and apatite were rare or absent in the magma sources (Guo et al. 2016). It is here noted that the pronounced depletions in the above elements also imply the existence of fractional crystallization of plagioclase,

K-feldspar and apatite during the evolutionary processes of rising magma (Shu et al.

2014; Wang et al. 2015b; Zhou et al. 2015b).

6.4 Tectonic interpretation and evolution

6.4.1 During the Late Palaeozoic–Early Mesozoic

There is a broad consensus that the final closure of the PAO occurred along the

Solonker–Xar Moron suture zone, which is marked by melanges, blueschists and the

Solonker–Sonidyouqi–Kedanshan–Xingshuwa ophiolite belts (Chen et al. 2009;

Eizenhöfer et al. 2014; Jian et al. 2010; Li et al. 2014a; Şengör et al. 1993; Wu et al.

2007). The final disappearance of the PAO resulted in a collision between the NCC and the SC (Li et al. 2016b; Windley et al. 2007). Several subdivision schemes in terms of the tectonic evolutionary history have been proposed (e.g., Chen et al. 2009; Eizenhöfer et al. 2014; Song et al. 2015). Crustal growth and tectonic evolution of orogenic belts can be deciphered by the accompanying magmatism (Wu et al. 2011a). As noted in section 6.1, multiple episodes of magmatism can be identified in this area, which are closely linked to the orogenesis of the XMOB in response to subduction–accretion– collision processes along convergent margins (Li et al. 2016a). Here, based on these new data and previous studies, I propose three stages of tectonic evolution during the

Late Palaeozoic–Early Mesozoic in the XMOB (Fig. 1.11).

Fig. 1.11 Schematic diagrams showing the tectonic evolution of the XMOB (modified from Gao et al. 2016; Li et al. 2016a).

a. Late Carboniferous–Early Permian subduction (330–270 Ma)

The subduction of the PAO lithosphere beneath the NCC during the Late

Ordovician to the Devonian resulted in the formation of the Southern Accretionary

Orogen, an Andean-type continental margin (Jian et al. 2010). In the Carboniferous, the

Northern Accretionary Orogen formed due to the north-dipping intraoceanic subduction of the PAO, which is marked by the Baolidao–Xinlinhot–Xiwuqi arc–accretion complex and the Erdaojing Subduction–Accretion Complex (Chen et al. 2009; Xiao et al. 2003). The Late Carboniferous granitoids (330–300 Ma) are subduction-related intrusions and tend to become younger southeastward and to migrate towards the southeastern part of the arc–accretion complex (Li et al. 2016b). As shown in Fig. 1.5f, magmatism in the Linxi area ceased from 300 to 290 Ma, as confirmed by the fact that few zircons with such ages are observed in the Permian arc basins (Eizenhöfer et al.

2014). However, in other regions of the XMOB, a gabbro (296.6 ± 1.7 Ma) and tonalite

(294.9 ± 2.4 Ma) along the Solonker suture were reported by Jian et al. (2010), together with bimodal volcanic rocks (Zhang et al. 2008b) and A-type granites (Zhang et al.

2015c) from central Inner Mongolia, suggesting an extensional event during the Early

Permian. Early Permian granites (290–270 Ma), which are widespread in the Linxi area, resulted from ongoing bivergent subduction. The sedimentary environment of the protolith of the Shuangjing Complex is believed to be an arc/forearc basin during the

Late Carboniferous–Middle Permian (Li et al. 2011). In addition, this scenario of continuous subduction from 290 to 270 Ma is supported by the existence of an Early

Permian ophiolitic mélange (Jian et al. 2010; Song et al. 2015).

b. Middle Permian–Middle Triassic collisional orogeny (270–237 Ma)

The PAO started to close because of bidirectional subduction that continued from the Early to Middle Permian (Xiao et al. 2003). This double-sided subduction model is supported by the overall geometry of the mantle reflectors across the Solonker suture zone (Zhang et al. 2014a). More recently, Chen et al. (2016) documented a carbonatite intrusion with geochemical features of recycled limestone, providing convincing evidence of the presence of the PAO slab beneath the NCC. A weak magmatic hiatus during the Middle Permian (Fig. 1.5f, 270–260 Ma) may have been caused by a decrease in the slab pull force (Li et al. 2016b), which implies that the initial collision along the Solonker–Xar Moron suture zone occurred during this period, as confirmed by the intrusion of the syncollisional Fangkuangzi granite (272 ± 2–265 ± 2 Ma) in the

XMOB (Li et al. 2014b). This implication is in accordance with the disappearance of the biological migration barrier in the PAO during the Early Permian marked by the mixture of the warm- and cold-water species in the Lower Permian Sanmianjing

Formation of the XMOB (IGSCUGB 2008). Subsequent collision-accretion processes led to crustal uplift, thickening and regional metamorphism along the Solonker suture zone (Li 2006; Wu et al. 2007), accompanied by widespread magmatism during the

Late Permian to Late Triassic. The formation of the I-type BSFZ and XNG granitoids

((272 ± 2)–(265 ± 2) Ma) in the study area, along with adakites, S-type granites, high- magnesian andesites and sanukitoids, was a response to possible fossil slab break-off, lithospheric delamination and asthenospheric upwelling soon after the initial collision

(Jian et al. 2010; Li et al. 2013a; Liu et al. 2012b). Li et al. (2007a) reported that the

Shuangjingzi syncollisional crust-derived granite intruded the Late Palaeozoic accretion-collisional complex to the north of the Xar Moron River at approximately

237.5 Ma, which implies that the collision process lasted to the Middle Triassic.

c. Late Triassic post-collisional extension (237–211 Ma)

Before the Late Triassic, a few intrusive rocks (e.g., sanukitoids) along the

Solonker suture zone formed in a post-orogenic or post-collisional setting as discussed by Jian et al. (2010) and Zhang et al. (2015c), but this zone may represent a limited extensional environment. The BS and HD granites ((220.8 ± 2.7)–(211.4 ± 2.6) Ma, this study) are typical A-type granites and fall into the A2-type field in the Y–Nb–Ce and

Y–Nb–Ga×3 diagrams (Fig. 1.9c and Fig. 1.9d), which implies they were derived by the partial melting of continental crust that had been through a cycle of continent- continent collision (Eby 1992). In the large-scale tectonic framework, extensive highly fractionated I-type and A-type granitoids were manifest in the XMOB and the northern margin of the NCC in the Late Triassic (Chen et al. 2009; Li et al. 2016a; Liu et al.

2015; Wu et al. 2011a; Yang et al. 2014a; Zhang et al. 2009a). In conjunction with the coeval eruption of shoshonitic basalts at approximately 224 Ma (Jian et al. 2008) and the record of representative Triassic detrital zircon age groups (227–219 Ma) from the

Xingfuzhilu Formation in southern Inner Mongolia (Li et al. 2014a), I argue that the

XMOB was in the stage of post-orogenic extension between 237 and 211 Ma. The post- orogenic extension also led to the development of extensional basins (Xiao et al. 2003), strike-slip faults (Ma 2009; Zhao et al. 2015) and metamorphic core complexes (Davis et al. 2004).

6.4.2 During the Late Jurassic–Early Cretaceous

There exsited a magmatic hiatus in Linxi area during the Early-Middle Jurassic

(Fig. 1.5). Magmatic rocks formed during this period were only reported in the Lesser

Xing’an–Zhangguangcai Ranges, Erguna region and eastern Heilongjiang-Jilin provinces (Li et al. 2018; Xu et al. 2013b). Subsequently, an intense magmatic activity took place during the Late Mesozoic (ca. 150–110 Ma), forming abundant granitoids, near-synchronous volcanic rocks, and related mineral deposits (Zeng et al. 2011; Ying et al. 2010; Zhang et al. 2010a). Those igneous rocks share similar isotopic features such as low initial 87Sr/86Sr ratios, positive εNd(t) and εHf(t) values, and young model ages (Hong et al. 2004; Yang et al. 2017). Meanwhile, the coeval volcanic rocks are dominated by A-type rhyolites, implying that they formed in an extensional tectonic setting (Li et al. 2018; Xu et al. 2013b). The extensive crustal extension during Late

Triassic–Early Cretaceous were recognized by multidisciplinary studies (e.g., Liu et al.

2017b; Mazukabzov 2012; Meng, 2003; Ren et al. 2002; Wang et al. 2012; Zhang et al.

2010a). However, the cause of the intense widespread magmatic and hydrothermal activity during this period remains controversial, with recent research suggesting several possible geodynamic regimes, including (1) mantle plume activity hypothesis

(e.g., Sobolev et al. 2011), (2) subduction of the Paleo-Pacific Ocean plate (e.g., Wu et al. 2011a; Zhang et al. 2010a); (3) influence of the Mongol–Okhotsk orogeny (e.g, Guo et al. 2017; Wang et al. 2015d). Furthermore, this intracontinental extensional event can also be attributed to the combined effects of the circum-Pacific and Mongol–Okhotsk tectonic regimes (Li et al. 2018). From the view of the entire Northeast Asia, extension

has occurred widely and performed as a regional tectonic event. During the early

Cretaceous (~137 Ma), tectonic transformation from NNE-trending contraction to

NNE-trending extension took place at Northeast Asia(Liu et al. 2017b). Subsequent regional extension and lithosphere thinning occurred, which triggered widespread magmatism and mineralization in this region.

7 Conclusions

(1) LA-ICP-MS U–Pb zircon dating results indicate that the emplacement of the

BSFZ, XNG, BS and HD plutons occurred in two stages: a. Late Permian to Early

Triassic (the BSFZ and XNG plutons, (252 ± 3)–(246.3 ± 3.3) Ma) and b. Late Triassic

(the BS and HD plutons, (220.8 ± 2.7)–(211.4 ± 2.6) Ma).

(2) Geochemical and Hf isotope data reveal that the magma source of I-type BSFZ and XNG granitoids were most likely to be dominated by juvenile crustal materials with input of mantle-derived magma at different degree. And the magma source of A-type

BS and HD granites were likely derived from partial melting of lower crust material.

(3) Based on these new data and previous studies, I propose three stages of tectonic evolution during the Late Palaeozoic–Early Mesozoic in the XMOB: a. Late

Carboniferous–Early Permian (330–270 Ma): double-sided subduction of the PAO; b.

Middle Permian–Middle Triassic (270–237 Ma): collisional orogeny; c. Late Triassic

(237–211 Ma): post-collisional extension; and d. intracontinental extension (~150 Ma–

~110 Ma).

Chapter 2: Geochronology, geochemistry, fluid inclusion and C,

O and Hf isotope compositions of the Shuitou fluorite deposit,

Inner Mongolia, China

1 Introduction

The Southern Great Xing'an Range is located in the eastern segment of the Central

Asian Orogenic Belt and incorporates widespread Mesozoic granitoids (Wu et al.,

2011a) and related endogenic mineral deposits (Ouyang et al., 2013). The major deposit types include porphyry, skarn, hydrothermal vein and epithermal types (Mao et al.,

2011). Several previous studies have addressed the Mesozoic metallogenic ‘explosion’ in the Southern Great Xing'an Range and its periphery, mainly focusing on the metallic deposits (e.g., Liu et al., 2016; Shu et al., 2013; Wang et al., 2001; Wang et al., 2006;

Pirajno et al., 2009; Zhou et al., 2015b). The occurrence of economically significant fluorite ore clusters was discovered recently in the area, such as the Sumochagan Obo fluorite cluster in Siziwang Banner (Xu, 2009), Linxi and Aohan fluorite clusters in

Chifeng area, Inner Mongolia (Chen, 2011; Pei et al., 2016; Zhang, 2014), and Yixian fluorite cluster in western Liaoning Province (Sun, 2007), thus making this region as one of the newly-developing fluorite resources of northern China. Compared with metallic deposits in the SGXR, the non-metallic mineral deposits, such as the fluorite deposits, are poorly studied.

Shuitou is one of the largest fluorite deposits in Inner Mongolia. Although this deposit has a long history of exploitation, there has been no detailed research on its

origin. Previous studies have mainly focused on the geology, geochemistry and ore- forming fluids of the deposit (Cao et al., 2014; Zhang et al., 2014b). However, several critical aspects, such as the geochronology of the fluorite mineralization and that of the related granites, the properties of the ore-formation fluids, among other factors, have not yet been investigated. The precise dating of fluorite deposits has long been as difficult problem. In earlier studies, several workers adopted K–Ar and Rb–Sr isotopic methods (e.g., Dos Santos and Bonhomme, 1991; Ruiz et al., 1984) using valencianite,

K feldspar and mica, which are rare in fluorite ores and rather sensitive to secondary alteration (Smolyanskii and Bogomolov, 2011). The Sm–Nd isotopic system is relatively robust and resistant to weathering and alteration (Chesley et al., 1991). Thus, fluorite Sm–Nd dating has been effectively applied to understand the ore-forming age of hydrothermal deposits (e.g., Barker et al., 2009; Galindo et al., 1994; Munoz et al.,

2005; Smolyanskii and Bogomolov, 2011; Xu et al., 2015c; Zhang et al., 2015a).

The present study aims to provide new constraints on the mechanism of formation of the Shuitou fluorite deposit. The new data that I present in this paper include: 1) Sm–

Nd geochronology of the deposit, 2) zircon U–Pb chronology, Hf isotope and whole- rock geochemistry of the associated intrusion, the Herimu Tai granite, 3) trace elements and fluid inclusions in the fluorite deposit, and 4) C–O isotopes of the associated major mineral (calcite). In combination with previous studies, I attempt to gain insights on the nature and genesis of the deposit and propose a model that would be useful in better understanding the ore-forming processes.

2 Geologic Setting

2.1 Regional Geology

Fig. 2.1 (a) Simplified tectonic map of northeastern China, showing the location of southern Great

Xing'an Range (modified after Wu et al., 2011) and the area of fluorite deposits prospecting

(modified after Wang et al., 2015c). (b) Sketch geological map of the SGXR, showing the distribution of mineral deposits in Late Mesozoic (after Ouyang et al., 2015) and regions rich in fluorite deposits (after Chen, 2011).

The SGXR is located to the west of the Nenjiang fault, north of the Xar Moron fault and south of the Erlian–Hegenshan fault (Fig. 2.1a). The region forms part of the eastern segment of CAOB between the Siberian Craton and the North China Craton, termed as the Xingmeng Orogenic Belt (XMOB). The CAOB represents of the largest

Phanerozoic orogen on the globe with extensive crustal accretion and recycling and

associated economic mineralization (Jahn et al., 2000b; Jahn et al., 2009; Şengör et al.,

1993; Xu et al., 2013a; Han et al., 2015; Huang et al., 2016; Xiao et al., 2015a; Wang et al., 2016c). The CAOB is composed of a series of Neoproterozoic to Mesozoic island arcs, forearc or back-arc basins, tectonic mélange belts and micro- continental blocks

(Windley et al., 2007). The XMOB, from north to south, has been divided into the northern accretionary belt, central Solonker composite suture and southern accretionary belt (Xiao et al., 2003). The SGXR is spread over the latter two domains. The CAOB records multiple tectonic events including the Paleo-Asian ocean closure (Xiao et al.,

2003; Zhang et al., 2009a), Mongol–Okhotsk ocean closure (Meng, 2003; Tang et al.,

2016; Wang et al., 2015d; Yang et al., 2015) and Paleo-Pacific plate subduction (Wu et al., 2011a), together with other tectonic events.

The major rock types exposed in the region are Permian and Jurassic. The Permian rocks are mainly composed of black slate, siltstone and sandstone whereas the Jurassic rocks are dominated by intermediate to felsic volcanoclastic rocks, tuff and rhyolite.

Several faults with different strike directions are developed within the area. Among these, the EW-striking structures evolved through complex processes and play a leading role in the structural framework of the area (Zhang et al., 2010b). The NE–NNE striking structures, like the Great Xing'an Range fault and the Nenjiang fault, are the most important regional fault structures within the area and their secondary faults serve as significant ore-controlling structures. The NE-striking faults represent tensional faults complimentary to the NW-striking transpressional faults. This structural framework controls the spatial distribution of the major mineral deposits (Fig. 2.1b). Multiple

magmatic events are recorded in the area, among which the Paleozoic–Mesozoic granites in the Central Asian Orogenic Belt have commonly positive Nd values and young Nd model ages (Hong et al., 2004). From SW to NE, the magmatism shows a transition from basic to intermediate-acid rocks (Shu et al., 2011), in which Triassic–

Cretaceous magmatic rocks are the most widespread and closely related to mineralization (Mao et al., 2011).

2.2 Geology of the Shuitou deposit

The Shuitou fluorite deposit occurs in the northwestern Linxi County in Inner

Mongolia, bordering the Hexigten Banner to the west, approximately 200 km from the

Chifeng City. The fluorite ore belt, from north to south, can be divided into three ore blocks (Fig. 2.2): 1) the northern block located in the Saiboluogoumen–Xiaoxigou area, where the ore-bearing belt discontinously extends for 2.5 km, 2) the central block in the

Husitaigoumen–Shuitou area, where ca. 1.5 km long ore-bearing belt is developed, and

3) the southern block in the Hanpaizi–Herimu Tai area, where the ore-bearing belt discontinously extends for about 4 km. The main ore-hosting rocks in the area comprise the Shoushangou Formation, Dashizhai Formation and Linxi Formation of Permian age, and the Manketouebo Formation of a Jurassic age. The major rock types include muddy-sandy slate, volcanic-sedimentary rock and carbonates. The Permian and Late

Jurassic granites are exposed in the western and eastern part of the study area respectively, and the Herimu Tai granite is mainly exposed in the southern part.

Fig. 2.2 Geological sketch map of the Shuitou fluorite deposit (modified after Zhang et al., 2014b) and morphological map within the north part of the study area based on WorldView-2 imagery.

Within the study area, the nearly SN-, NNE- and NNW- striking fluorite ore bodies occur in en echelon pattern and can be classified into three ore zones which strike nearly

N-S and extend discontinously for 10 km. These ore bodies display typical linear distribution (Fig. 2.2) and are hosted within ore-controlling faults mainly as veins and lenses (Fig. 2.3a), and extend along the faults (Fig. 2.3b). The ore bodies strike 350° to

20° and dip steeply at an angle of 70°–80°. Ore grade varies from 30% to 90%, with the fluorite ore in the central ore block showing an average ore grade of up to 78%. The deposit has a relatively simple mineralogy with mainly fluorite and quartz, which account for more than 95% of the total ore, followed by calcite, kaoline, chlorite and pyrite. The fluorite is green, purple, flesh pink, colorless and grayish whiteand the early stage mineralization shows fine- anhedral to subhedral granular texture (Fig. 2.3c, Fig.

2.3d), with the ore belonging to the quartz–fluorite type. Fluorite of the late stage is medium–coarse subhedral to idiomorphic granular (Fig. 2.3e, Fig. 2.3f), and the ore types include fluorite-quartz and fluorite. The breccias from surrounding rocks commonly occur both in early- and late-stage fluorite veins (Fig. 2.3d, Fig. 2.3f). The fluorite of early stage often brecciated cemented by late-stage fluorite veins (Fig. 2.3e,

Fig. 2.3f). Ore structures mainly include massive, banded, brecciated, lumpy and honeycomb structure. Large amounts of lattice-textured quartz (Fig. 2.3g) and bladed calcite (Fig. 2.3h) are developed within the area, suggesting that the ore-forming fluids experienced boiling (Dong et al., 1995; Etoh et al., 2002). As fluorite is easily decomposed, pores and cavities were formed through post-mineralization leaching at the surface (Fig. 2.3i).

Wallrock alteration is characterized by silification, followed by kaolinization, chloritization, sericitization, pyritic and carbonate alteration. Generally, silification is most intense near the ore bodies, and chloritization, sericitization and kaolinization become gradually strong towards the two margins. This zoning suggests discontinous interaction of fluids with wallrocks, and chemical potential gradients in the fluids during the water–rock reaction process that dicated the differentiation and evolution of hydrothermal fluids. The intensity of alteration becomes higher near the footwall of the ore bodies; the thicker the ore bodies are, the wider the alteration zoning is; and the width of alteration zoning generally varies from 0.5 m to 1.5 m.

Fig. 2.3 Field photographs of the Shuitou fluorite deposit. a: outcrops of ore bodies. b: typical section showing occurrence and morphology of the ore body. c and d: early stage fluorites. c: early stage fluorite and quartz vein intergrowthd. d: early stage fluorite vein with breccias. e and f: late stage fluorites crosscutting early stage fluorites. g: quartz with lattice texture. h: bladed calcite. i: cavities after the fluorites leached. Abbreviations: Fl-1, early stage fluorite; Fl-2, late stage fluorite;

Qtz, quartz; Cal, calcite.

3 Sampling and analytical methods

Six granite samples (ELMT–1~ELMT–6) used for this study were collected from

Herimu Tai area near the southern ore block. Samples of fluorite (ST–F08~ST–F12) and quartz (ST–Q01~ST–Q05) for analyses were mainly collected from adits and trenches in the central ore block. Samples ST–F08~ST–F10 represent the fluorite of early stage whereas ST–F11~ST–F12 represent the fluorite of late stage. Samples of

calcite (ST–C01~ST–C04) were mainly collected from trenches in Saiboluogoumen within the northern ore block. Samples for fluid inclusion studies were collected from the central and southern ore blocks. Those for fluorite Sm–Nd isotope analysis include six samples (ST–F01~ST–F06) from adits in the central ore block and one (ST–F07) from a trench in the southern ore block. All the samples used for analyses are fresh.

3.1 Major and trace elements

The major elements analyses of granite and trace and major element analyses of granite, fluorite, quartz and calcite were performed at the Analytical Laboratory of

Beijing Research Institute of Uranium Geology. Major elements of granite were assayed by X-ray fluorescence spectrometry (XRF) with analytical error less than 5%.

Single mineral separation of fluorite, quartz and calcite samples was done at Langfang

Honesty Geological Services Co., Ltd. China. The fluorite, quartz and calcite mineral separates were handpicked under a microscope, with a purity of above 99%, washed by distilled water and dried at a low temperature, and powered to 200 mesh in an agate mortar. The analyses of trace and major elements were performed at the Analytical

Laboratory Beijing Research Institute of Uranium Geology (ALBRIUG). Detailed on testing methods were described by (Gao et al., 2002; Wang et al., 2013). Uncertainties for most major oxides are < 2%, while the precision for most trace elements was typically better than 5% (relative standard deviation).

3.2 Fluid Inclusions

Fluid inclusion microthermometry was performed on the samples of fluorite at the

Fluid Inclusion Assay Room of State Key Laboratory of Geo-Processes and Mineral

Resources, China University of Geosciences (CUGB). The Linkam MDSG 600

Cooling-Heating Stage coupled to a polarizing microscope was used for inclusion observation and heating-cooling experiments in the temperature range from - 196℃ to

+ 600℃, with cooling and heating rate between 5℃/min to 20℃/min. The heating rate near the phase transformation point was controlled between 0.5℃/min and 1℃/min.

The precision is estimated as ±0.2 C when it comes to the temperature measurement during the observation of the phase changing.

In situ Raman spectroscopic analysis of fluorite inclusions was performed at the

Key Laboratory of Institute of Mineral Resources, Chinese Academy of Geological

Sciences, using a Renishaw System–2000 microscopic confocal laser Raman spectrometer. The laser excitation wavelength was 514.53nm, the laser power was

20mW, the minimum diameter of the laser beam was 1μm, the scanning range was

100cm-1 - 4500cm-1, the spectral resolution was 1 cm-1 - 2cm-1 and double polished wafers were used for the analyses.

3.3 Zircon U–Pb geochronology and Lu–Hf isotopes

Zircon grains were separated using conventional electromagnetic and heavy fluid separation methods at the Langfang Geosciences Exploration Technical Service

Limited Company, followed by handpicking under binocular microscope. The selected zircon grains were mounted on epoxy resin, polished to expose the grains and photographed under transmitted and reflected light, followed by cathode luminescence

(CL) imaging. The CL images, combined with the transmission and reflected photos,

were used to mark the spots without inclusions and fractures for laser ablation.

Zircon U–Pb isotopic dating was performed using LA–ICP–MS at the State Key

Laboratory of Geo-Processes and Mineral Resources, CUGB, using a Geolas 193 excimer solid sampling system as the laser ablation system, coupled to Thermo Fisher

X Series II quadrupole inductively coupled plasma mass spectrometry (ICP–MS). The laser beam size was 32μm, the frequency was 8Hz, and helium was used as carrier gas.

The American National Standard NIST610 was used for optimizing the equipment as well as external standardization of trace element measurement. The zircon standard

91500 (206Pb/238U=1065 Ma) was used for external standardization and the standard zircon GJ–1 was used as a monitoring sample (Wiedenbeck et al., 1995).

ICPMSDataCal software was used for processing the data, and age calculation and concordia diagrams were prepared using Isoplot 3.0 (Ludwig, 2003). Uncertainties for individual analyses are quoted at the 1σ level, and the errors on weighted mean ages are at quoted at 2σ (95% confidence level) (Wang et al., 2015a; Wang et al., 2015b).

Zircon Lu–Hf isotopic analysis was performed at the MLR Key Laboratory of

Metallogeny and Mineral Assessment, using a Neptune laser ablation plasma mass spectrometry. Helium was used as carrier gas of ablation material, the laser beam size was 44μm, and the international GJ1 standard zircon was used as a reference standard.

Related equipment operation conditions and detailed analytical procedures are given in

Hou et al. (2007) and Wang et al. (2016a).

3.4 Fluorite Sm–Nd analyses

Fluorite Sm–Nd isotopic analyses were carried out at the Isotopic Laboratory of

Tianjin Center, China Geologic Survey using a MAT261 thermal ionisation mass spectrometer following procedures given in Peng et al. (2003). The ratios of Sm and

Nd isotopes were corrected using 146Nd/144Nd=0.7219. Sm and Nd contents have an analytical error within 0.5%, and 147Sm/144Nd (2σ) has an error of ±0.5%. The analytical result of standard sample BCR-l is Sm=6.571μg/g，Nd=28.753μg/g, n(143Nd)/n(144Nd)

=0. 512644±0.000005, consistent with the reported values of 6.58 ppm for Sm, 28.8 ppm for Nd (Bell et al., 1989). The decay constant used in the age calculation is

λ147Sm=6.54×10-12/yr. The Sm–Nd isochron ages were calculated with the ISOPLOT compute r program (Ludwig, 2003).

3.5 Stable isotopes (C–O)

Calcite that coexists with fluorite was collected from the northern ore block. The pure calcite separates were prepared for the carbon and oxygen isotope analysis at the

Analytical Laboratory Beijing Research Institute of Uranium Geology. The isotopic compositions were measured following the detailed procedures outlined by Cao et al.

(2015). Dry sample powder of calcite was reacted with 100% H3PO4 at 50 ℃ for approximately 3 h. After the digestion was complete, the CO2 was recovered and cryogenically trapped in liquid nitrogen traps (–195 ℃). All of the non–condensable gases produced in the reaction were pumped out to a vacuum of at least 100 mtorr. The trapped CO2 was then cryogenically transferred to a sample flask and sealed for analysis.

The trapped CO2 was analyzed on a Finnigan MAT–253 isotope ratio mass spectrometer for the carbon and oxygen isotope compositions, with analytical precisions of ±0.2‰ for the C isotopes and ±2‰ for the O isotopes. The δ13C and δ18O

18 values are reported relative to Pee Dee Belemnite (PDB), as follows: δ OSMOW =

18 1.03091 × δ OPDB + 30.91 (Coplen et al., 1983).

4 Analytical results

4.1 Major, trace, and rare earth elements

Major element data on the granite porphyry are given in Table 2.1 which show high SiO2 with limited variation ranging from 78.07% to 79.34% (average of 78.8%).

The content of Na2O+K2O is high and ranges from 4.94% to 7.44% with an average of

5.64%. The ratio of K2O/Na2O varies from 15.5 to 90.86, and Al2O3 varies from 10.8% to 12.16%. The A/CNK ratio ranges from 1.28 to 2.09 and A/NK ratio ranges from 1.33 to 2.18, suggesting aluminium supersaturation (Fig. 2.4a) and display typical Si– enriched, K-enriched and Ca-depleted signature. The SiO2–K2O classification diagram shows that the rocks belong to high–K calc-alkaline series (Fig. 2.4b).

Trace elements and REE analytical results of granite, fluorite, quartz and calcite are given in Table 2.2. The granite has ∑REE varying from 35.9 to 83.7 ppm with an average of 49.6 ppm, LREE/HREE ratio of 1.02 to 3.59 (average of 2.0) and (La/Yb)N of 0.53- 2.26. Eu is depleted and δEu ranges between 0.02 and 0.1 (average 0.05). The

LILEs, like Rb, U and Th are strongly enriched and high field-strength elements

(HFSEs) like Nb, Ta and Ti are relatively depleted in the granite (Fig. 2.5). The negative anomalies of Ba, Sr and Eu possibly indicate a separation of plagioclase and hornblende during the crystallization and fractionalization of granite magma. The geochemical composition of the Herimu Tai granite displays A-type signature, with their plots falling within the field of A-type granite as shown in the Zr–10000×Ga/Al, Nb–10000×Ga/Al,

(K2O+Na2O/CaO)–10000×Ga/Al and TFeO/MgO–10000×Ga/Al diagrams (Fig. 2.6).

2.5 a b 8

2 Peraluminous Shoshonite 6 association

1.5

A/ NK A/ 4

O mass % mass O High-K

2 K 1 Medium-K Peralkaline 2 Low-K 0.5 0 0.50 1.00 1.50 2.00 45 50 55 60 65 70 75 80 85 A/CNK SiO2 mass% Fig. 2.4 Geochemical discrimination diagrams of A/CNK versus A/NK (a; after Maniar and Piccoli,

1989), SiO2 versus K2O (b; after Peccerillo and Taylor, 1976) for the Herimu Tai granite.

1000 1000

100 100

10 10

1 1

0.1

Rock/Chondrite Rock/Primitive Rock/Primitive Mantle

0.1 0.01 La Ce Pr NdSmEu Gd Tb Dy Ho Er TmYb Lu Rb Th Nb K Ce Pr Nd Sm Hf Ti Dy Er Lu Ba U Ta La Pb Sr P Zr Eu Tb Y Yb Fig. 2.5 Chondrite-normalized REE patterns and primitive mantle-normalized spider diagrams for the Herimu Tai granite. (Normalization values are from Sun and McDonough, 1989)

1,000 100

100 A-Type A-Type

- Nb/10 I, S, M-Type Zr/10 10

I, S, M-Type

1 10 1 10 1 10 10000*Ga/Al 10000*Ga/Al

100

A-Type A-Type

10 O)/Cao

2 10

O+Na 2

I, S, M-Type TFeO/MgO I, S, M-Type (K

1 1 1 10 1 10 10000*Ga/Al 10000*Ga/Al

Fig. 2.6 Geochemical classification of the Herimu Tai granite (after Whalen et al, 1987).

Compared with the Herimu Tai granite, the average contents of trace elements and

REEs of single minerals (fluorite, quartz and calcite) are much lower (Table 2.2). The

∑REE varies greatly in individual minerals, and is high in calcite (Fig. 2.7a) and low in quartz (Fig. 2.7b). The ∑REE shows marked variation in different stages of fluorite

(Fig. 2.7c), which is similar to that of other hydrothermal fluorite deposits

(Constantopoulos, 1988). In calcite, the content of ∑REE ranges from 25.0 to 87 ppm

(average of 53.4 ppm), LREEs are relatively enriched, LREE/HREE ratio varies between 2.45 and 6.27 and LaN/YbN ratio averages 8.88. In quartz, the average content of ∑REE is 4.0 ppm, LREE/HREE differentiation is weak, LaN/YbN ratio averages 2.54,

Eu negative anomaly is present and δEu value averages 0.65. In the early-stage fluorite sample (ST–F08, ST–F09 and ST–F10), the ∑REE varies between 5.8 and 68.5 ppm, with an average of 36.2 ppm; in the late-stage fluorite sample (ST–F11 and ST–F12), the ∑REE average is 1.5 ppm, which is markedly lower than that of the early-stage fluorite. The fluorite samples of various stages have nearly consistent REE patterns, a weak positive Eu anomaly and an average δEu value of 1.13. The fluorite, quartz and

calcite show a weak negative Ce anomaly.

100 100 Calcite a Quartz b

ST-Q01 ST-Q02 ST-Q03 ST-Q04 10 10 ST-Q05

1 1

ST-C01 ST-C02

Rock/Chondrite Rock/Chondrite ST-C03 ST-C04

0.1 0.1 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

100 1000 Fluorite c Wall rocks near the ore d

100 10

Rock/Chondrite 1 sedimentary rocks

ST-F08 ST-F09 Rock/Chondrite granitoids ST-F10 ST-F11 0.1 0.1 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu La Ce Pr NdSmEu Gd Tb DyHo Er TmYb Lu

Fig. 2.7 Chondrite-normalized REE patterns for the calcite (a), quartz (b), fluorite (c) and wall rocks

(d) from the Shuitou fluorite deposit. (Normalization values are from Sun and McDonough, 1989,

Data of wall rocks are from Cao et al., 2014)

4.2 Zircon U–Pb Ages

Zircon grains in the samples show columnar habit, with a long axis diameter of 50

- 100 μm and length/width ratio ranging from 1:1.2 to 1:3. Their CL imaging display typical oscillatory zoning (Fig. 2.8a). Results of zircon U–Pb isotopic analysis are listed in Table 2.3, which show Th and U contents in the range of 485 to 1374 and 1218 to

2909 ppm, with Th/U ratios (0.36 - 0.52) exceeding 0.1, indicating a magmatic origin.

Among the analytical data, 9 points fall on or adjacent to the concordia (Fig. 8b) with

spot ages in the range of 135.9 to 137.8 Ma, and weighted mean age of 136.9±1.7 Ma

(n=9, MSWD=1.2), representing the emplacement time of the granite.

Fig. 2.8 (a) CL images of zircon, (b) Zircon U–Pb concordia diagrams and weighted mean model ages for the Herimu Tai granite.

4.3 Zircon Hf Isotopes

Zircon grains which were analysed for U–Pb isotopes were selected for Hf isotope analysis; location of the analytical points is shown in Fig. 2.8a. Point ELMT–04–2 was eliminated due to signal loss. The Hf isotope analysis data of other points are listed in

Table 2.4. The 176Hf/177Hf varies between 0.282723 and 0.282833, and the calculated

εHf(t) show positive values ranging between 1.0 and 4.9 with an average of 2.8 for corresponding age of 136.9 Ma, similar to those of late Mesozoic granites in the Great

Xing'an Range (Fig. 2.9). The single-stage Hf model ages (TDM) range between 631 and

794 Ma and the two-stage model ages (TDM2) range between 877 and 1123 Ma. The fLu/Hf values vary between -0.95 and -0.90, and are lower than the fLu/Hf value (-0.34;

Amelin et al., 2000) of mafic crust and fLu/Hf (-0.72; Vervoort and Jonathan Patchett,

1996) of sialic crust. Therefore, the two-stage model age can better reflect the time of source material extraction from depleted mantle or the average retention age of source

materials in the crust.

30 southern Great Xing'an Range the Herimu Tai granite 20

） t

（ Chondrite

0 εHf

-10 Zircon Zircon

-20

-30 100 125 150 175 200 225 250 275 300 U-Pb Age(Ma)

Fig. 2.9 Ages of zircons vs. εHf (t) values diagram (Vervoort et al., 1996) for the Late Mesozoic granitoids in the southern Great Xing'an Range, data sources: Herimu Tai granites after this study; other granitiods after Guo et al., 2009; Mei et al., 2015; Wu et al., 2011a; Zeng et al., 2015; Zhou et al., 2012; Zhou et al., 2015b; Yang et al., 2014b.

4.4 Fluorite Sm and Nd Isotopic Compositions

The Sm and Nd isotopic compositions of the fluorite samples are listed in Table

2.5. The content of Sm in seven fluorite samples varies between 0.2346 and 1.7331 ppm, the content of Nd varies from 0.1461 to 4.4510 ppm, the ratio of 147Sm/144Nd varies between 0.2274 and 0.3712, and the ratio of 143Nd/144Nd varies between

0.512728 and 0.512851. In 147Sm/144Nd-143Nd/144Nd diagram (Fig. 2.10) the fluorite samples display obvious linear distribution, and the isochron age obtained is 132±11

Ma with mean square of weighted deviates (MSWD) as 0.047, The 143Nd/144Nd initial ratio is 0.512531±0.000023, and the correspondent εNd(t) value is 1.3.

0.51288

0.51284

Nd 0.51280 144

Nd/ 0.51276

143 Age = 132±11 Ma Initial 143Nd/144Nd 0.51272 =0.512531±0.000023 MSWD = 0.047 0.51268 0.18 0.22 0.26 0.30 0.34 0.38 0.42 147Sm/144Nd

Fig. 2.10 Sm–Nd isochron of fluorites from the Shuitou deposit.

4.5 C–O Isotopic compositions

The C–O isotopic composition of four calcite samples collected from the northern

13 ore block of the Shuitou fluorite deposit is listed in Table 2.6. The δ CV-PDB in the

18 calcite varies between -7.1‰ and -6.3‰ (average -6.73‰) and δ OV-SMOW varies between -2.8‰ and -0.7‰ (average -1.75‰). The C and O isotopic compositions are relatively homogenous in the calcite.

4.6 Fluid inclusions

Zeng et al. (2013) and Zhang et al. (2014b) have investigated the fluid inclusions from the northern and central ore blocks of the Shuitou fluorite deposit (Table 2.7). In the present study, I focused on fluid inclusions of fluorite samples collected from the southern ore block. Inclusions in fluorite from this area are evenly distributed, including as groups and within growth zones. The primary inclusions which occur isolated were selected for analysis. Three types of inclusions were observed: 1) pure liquid inclusions

(L type), 2) liquid inclusions (W type), with a gas/liquid ratio of less than 50%, are the

dominant type; their long axis diameters are generally around 10 - 30 μm and this type homogenizes to liquid, 3) gaseous inclusions (V type), with a gas/liquid ratio of 50% -

90%; most of these inclusions were homogenized to liquid after heating, and a few to vapor. The fluorite of early stage has homogenization temperatures clustering around

173.3℃ - 189.9℃ and that of a late stage has lower homogenization temperatures mainly clustered around 155℃ - 173.2℃. At these temperatures, rocks are in a brittle state under hydrostatic pressure (Fournier, 1999), and therefore the temperature and pressure corrections are not required (Bodnar and Bethke, 1984). The trapping pressure of the inclusions were calculated to be 0.9 - 1.7 MPa based on phase diagram. The densities of the inclusions were calculated using standard formula (e.g., Liu and Duan,

1987), and range between 0.791 and 0.923g/cm3, with an average of 0.891g/cm3, indicating low-density fluid. Laser Raman spectroscopic analysis indicate that the vapor and liquid compositions of the inclusions are dominated by H2O, along with minor C3H6 (Fig. 2.11), which are consistent with the composition of inclusions from the northern and central ore blocks.

Fig. 2.11 Laser Raman spectra of fluid inclusions within the fluorites from the Shuitou deposit. (a and c): vapor phases, (b and d): liquid phases. 5 Discussion

5.1 Timing of magmatism and fluorite mineralization, and tectonic setting

The fluorite samples used for dating in this study were collected from fresh ores of the mineralization stage. In the 147Sm/144Nd–143Nd/144Nd diagram, the data show linear correlation with low MSWD values, therefore the isochron age of 132±11 Ma is taken to represent the formation age of the fluorite deposit. The Herimu Tai granite intruded in the southern part of the study area and the zircon U–Pb LA-ICP-MS data from this intrusion yield an age of 136.9±1.7 Ma. The early Cretaceous age is close to the mineralization age of the fluorite. During late Paleozoic, the Siberian Craton collided and amalgamated with the North China Craton following the closure of the

Paleo–Asian Ocean (Han et al., 2015; Jian et al., 2010). During the Mesozoic,

lithospheric extension prompted large-scale intermediate to felsic magmatic activities

(Jahn et al., 2004b; Wang et al., 2015d). The Herimu Tai granite was formed during this structural stage.

The geochemical features of the Herimu Tai intrusion classify it as a high-K calc- alkaline rock enriched in SiO2, Rb, Th, U and Pb, and depleted in Al2O3, TiO2, CaO,

Na2O, Ba, Sr, and P. The REE distribution displays an obvious negative Eu anomaly.

The Nb–Ta and Zr–Hf relations have been employed as a useful tool to trace the magma sources (e.g., Dostal and Chatterjee, 2000; Green, 1995; Liu et al., 2017; McCulloch and Gamble, 1991). The Nb/Ta (6.65–10.86, average: 9.48) and Zr/Hf (16.56 - 23.79, average: 19.75) ratios of the intrusion are closer to those in the crust (11.4 and 33, respectively) than primitive mantle (17.8 and 37, respectively). The Hf isotope systematics are widely used for investigating continental crust growth and recycling

(e.g., Condie and Aster, 2013, Wang et al., 2016a; Yang et al., 2016b). The zircon εHf(t) values in our study show positive values in a restricted range of 1.0 to 4.9, suggesting that juvenile materials were predominant. A compilation of data from Jurassic–early

Cretaceous granites in the central- southern Great Xing'an Range shows that the εHf(t) values mostly fall between the chondrite evolution line and the depleted mantle evolution line (Fig. 2.9). The majority of the granitoids in the CAOB showed positive

εNd(t) values with young two-stage Nd model age (usually less than 1.0 Ga) (Li et al.,

2014c and references therein). I therefore infer that the Herimu Tai granite was probably derived from partial melting of juvenile crustal sources. The two-stage model age (TDM2) shows an average of 1006 Ma correlating with the significant crustal accretion event in

the area during Meso–Neoproterozoic. Mesozoic magmatism occurred widely in the

Great Xing'an Range with voluminous volcanic–plutonic rocks occupying 75% of the area (Shao et al., 2005). This a large-scale magmatism has been correlated to lithospheric thinning and asthenospheric upwelling in the eastern China (Menzies et al.,

1993; Zhang et al., 2009b). The Herimu Tai granite, characterized by high Si values, high alkali concentrations, high Ga/Al ratios and poor Al, Sr, Eu, Ba and Ti values, shows typical A-type signature (Whalen et al., 1987; Wang et al., 2016c). In the

Ga×10000 vs Zr, Ga×10000 vs Nb, Ga×10000 vs (K2O+Na2O)/CaO and Ga×10000 vs.

(TFeO)/MgO plots (Fig. 2.6), the granite samples indicate A-type affinity, with a minor group falling in the transitional field of A- to I-type granites, suggesting that their source materials might have involved metamorphosed igneous protoliths. In Y–Nb–Ce and Y–

Nb–Ga×3 diagrams (Fig. 2.12), the rocks fall in the A2 type field, indicating a post- orogenic setting (Eby, 1992).

Nb Nb

A1 A1

A2 A2

Y Ce Y 3Ga

Fig. 2.12 Discrimination diagrams of tectonic setting of the Herimu Tai granite (after Eby, 1992),

A1, anorogenic granite, A2, post-orogenic granite.

As described by Wu et al. (2002), A-type granites are widely distributed in NE

China, indicating an extensional tectonic setting. The Mesozoic large-scale mineralization is closely related to regional magmatic and tectonic events in the central southern Great Xing'an Range (Mao et al., 2005). Ouyang et al. (2015) performed statistical analysis of the ages of magmatic rocks and the main metal deposits in the central southern Great Xing'an Range, and their results show that the ages of large-scale rock-forming and ore-forming events in the area mainly concentrate between 145 and

120 Ma and the peak of metallogeny is slightly younger than the peak of magmatism.

The ages of magmatic rocks in the southern Shuitou fluorite deposit and the Shuitou fluorite deposit fall within the regional magmatic and mineralization stage. Although the fluorite deposits in the Southern Great Xing'an Range are of lower degree, this area has abundant fluorite resources (Wang et al., 2015c; Zou et al., 2012). Our field investigations revealed that Linxin region and surroundings (such as Ongniud Banner and Aohan Banner) have similar fluorite mineralization with identical geological characteristics where fluorite occurs as veins which are mainly controlled by NE– trending structures, consistent with the outcrop characteristics of late Jurassic–early

Cretaceous magmatic rocks (Wu et al., 2011a; Zhang et al., 2010). Available ages for fluorite deposits in the Southern Great Xing'an Range and its periphery include those of Sumochagan fluorite deposit at 137.6–141 Ma and Yixian fluorite deposit in

Liaoning at 154±28 Ma. I infer that fluorite deposits, regional magmatic rocks and the metallic mineralization are all related to the same tectonic setting within post-collisional extension and are part of the regional mineralization event in the CAOB.

5.2 Nature and evolution of ore fluids

The correlation between magmatism and fluorite mineralization in the region remains controversial, and two contrasting models have been proposed: 1) the ore- forming fluids were derived from a post-magmatic hydrothermal fluid, and the deposits are of magmatic-hydrothermal (e.g., Xu et al., 2009); and 2) the ore-forming fluid was mainly sourced from meteoric water and the deposits are of hydrothermal vein-type

(e.g., Zeng et al., 2013). Variations in fluid density are particularly important with respect to mechanisms of fluid flow (Wilkinson, 2001). Fluid inclusion data on fluorite from the southern ore block in the study area are comparable with previous data on the northern and central ore blocks. The low homogenization temperatures (140℃ - 220℃), salinities (0.27wt.% NaCl eqv - 2.8 wt.% NaCl eqv) and densities (0.86 - 0.891g/cm3) of the fluid inclusions imply that the ore-forming fluids of the fluorite deposit are low salinity ore-bearing hydrothermal fluids, possibly through mixing with meteoric water

(Kendrick et al., 2002). From the early to the late stage, the homogenization temperatures and salinities of the fluid inclusions from the three ore blocks show decrease (Table 2.7), comparable to typical epithermal deposits (e.g., Rossetti and

Colombo, 1999). Lattice-textured quartz and bladed calcite are taken as indicators of fluid boiling (Simmons and Browne, 1998; Simmons and Christenson, 1994) which is a common feature of epithermal mineral systems (e.g., Canet et al., 2011; Simmons et al., 2005). The narrow range of homogenization temperatures, salinities and densities of fluid inclusions correlate the ore-forming fluids of the fluorite deposit to low salinity, low density NaCl–H2O system.

The laser Raman spectroscopic data indicate that the fluid phase is dominated by

H2O. Previous investigations on the bulk inclusion composition based on mass spectrometric analysis indicate H2O fraction up to 95.5% - 98. 8% (Zhang et al., 2014b).

Minor C3H6 and other organic components are also present, but these components easily decompose at a high temperature, and only volatiles in residual magma or post- magmatic hydrothermal fluids cannot generate inclusions containing organic components (Zhang et al., 2006). Therefore, the existence of organic components in the fluorite inclusions of Linxi area suggests that the fluorite was formed in a relatively closed, medium-low temperature system. The organic components in the inclusions might have been derived from the sedimentary strata. The fluorite deposits are mostly hosted by granite and its inner and outer contact zones, with only minor occurrence in volcanic–sedimentary rocks (Zhang et al., 1996). The Y and Ho contents commonly show similar geochemical behavior and therefore the Y/Ho ratio is usually used as a significant parameter for tracing fluid processes (e.g., Deng et al., 2014; Jiang et al.,

2006; Xu et al., 2012). Veklser et al. (2005) proposed that Y is more enriched than Ho in the presence of F-rich liquids, with Y/Ho > 28. Although the fluorite, quartz and calcite samples from the Shuitou fluorite deposit show significant variation in REE contents, their Y/Ho ratios vary over a narrow range as follows: fluorite: 31.7 to 40.0; quartz: 35.1 to 45.2; calcite: 38.6 to 43.2. Plots in Y/Ho-La/Ho diagram (Fig. 2.13), suggest a common origin (Bau and Dulski, 1995).

1000 1.E-05 Early stage fluorite Later stage fluorite Pegmatitic Quartz A Calcite 1.E-06 100 Hydrothermal

1.E-07 B

atom atom ratio Y/Ho

migration Tb/Ca 1.E-08 Sedimentary Early stage fluorite C Later stage fluorite recrystallisation Calcite 1 1.E-09 1 10 100 0.01 0.1 1 La/Ho Tb/La atom ratio Left: Fig. 2.13 Plot of Y/Ho vs. La/Ho for fluorite, calcite and quartz from the Shuitou deposit

(modified after Bau and Dulski, 1995).

Right: Fig. 2.14 Tb/Ca vs. Tb/La diagram for fluorite and calcite from the Shuitou deposit. Trends are taken from Möller et al., 1976.

The Tb/Ca-Tb/La variation can effectively discriminate the genetic type of fluorite, calcite and other Ca-bearing minerals (Deng et al., 2014; Graupner et al., 2015; Möller et al., 1976). The calcite and early-stage fluorite mainly fall within the field of hydrothermal deposits, whereas the late-stage fluorite falls within the sedimentary origin field (Fig. 2.14). The fluorite mainly displays a weak Eu positive anomaly and weak Ce negative anomaly, suggesting low oxygen fugacities and low temperature during fluorite deposition (Constantopoulos, 1988; Ghaderi et al., 1999; Schwinn and

Markl, 2005). In Fig. 2.7, it can be observed that the late stage fluorite contains lower

REE content than fluorite of early stage. This phenomenon could be explained as follows: 1) less compatibility in crystal structure under lower temperatures, 2) lower total REE concentrations in the fluids in late stage, which means the ore-forming fluids during late stage have been diluted by meteoric waters (Assadzadeh et al., 2017). In the northern ore block, calcite coexists with fluorite, both of which cut across as bands or

veins. The calcite precipitated from a hydrothermal system is generally rich in LREE

(Zhong and Mucci, 1995). The calcite in this study shows LREE enrichment. Oxygen, carbon, and hydrogen isotope compositions have been used to constrain the sources of the fluids (e.g., Ripp et al., 2016). The C–O isotopes in the calcite indicate that the ore- forming fluids were principally sourced from meteoric water (Fig. 2.15), which is consistent with the conclusion from fluorite H–O isotopic study from the central ore block (Zhang et al., 2014b). The C–H–O stable isotopes of the fluorite/calcite in the study area indicate that the ore-forming fluids were principally sourced from meteoric water.

10 Marine carbonate 5 Meteori Magmatic 0 water c ） -5 Low temperature altered

PDB -10 （

-15 Mantle C‰

13 -20 δ

-25 Sedimentary organic matter -30 Calcite

-35 -5 0 5 10 15 20 25 30 δ18O‰ (SMOW) Fig. 2.15 δ18O versus δ13C diagram of calcites from the Shuitou deposit. The fields are after Liu et al., 2007.

The REE patterns are commonly used to trace the source of ore-forming elements.

The REE pattern of fluorite differs significantly from that of ore-hosting sedimentary strata and granites in the periphery of the deposit area (Fig. 2.7), suggesting that the

REEs in fluorite were not totally derived from Mesozoic sedimentary rocks and granites.

Considering the solubility and possible sources of F as well as the age of the mineralization, these fluids would have originated during lithospheric thinning, which

was caused by the upwelling of the asthenosphere under continental extension in eastern China (Zhai et al., 2014a). This extensional tectonic setting on a regional scale with the F probably derived from a mantle source (Partey et al., 2005) was favorable for the formation of the fluorite deposits (Rubinstein and Zappettini, 2015). Ca was possibly derived from ore-hosting wallrocks. The ore-forming fluids are a NaCl–H2O fluid system of medium to low temperature, low salinity and low intensity, which is different from the magma-sourced fluids. By combining with the ore-forming fluids and REE characteristics, I infer that the F-rich fluids in this region might have experienced a long-distance migration. Magmatic rocks in the area provided the heat source for the ore-forming fluids, which is similar to the case of with the El Hammam fluorite deposit in Morocco (Bouabdellah et al., 2010) and some of IOCG deposits

(Barton and Johnson, 1996).

5.3 Mechanism of fluorite mineralization

5.3.1 Precipitation mechanism

Five possible precipitation mechanisms of fluorite have been recognized as follows.

(1) Two hot brines of different compositions mix, or hot ore-bearing fluids mix with cool surface water. Microthermometry and laser Raman spectroscopy of fluid inclusions from the Shuitou deposit indicate homogeneous ore-forming fluids.

Therefore, mixing of two fluids of different compositions might not be the dominant mechanism for fluorite precipitation in the Shuitou deposit (Richardson and Pinckney,

1984; Ruiz et al., 1988).

(2) Cooling of low-pH, high-salinity ore-bearing fluids (Deloule, 1982). The fluid inclusions in fluorite in our study have low salinity, and the ore-forming fluids indicate relatively low temperatures in the range of 140℃ to 220℃; thus, cooling might not have been the major factor that triggered fluorite precipitation.

(3) The solubility of CaF2 decreases due to pressure decrease, leading to the precipitation of fluorite. The amount of fluorite precipitated from a dilute solution due to pressure variation is lower by one order of magnitudes than that of fluorite formed through decrease in temperature. In a hydrostatic pressure system, the variation of solubility caused by pressure decreasing is very small (Richardson and Holland, 1979b), and therefore pressure change was not the main factor that contributed to the fluorite precipitation in this region.

(4) Carbonates decompose in ore-hosting wallrocks and CO2 is added into the

+ + fluids, causing MgF complex to form MgHCO3 and CaF2 (Spirakis and Heyl, 1995).

Since large amount of dolomite and other Mg-bearing minerals were not observed within the study area, the decomposition of MgF+ complex was not the cause for fluorite precipitation.

(5) Water/rock reaction between F-rich fluids and ore-hosting wallrocks. The reaction of ore-forming fluid and wallrocks leads to variation of pH in the fluids, particularly when the pH value of the ore-forming fluids turned from acidic to intermediate. This water/rock reaction has been considered as one of the potential causes of fluorite precipitation (Constantopoulos, 1988; Richardson and Holland,

1979a, b). Silification, kaolinization and other alteration processes suggest that the ore-

forming fluids of this deposit were acidic and oxidized (Robb, 2005). When pH<4, the

+ solubility of CaF2 increases with the decrease in pH. Through water/rock reaction, H in the fluids is continuously consumed, pH increases, F– in CaF+ complex is replaced

- by OH , and the solubility of CaF2 decreases. When pH=4 - 7, the solubility of CaF2 remains stable and very low. Therefore, CaF2 in the fluids is relative stable in an acidic condition, and pH increase would lead to the precipitation of fluorite (Deloule, 1982).

One typical case is the formation of the Bayan Obo rare metal deposit (Ling et al., 2013;

Fan et al., 2016) where F-rich fluids which contain rich LREEs, Nb and other components entered sedimentary carbonatite, resulting in neutral reaction between the acidic F-rich fluids and alkaline carbonatite and leading to the precipitation of rare metals from the fluids and forming large quantities of associated fluorite.

5.3.2 A model for the Shuitou fluorite deposit

I propose a model (Fig. 2.16) for the mineralization of the Shuitou fluorite deposit as follows.

(1) During late Mesozoic, the Linxi area witnessed frequent and intensive tectonic–magmatic events. The granite (136.9±1.7 Ma) coeval with fluorite mineralization in the southern part of the study area is classified as A2-type granite; the regional tectonic setting is inferred as post-orogenic extensional setting associated with the opening of the suture zone between the North China and Siberia Cratons in the Late

Jurassic to Early Cretaceous (Fig. 2.16a).

(2) Faults within extensional structural belts are commonly the channels of fluids for upward migration into shallow crustal levels; normal faults favor the deep

circulation and heating of meteoric water, and nearly coeval magmatism have acted as a heat engine, which could drive the hydrothermal circulation system (as described in

Broom-Fendley et al., 2017).

(3) F-bearing acidic hot fluids migrated vertically towards the shallow surface along fault belts episodically, identical to the seismic pumping model of Sibson (1987).

(4) In the shallow surface, water/rock reaction occurred between the F-bearing fluids and wallrocks, and the fluids extracted Ca from the wallrocks, leading to pH increase, fluorite crystallization, and a series of medium to low temperature wallrock alteration zoning. Thus, the Shuitou deposit can be classified as a fault-controlled, hydrothermal vein-type (Fig. 2.16b).

Fig. 2.16 Schematic illustration depicting the ore-forming processes of the Shuitou fluorite deposit,

Inner Mongolia, China. a: Sketch map showing the tectonic setting at ca. 140-120 Ma. b: Suggested model for the fluorite deposit. 6 Conclusions

(1) The mineralization in the Shuitou fluorite deposit in the southern segment of the Great Xing'an Range polymetallic ore belt is controlled by structural systems such as faults, where the ore bodies mainly occur as veins and lenses. The major part of ore body is discontinuously distributed along N-S direction and extends for over 10 km in

length. The mineralogy is relatively simple with fluorite, quartz and calcite.

(2) The Sm–Nd dating of fluorite yielded an isochron age of 132±11 Ma

(MSWD=0.047), suggesting that the Shuitou deposit was formed during Late Jurassic to Early Cretaceous. The zircon U–Pb age data on the associated Herimu Tai granite to the south of this deposit indicate emplacement at 136.9±1.7 Ma (MSWD=1.2), which is consistent with the ore-formation age. The magmatism is inferred to have provided the heat and fluid input. Geochemical and Hf isotope data on the Herimu Tai granite indicate an extensional setting. The Shuitou fluorite deposit belongs to a major magmatic event and associated polymetallic mineralization in the SGXR in the Late

Mesozoic (i.e. 150 - 120 Ma).

(3) Fluid inclusions in the Shuitou fluorite deposit are mainly liquid-rich H2O inclusions, and the ore-forming fluids belong to NaCl–H2O system with medium-low temperature, low salinity and low density. The main minerals in the deposit (fluorite,

13 quartz and calcite) are of a hydrothermal origin and have a uniform source. The δ CV-

18 PDB–δ OV-SMOW relationship of calcite from the study shows meteoric water origin, indicating that the ore-forming fluids were mainly sourced from heated meteoric water, which is similar to the study results of fluorite H–O isotopes.

(4) Water/rock reaction is possibly the main mechanism of fluorite precipitation and crystallization. The water-rock reaction between the F-rich fluids and wallrocks led to the extraction of Ca in the fluids from wallrocks, increased pH value, and fluorite crystallization. These processes also resulted in a series of medium to low temperature wallrock alteration zoning.

Chapter 3: Nature and genesis of the Xiaobeigou fluorite deposit,

Inner Mongolia, Northeast China: Evidence from fluid inclusions and stable isotopes

1 Introduction

Fluorite can form over a wide range of physico-chemical conditions (Eppinger &

Closs, 1990) and often acts as a paragenetic associated mineral in Sn (-W-Mo), Fe-rare earth elements (REEs)-Nb, and base metal deposits (e.g., Assadzadeh et al., 2017;

Galindo et al., 1994; Piqué et al., 2008; Smolyanskii & Bogomolov, 2011; Yang et al.,

2009). Of these, fluorite epigenetic vein deposits are the main source of fluorine worldwide (Zappettini et al., 2017). Late Mesozoic fluorite vein systems are widespread throughout Eastern China, Southeastern Transbaikalia and Eastern Mongolia (Fang,

2014; Hu et al., 1998; Nie et al., 2008; Smolyanskii & Bogomolov, 2011; Wang et al.,

2015c; Xu & Zhang, 2013). They commonly occur as sets of parallel and offset veins in steep faults and breccia zones and could be classified as the “structure-bound type”

(Dill, 2010). The recently discovered Xiaobeigou fluorite deposit is a typical example of a vein-type deposit.

The Xiaobeigou fluorite deposit is located in the southern part of the Southern

Great Xing'an Range (SGXR) metallogenic belt. According to historical mining records, the proven CaF2 reserve in the northeast and southwest parts of the Xiaobeigou deposit is around 100,000 t, but previous mine workings occurred at very shallow depths.

Recently, a near-surface fluorite-bearing quartz vein that discontinuously extends for 4

km was discovered in the middle part of Xiaobeigou deposit through detailed geological mapping.

Based on geological field investigation and geophysical anomalies delineated by the very-low-frequency electromagnetic method, Pei et al. (2016) mainly focused on the prospecting potential of this district. However, the genesis of the Xiaobeigou deposit remained ambiguous to some extent, which restricted the further exploration and evaluation of its resource potential. One of the key problems of genesis of hydrothermal deposits is elucidation of the origin and nature of the mineralizing fluids (Fawzy, 2017;

Wilkinson, 2001). At present, there are two models for the sources of ore-forming fluids for regional vein-type fluorite deposits: (1) the ore-forming fluids were derived from a post-magmatic hydrothermal fluid and mixed with meteoric water at a late stage (e.g.,

Xu et al., 2008) or (2) the ore-forming fluids were formed in response to amagmatic hydrothermal circulation during regional tectonic extension (Pei et al., 2018; Zeng et al., 2013; Zhang et al., 2014b). The major tool for solving this problem is the combination of analysis of stable isotopes of minerals and detailed studies of fluid inclusions (FIs). In this study, I carried out a systematic analysis of geological, geochemical, microthermometric, and stable isotopic (H–O) properties, to elucidate the genesis and mineralization process for the Xiaobeigou deposit. This study may also contribute to an understanding of the ore-forming process of fluorite vein systems in the region generally.

2 Geological Setting

The SGXR is the area north of the Erlian–Hegenshan fault, south of the Xar Moron

fault, and southwest of the Nenjiang fault. It is situated within the eastern segment of the Central Asian Orogenic Belt (Fig. 3.1a), which is one of the largest Phanerozoic accretionary orogenic systems on Earth (Cawood et al., 2009).

Fig. 3.1 (a) Tectonic sketch map of the Central Asian Orogenic Belt, showing the location of

Northeast China (modified after Safonova & Santosh, 2014); (b) tectonic subdivision of Northeast

China (after Wu et al., 2011a); (c) simplified geological map of the South Great Xing'an Range

(modified after Chu et al., 2001; Ruan et al., 2015).

Multi-stage tectonic-magmatic events have occurred in this region since the

Proterozoic period. During the Paleozoic Era, the bidirectional subduction of the Paleo-

Asian Ocean lithosphere beneath the Siberia and North China cratons influenced the overall architecture and magmatic processes of the whole area (Eizenhöfer et al., 2014;

Pei et al., 2017; Wu et al., 2011a; Zhang et al., 2016b). Subsequently, the region entered an intracontinental orogenic stage resulting from the subduction of the Mongol–

Okhotsk ocean plate (Meng, 2003; Wang et al., 2015d) and the western Pacific Ocean plate (Dong et al., 2014; Sengör & Natal'in, 1996).

The SGXR is one of the important metallogenic belts in NE China (Fig. 3.1b), highlighted by a variety of ore systems, including porphyry Mo-Cu-Au, skarn Fe–Sn-

Pb-Zn, hydrothermal Pb-Zn-Ag, epithermal Ag-Au and vein-type fluorite deposits

(Chen et al., 2017; Mao et al., 2011; Ouyang et al., 2015; Pei et al., 2018; Ruan et al.,

2015; Wu et al., 2011b; Zhai et al., 2014b). The SGXR can be broadly subdivided into four metallogenic zones: (1) Xilinhot–Huolin’guole Ag–polymetallic, (2) Linxi–

Ganzhu’ermiao Sn–Cu–polymetallic, (3) Tianshan Mo–polymetallic, and (4) Tuquan

Cu–polymetallic. Details about the nature and distribution of each zone can be found in Ouyang et al. (2015). In addition, the SGXR has developed into a significant fluorite- producing region. The Linxi district, one of the most important finds of fluorite resources within the SGXR, comprises more than 60 fluorite deposits and occurrences.

Representative deposits include the Shuitou, Xiaobeigou, Baoshan, Sandaoyingzi and

Madaigou fluorite deposits, which share very similar geologic and geochemical features (Cao et al., 2014; Fang et al., 2014; Pei et al., 2018; Zhang et al., 2014b).

The oldest units in the SGXR are Precambrian medium- to high-grade metamorphic basements represented by the Xilinhot complex (Shi et al., 2003). Carboniferous strata are sporadically distributed in the central and southern parts of the region, whereas

Permian volcanic and sedimentary rocks with low metamorphic grades are extensively

distributed over the whole area. These units are unconformably overlain by felsic and related volcanoclastic rocks (Zhang et al., 2010). The Permian and Jurassic weakly metamorphosed volcanic and sedimentary rocks are the main host rocks for several mineral deposits (e.g., Zhai et al., 2014b; Zhang et al., 2017a). Regional structures are dominated by sets of faults trending roughly east-west, northeast, and northwest. These faults act as important boundaries between tectonic blocks, and they control the spatial distribution of intrusive rocks and mineral deposits (Fig. 3.1b and Fig. 3.1c). Granitoids occur widely along the major faults, with the majority formed in three episodes: Early

Paleozoic, Late Paleozoic, and Mesozoic (Shi et al., 2014; Wu et al., 2011a), with formation peaking ca. 155–120 Ma (Ouyang et al., 2015). These granitic rocks are characterized by positive εNd(t) values, low initial 87Sr/86Sr ratios, and young Nd model ages, regardless of their age, genetic type, and tectonic setting, indicating Phanerozoic crustal growth in this region (Hong et al., 2004; Jahn et al., 2000b; Yang et al., 2017).

3 Ore deposit geology

3.1 Wall rocks and structures

The Xiaobeigou deposit (43°52′N, 117°52′E) is located close to Xiaobeigou and

Caojiatun villages, approximately 200 km northwest of Chifeng City, Inner Mongolia,

Northeast China. Stratigraphic units that crop out at the study area are the Permian

Shoushangou, Jurassic Manketouebo and Xinmin Formations, together with

Quaternary outcrops (Fig. 3.2a).

Fig. 3.2 (a) Geological map of the Xiaobeigou fluorite deposit; (b) rose diagram showing vein strike directions.

The Shoushangou Formation, which is widely distributed in the Xiaobeigou area, is mainly composed of greyish green silty-argillaceous slate and greyish white fine sandstone (Fig. 3.3a). The Manketouebo Formation in the south part of the district trends northeast–southwest and consists of crystal fragment tuff (Fig. 3.3b), rhyolite and volcaniclastic rock (Fig. 3.3c). The crystal fragment tuff has a tuffaceous texture with debris crystals of quartz, plagioclase, and K-feldspar (Fig. 3.3d). As shown by drilling, these Jurassic rocks are unconformably overlain by the Shanhougou Formation

(Fig. 3.3e). The Jurassic Xinmin Formation is exposed in the southeastern corner of the map area (Fig. 3.2a) and mainly comprises volcaniclastic rocks (Fig. 3.3f). On the surface at the Xiaobeigou, minor quartz porphyry and rhyolite porphyry veins intrude into the volcanic-sedimentary rocks and are exposed sporadically.

Fig. 3.3 Photographs and photomicrographs of the main rocks and ore veins in the Xiaobeigou deposit. (a) argillaceous slate (Shoushangou Formation); (b) crystal fragment tuff (Manketouebo

Formation); (c) volcaniclastic rock (Manketouebo Formation); (d) micrograph of crystal fragment tuff (crossed polarized light); (e) unconformity between the Peimain and Jurassic rocks; (f) fuchsia volcaniclastic rock (Xinmin Formation); (g) quartz veins in wall rock ; (h) bright purple fluorite veinlets; (i) fluorite + quartz vein in the drill core; (j) fault-hosted oredody dipping steeply; (k) pale green fluorite with massive structure; (l) early stage quartz surrounded by late fluorite; (m) white fluorite ore with high grade; (n) banded fluorite; (o) pyrite sparingly disseminated along the fissures;

(p) galena exclusively found in the wallrocks near vein #7; (q) silicification; (r) chloritization; (s) kaolinization.

Faults and shear fractures are well developed in the ore district, most of which acted as loci for hydrothermal alteration and mineralization. Systematic structural study has not been performed because of the considerable grassland vegetation coverage. To identify the provenances of the ore-controlling faults, the occurrence of 121 sets of mineralized veins were measured across the whole area. As shown in Fig. 3.2b, the two identified main fracture trends are north–northeast and northeast.

3.2 Mineralization and alteration

Silica and/or fluorite veins are ubiquitous over the whole area (Fig. 3.3g-Fig. 3.3i), ranging in width from 0.1 to 6 m and in length from several meters to nearly 4 km. So far, 11 mineralized veins with lengths greater than 100 m have been delineated in the

Xiaobeigou deposit (Fig. 3.2a). Ore veins #1, #2, #8, #9, and #11, which are currently exploited, show a dominant strike direction of 10°–20° and a dip of 65°–85°NW (Fig.

3.3j). These veins are roughly parallel to each other and predominantly contain fluorite and quartz. Vein #2 has an average CaF2 grade of 38% and veins #8 and #9 share similar ore grades, ranging from 28.54% to 44.38% (Pei et al., 2016). Mineralized veins #3, #4,

#5, #6, #7, and #10, which are sub-vertical and nearly north-south trending, are newly

identified. The newly discovered vein #7 (Fig. 3.2a) which is >3.5 km long and 0.5–6 m thick, is expected to be the focus of further detailed exploration and core drilling.

According to limited drilling data, this vein commonly dips 75°–85° to the west, but locally dips to the east steeply.

Based on the observation of the ore fabrics, paragenetic sequences and crosscutting relationships, the ore-forming process in the deposit can be divided into hydrothermal and supergene periods, and the former period can be further divided into early and late stages. Ore mineralogy of the Xiaobeigou deposit is composed essentially of fluorite and quartz (Fig. 3.3k-Fig. 3.3n). Sulfide minerals, such as pyrite and galena, are rare and so far have only been found in subaerial environments near vein #7 (Fig.

3.3p).

Hydrothermal alteration at Xiaobeigou is well developed and distributed symmetrically along the fracture zones. Major alteration minerals are dominated by quartz and also composed of chlorite, kaolinite, sericite, and carbonate. Silicic alteration is characterized by stockworks of quartz veins and are intense near the orebodies (Fig.

3.3q), ranging from ~0.5 m to a maximum of 10 m in thickness, as observed at the surface and in drill cores; these stockworks are closely related to the fluorite mineralization. Chlorite mainly occurs at the contact between the ore-bearing veins and the Jurassic Manketouebo Formation (Fig. 3.3r). Kaolinite, which is pervasive near the surface outcrops of the fluorite-bearing veins, is interpreted as having formed post- mineralization (Fig. 3.3s). It is noteworthy that siliceous and kaolinite alteration can be utilized as indicators of fluorite mineralization (Tu, 1996; Xu et al., 2008).

3.3 Vertical zonation of the orebodies

As a common phenomenon, vertical zonation has occurred in a variety of mineral deposits recognized at early times (e.g., Lang, 1979) and has been widely applied for exploration (Brathwaite et al., 2001; Fulp & Renshaw, 1985; Meinert, 1997; Wang et al., 2010). The orebodies in this mining district exhibit well-developed vertical zonation similar to that demonstrated in the Wuyi fluorite district of Zhejiang Province, Southern

China (Xu et al., 1991; Xu et al., 2013b). The regular vertical sequence is best developed in the largest-scale orebody in this district. Vertically, the orebodies can be divided into three parts: upper, central, and lower.

The uppermost zone of the orebodies, represented by milky white to yellowish white silicified stockwork veinlets and veins, was easily distinguished from the surrounding rocks by its clear and sharp contact (Fig. 3.4a). Anhedral to subhedral quartz crystals are the main constituent of these veins. Frequently, drusy or euhedral quartz with a comb or lattice structure was observed in residual spaces (Fig. 3.4b and

Fig. 3.4c). Rare fluorite usually occurs as isolated grains or as purple fibers hosted by quartz crystals (Fig. 3.4d and Fig. 3.4e). With increasing distance from the exposed parts, the fluorine content of veins gradually increases (Fig. 3.4f), and fluorite-bearing veinlets are more common in the country rocks (Fig. 3.3g). The deeper zone of the vein tends to have a lower silica content. Generally, the fluorite was often not economic or of low grade and concentrated towards the margins of such veins (Fig. 3.3h).

Fig. 3.4 Vertical zoning at the Xiaobeigou deposit. Upper zone: (a) outcrop of silica veins, (b) comb-textured quartz, (c) lattice-textured quartz, (d) fluorite crystal surrounded by quartz, (e) purple acicular fluorite intergrown with white quartz, (f) intergrowth of euhedral fluorite and cryptocrystalline quartz, (g) fluorite stockwork veinlets in wall rock, (h) fluorite mineralization toward margins of fissure vein; Central zone: (i) purple fluorite intergrown with quartz showing higher ore grade than in panel (e), (j) colorless fluorite cutting across early quartz, (k) banded fluorite,

(l) blue fluorite (high grade) in the foothills, (m) massive fluorite with annular structure, (n) calcite vein cutting through fine-grained fluorite.

The width of the orebodies in the central zone is apparently greater than that in the upper zone. In addition, ore grades of the central zone are much higher and thus make this zone most important for mining operations. Fluorite-rich zones of mineralization are often found in the centerlines of the veins. As shown in Fig. 3.5, fluorite mineralization also exhibits lateral zonation, which from the centerline outward

consists of massive fluorite, banded fluorite, brecciated fluorite, and fluorite stockworks (veinlets). The fluorite is characterized by blue or purple color, or colorless in some cases, and is either banded or massive in structure (Figs. 3.4i–m). Minor calcite veins cut across subhedral-euhedral fluorite (Fig. 3.4n).

Fig. 3.5 Illustration and photographs showing lateral zonation of fluorite mineralization in the central zone of the orebody.

Limited drill cores from the regional fluorite district indicated that large-scale orebodies could extend at least 400 m vertically. Due to the limited depth of current mining operations in Xiaobeigou, the properties of the lower zone are not addressed by this investigation.

4 Samples and methodology

More than 50 samples from outcrops, underground tunnels, and drill cores were collected. Twelve polished thin sections were made for petrological and mineralogical

studies. Twenty double-polished thin sections (0.3-0.5 mm thick) of different ore stages were prepared for studies of fluid inclusion microthermometry and subsequent laser

Raman spectroscopy. A total of 24 fluorite and quartz specimens were selected in a transect across the ore veins for trace element and stable isotope studies. Fluorite and quartz separation (>99% purity) was done at Langfang Chengxin Geological Services

Co., Ltd. (Hebei, China).

Fluid inclusion petrography and microthermometric measurements were conducted with a Linkam MDSG 600 cooling-heating stage associated with a Zeiss

Axioskop 40 microscope at the State Key Laboratory of Geo-Processes and Mineral

Resources, China University of Geosciences (Beijing). The analysis accuracy for the measured temperatures was constrained with an error of ±0.1 °C and ±1 °C at temperature ranges of −100 to 25 °C and 25 to 400 °C, respectively.

After microthermometric study, laser Raman spectroscopic analysis of individual

FIs was performed using a Renishaw System–2000 microscopic confocal laser Raman spectrometer at the Key Laboratory of the Institute of Mineral Resources, Chinese

Academy of Geological Sciences. Operating conditions included a laser excitation wavelength of 514.5 nm, a laser power of 20 mW and a minimum laser beam diameter of 1 μm. The spectral range and resolution were 100–4,500 cm-1 and 1–2 cm-1, respectively. The analytical method and procedure were similar to those previously described in detail by Burke (2001) and Zou et al. (2016).

Chemical compositions of fluorite and quartz were analyzed using inductively- coupled plasma mass spectrometry (ELEMENT XR ICP-MS, Germany) at the

Analytical Laboratory, Beijing Research Institute of Uranium Geology. The analytical precision of ICP-MS data was better than 5% for most trace elements and 10% for Zr,

Hf, Nb and Ta. The analytical methods were similar to those described by Wang et al.

(2016b).

Three quartz samples and nine fluorite samples from different paragenetic stages were selected for the study of H–O isotope geochemistry at the Analytical Laboratory,

Beijing Research Institute of Uranium Geology. Oxygen isotopes in quartz samples were analyzed using a MAT-253 stable isotope ratio mass spectrometer following the

BrF5 method (Clayton et al., 1972). The oxygen isotopic compositions of water were extracted from the FIs hosted by fluorite. Hydrogen isotopes of FIs hosted by fluorite and quartz were determined for the same samples measured for oxygen isotopes. The experimental procedures were described by Cao et al. (2017b) and Ni et al. (2017).

Results of the H–O isotopic analyses obtained were normalized with the Vienna

Standard Mean Ocean Water standards. The analytical precisions of the O and H isotopes were better than ±2‰ and ±1‰, respectively.

5 Analytical results

5.1 Mineral Geochemistry

Trace element compositions and calculated parameters of nine fluorite samples

(XF1–XF9) and three quartz samples (XQ1–XQ3) are provided in Table 3.1. The REE compositions and distributions of hydrothermal vein minerals have notable variation

(Lottermoser, 1992). The fluorite samples had an average total REE content (∑REE) of

15.82 ppm. In contrast, the ∑REE values for quartz samples did not exceed 0.5 ppm.

The Y contents in the fluorite assay were 4–30.6 ppm, and in the quartz assay were

0.02–0.41 ppm, displaying variations similar to those of REEs. From these data, the

(∑REE+Y) values for quartz are notably lower than those for fluorite. Furthermore, fluorite samples shared similar and relatively flat chondrite-normalized REE patterns

(Fig. 3.6), but they showed variable REE concentrations. The REE contents of the fluorite grains from different ore stages exhibited a decreasing trend, with ∑REE values of 16.14–30.21 ppm for the early fluorites (XF1–XF5) and 3.84–5.76 ppm for the later fluorites (XF6–XF9). Similar observations were also reported for many other fluorite deposits (e.g., Deng et al., 2014; Pei et al., 2018; Souissi et al., 2013). The Eu/Eu* values decreased from early fluorites (1.21–1.96) to later fluorites (1.00–1.28), indicating slightly to moderately positive Eu anomalies. No pronounced Ce anomaly was observed, and the Ce/Ce* ratios ranged between 0.88 and 0.99.

Fig. 3.6 Chondrite-normalized REE patterns for the fluorite samples in the Xiaobeigou deposit. Normalization values are from McDonough and Sun (1995).

5.2 Fluid inclusions

5.2.1 Petrography

Fluid inclusions were widespread in the fluorite and quartz samples. Based on the phases present at room temperature, phase transitions during heating and cooling, and

the results of laser Raman spectroscopy, the FIs can be categorized as three major types: pure liquid single-phase (PL-type), liquid rich two-phase (L-type), and vapor rich two- phase (V-type).

(i) PL-type. The PL-type FIs often occurred in clusters or were distributed randomly with other FI types in fluorite. These FIs were usually less than 5 μm in diameter and were regarded as secondary in origin. Inclusions of this type accounted for <10% of the total FIs.

(ii) L-type. The L-type FIs consisted of vapor bubbles and liquid phases at room temperature, and they had variable vapor phase proportions (2–50 vol%). These inclusions, which accounted for approximately 90% of the observed FIs, were present at all stages and were all homogenized into a liquid phase. They were generally 10–25

μm in size, with elliptical, polygonal, or elongated shapes.

(iii) V-type. The V-type FIs were rare and restricted to early-stage quartz. Compared to L-type FIs, the V-type FIs had higher vapor phase volumetric proportions (>50%).

The inclusions were elliptical or irregular, generally measured 20–40 μm, and homogenized into the vapor phase when heated.

5.2.2 Microthermometry

Microthermometric determinations were undertaken on primary two phase FIs from the fluorite and quartz samples. Microthermometric results for 80 FIs from different stages are presented in Table 3.2 and Fig. 3.7. Salinities (reported in wt% NaCl eqv.) were calculated from ice-melting temperatures (Tm, ice) using the equations of

3 Bodnar (1993) for the NaCl–H2O system. Calculations of densities (g/cm ) were based

on the equation of Liu and Duan (1987).

Fig. 3.7 Histograms of homogenization temperatures and salinities of the FIs from different stages.

The early-stage quartz and fluorite contained abundant L-type FIs and scattered V- type FIs. Homogenization temperatures for L-Type FIs in quartz ranged from 159.5 to

260.7 °C (mainly 200 to 240 °C), with corresponding salinities of 0.18–1.20 wt% NaCl eqv. The obtained final ice-melting temperatures varied from -0.7 to -0.1 °C, with calculated densities of 0.78 to 0.92 g/cm3. Most L-type FIs in fluorite yielded slightly lower homogenization temperatures of 138.1 to 266.8 °C (peaking at 160–200 °C) and ice-melting temperatures of -0.5 to -0.1 °C, which correspond to salinities of 0.18–0.88 wt% NaCl eqv. and densities of 0.77–0.93 g/cm3. One fluid inclusion showed much lower ice-melting temperatures of -4.8 °C, corresponding to a salinity of 7.59 wt% NaCl

eqv. V-type FIs were only observed in the early-stage quartz and showed similar homogenization temperatures but different homogenization paths (homogenization to vapor phase).

Late-stage FIs were dominated by the L-type. A total of 49 FIs showed a relatively narrow range of ice-melting temperatures from -0.8 to -0.1 °C, with corresponding salinities of 0.18–0.88 wt% NaCl eqv. These FIs homogenized to the liquid phase at

132.5–245.8 °C, with the majority at approximately 160−180 °C. The calculated densities varied in a small range, from 0.80 to 0.94 g/cm3.

5.2.3 Composition of fluid inclusions

Laser Raman spectroscopy was carried out to constrain the compositions of the L- type FIs from different stages. Representative laser Raman spectra are shown in Fig.

3.8. Both the liquid and gaseous components of the early-stage FIs were dominated by

H2O. In the late-stage FIs, the vapor and liquid compositions were primarily H2O with minor amounts of organic components. These organic compounds were only detected

−1 in two FIs with a sharp peak at 1,296 cm for the CH2 species (Atamas et al., 2004;

Bower & Maddams, 1989). No CO2 was identified in any stage FIs by laser Raman spectroscopy, which agrees with the absence of carbonic phases in the microthermometric measurements.

Fig. 3.8 Representative Raman spectra of the FIs in the Xiaobeigou deposit. (a) vapor phase and (b) liquid phase composition of L-type FIs in quartz; (c) vapor phase and (d) liquid phase composition of L-type FIs in late-stage fluorite. Qtz = Quartz; Fl = Fluorite.

5.3 Hydrogen and oxygen isotopic systematics

Hydrogen and oxygen isotopic analyses were conducted on the samples used for

18 trace element study. The H–O isotopic compositions and calculated δ OH2O for three quartz samples are summarized in Table 3.3 and Fig. 8.9. The δD values for early-stage

18 quartz samples were between -139.4‰ and -131.6‰, while the δ OV–SMOW values were

18 between 3.0‰ and 4.2‰, corresponding to calculated δ OH2O values for water in equilibrium with quartz ranging from -7.5‰ to -6.3‰. The fluorite samples in different

18 stages shared relatively similar H-O isotopic compositions. They yielded δ OH2O and

δD values of -6.0‰ to -2.6‰ and -121.9‰ to -102‰, with averages of -4.7‰ and -

18 117.4‰, respectively, slightly larger than the δ OH2O and δD values for quartz samples.

Metamorphic

-40 water ‰

H2O -80 Primary

δD magmatic water

Shuitou fluorite deposit -120 Quartz Fluorite -160 -20 -10 0 10 20 30 18 δ OH2O ‰ Fig. 3.9 Hydrogen- and oxygen isotopic compositions of the Xiaobeigou deposit. Field of Shuitou fluorite deposit is from Zhang et al. (2014b); fields of primary magmatic water and metamorphic water are from Taylor (1974). 6 Discussion

6.1 Nature and evolution of the ore-forming fluid

As described above, vertical zonation is well developed at Xiaobeigou, and quartz is the main mineral in the upper part of the ore bodies. Hence, the early-stage quartz could provide the earliest record of ore fluids. The coexistence of the L-type and V-type

FIs in quartz, in conjunction with typical comb, crustiform, and lattice textures, suggest that mineralization occurred in an open system under low pressures and temperatures

(Akaryali, 2016; Hagemann et al., 1994). Petrographic studies showed that the FIs in the early-stage quartz and fluorite were mainly L-type. According to microthermometric data, the ore fluids were characterized by low temperatures (~160–

240°C), low salinities (0.18–1.20 wt% NaCl eqv.), and low densities (0.77–0.94 g/cm3).

Laser Raman spectroscopy identified only H2O in the liquid and gaseous phases of the

FIs. Hence, the ore-forming fluid in the early stage belongs to an H2O–NaCl system.

In the late stage, the fluid was further cooled, corresponding to the observed low homogenization temperatures (mainly 160−180 °C). However, the FIs showed similar low salinities within a narrow range of 0.18–0.88 wt% NaCl eqv. compared to those in the early stage. In general, there is a positive homogenization temperature versus salinity correlation when fluid mixing occurs (Wilkinson, 2001; Zhong et al., 2017). As shown in Fig. 3.10, this trend is not observed, implying that the fluid source may have been homogenous. Laser Raman spectroscopy showed that the phase components of the FIs were dominated by H2O. In addition, minor FIs contained organic compounds, which is also consistent with the composition of FIs in the Shuitou fluorite deposit near the Xiaobeigou deposit (Pei et al., 2018). The Permian mudrocks that act as the main wall rocks of the fluorite deposits show good hydrocarbon resource potential in this region, as reported by Zhang et al. (2013). The existence of organic constituents may result from the water/rock reaction, which is conducive to the precipitation of fluorite

(Constantopoulos, 1988). Thus, the ore-forming fluid of the late stage also belongs to an H2O−NaCl system.

5.0 Early stage quartz

4.0 Early stage fluorite Late stage fluorite

3.0

2.0

1.0 Salinity (wt% NaCl eqv.) Salinity(wt%

0.0 0 100 200 300 400 500 Th (℃) Fig. 3.10 Homogenization temperatures versus salinities for FIs from different stages.

The REE geochemistry can also be used to determine the nature and evolution of a hydrothermal fluid in fluorite deposits (Bau et al., 2003; Mondillo et al., 2016).

Fluorite often shows significant variation in the REE composition in hydrothermal deposits (e.g., Schwinn & Markl, 2005), and the fluid composition is an important controlling factor for REE behavior (Morgunov & Bykova, 2009). Regardless of the

∑REE values for the fluorites from different stages, they shared similar chondrite- normalized REE patterns, indicating a homogenous fluid system. As noted in Section

5.1, total concentrations of REE in late-stage fluorite are lower than those in early-stage fluorite. Several possible scenarios (e.g., fractional crystallization, fluid mixing, and temperature changes) can produce this phenomenon (see the discussion in Assadzadeh et al., 2017). Considering the nature of the fluid investigated above and the only slight temperature difference, we argue that different-stage fluorites were precipitated from a single hydrothermal fluid system. At the early stage, ore fluid contained relatively high

REE concentrations. After the precipitation of the early fluorite, residual fluid subsequently could have been depleted in REE, which resulted in lower concentrations in the later fluorite.

The Eu3+/Eu2+ redox potential of hydrothermal fluids depends on the environmental conditions (mainly temperature); therefore, Eu anomalies can be a useful indicator of the crystallization temperature (Bau & Dulski, 1995; Castorina et al., 2008).

Fluorite crystallized at temperatures lower than 200°C typically shows no or a slightly positive Eu anomaly (Möller et al., 1998). All analyzed fluorite samples irrespective of ore stages showed a positive Eu anomaly (Eu/Eu* = 1.00–1.96), which probably

indicates that crystallization took place at temperatures below 200 °C. This is also consistent with the microthermometric results for most measured FIs.

Therefore, the ore-forming fluids of the Xiaobeigou deposit belonged to a low- temperature (160 to 240 °C), low-salinity (0.18–1.20 wt% NaCl eqv.), and low-density

3 (0.77 to 0.94 g/cm ) H2O–NaCl system.

6.2 Sources of the ore-forming fluids

Stable isotopes are principally used as isotopic tracers to examine the ultimate source of the H2O in hydrothermal fluids (Hayashi et al., 2000; Taylor, 1997; Zhang et

18 al., 2017b). The obtained δD and δ OH2O values for ore-forming fluids ranged from -

139.4‰ to -102.0‰ and -7.5‰ to -2.6‰, respectively, which are all meteoric water dominated and significantly different from those of metamorphic water and magmatic

18 water compositions (Taylor, 1974, 1997). In the δ OH2O versus δD diagram, all the H–

O isotopic data points fall close to the meteoric water line and values obtained for the

Shuitou fluorite deposit (Zhang et al., 2014b), possibly with no input of magmatic components. This deduction is also supported by the absence of CO2-bearing FIs, as well as the prevalence of L-type FIs at Xiaobeigou. Furthermore, the low δD values are within the range of Mesozoic meteoric water in the Great Xing’an Range (-140 to -

90‰; Zhang, 1985). Also, the meteoric water origin of the ore fluids is further supported by the low temperatures, low salinities, and low densities of the FIs, and the open space-filling textures.

In summary, based on stable isotopic data and FI studies, I infer that the ore fluids in this deposit are unambiguously of meteoric water origin.

6.3 Ore genesis and tectonic setting

Ore-forming fluid studies showed that fluorite-bearing veins were deposited by hydrothermal solutions characterized by a low-temperature and low-salinity H2O–NaCl system. In addition, Y and Ho often show similar geochemical behavior and their fractionation is controlled by the nature of the fluid rather than the source (Bau & Dulski,

1995; Veksler et al., 2005). As shown in the Y/Ho–La/Ho diagram (Fig. 3.11a), the

Y/Ho ratios for the quartz and fluorite were within a narrow range from 28.7 to 47.1.

Meanwhile, the La/Ho ratio for early-stage fluorite is slightly higher than that for late- stage fluorite, suggesting that these minerals share a common origin and that recrystallization occurred in late hydrothermal stages (Bau & Dulski, 1995). Tb/Ca-

Tb/La ratios can effectively discriminate the genetic type of fluorite (Möller et al.,

1976). In the Tb/Ca–Tb/La diagram (Fig. 3.11b), the early-stage fluorites are plotted in the hydrothermal field, and the late-stage fluorites are plotted close to the boundary between hydrothermal and sedimentary fields, implying that water/rock reaction occurred especially during the late stage.

1000 1.E-05 a Pegmatitic b Early stage fluorite Later stage fluorite Quartz 1.E-06 100 Hydrothermal

1.E-07

atom ratio Y/Ho 10 migration Tb/Ca 1.E-08 Sedimentary Early stage fluorite recrystallisation Late stage fluorite 1 1.E-09 1 10 100 0.01 0.1 1 La/Ho Tb/La atom ratio Fig. 3.11 Diagrams of (a) Y/Ho versus La/Ho and (b) Tb/Ca versus Tb/La for fluorite and quartz samples from the Xiaobeigou deposit (modified after Bau and Dulski, 1995; Möller et al., 1976).

To constrain the timing of fluorite mineralization in the Linxi district, Cao et al.

(2013) conducted electron spin resonance dating on coeval quartz from these typical vein-type deposits, and the obtained ages ranged from 157 to 126 Ma, with an average of ~137 Ma. Of these, one sample collected from the south part of the Xiaobeigou deposit yielded an age of 126 ±15 Ma. This is also concordant with the Sm–Nd age

(132 ±11 Ma) of the Shuitou fluorite deposit (Pei et al., 2017). Consequently, I infer that the Xiaobeigou deposit formed during the Late Mesozoic. During this period, tectonic extension occurred over the whole SGXR, and accordingly extensive magmatism and related mineral deposits were generated (Ouyang et al., 2015). It is worth noting that although the contribution of the input of magmatic fluids is negligible according to our study, coeval magmatism might have provided the power to drive the hydrothermal circulation system which is similar to the situation described by Broom-

Fendley et al. (2017), Pei et al. (2017) and Zappettini et al. (2017).

In summary, the fluorite veins are fault-controlled and deposited from ore fluids that belonged to a low-temperature, low-salinity and low-density H2O–NaCl system.

The Xiaobeigou fluorite deposit, as well as other fluorite deposits in the Linxi district, was formed under the extensional tectonic regime during the Late Mesozoic.

7 Conclusions

(1) Hydrothermal veins are ubiquitous in the Xiaobeigou deposit and predominantly contain fluorite and quartz. The orebodies in this mining district exhibit a well-developed vertical zonation and could be divided into upper, central, and lower zones. Fluorite mineralization in the upper zone is often not economic, but it provides

important clues for exploration. The silica contents of the vein tend to be lower in the deeper zone. The central zone is the most important site for mining operation, with a high ore grade. In the fluorite-rich zones, mineralization also exhibits lateral zonation.

(2) Fluid inclusion and trace element studies indicated that the ore-forming fluids may have been derived from an H2O–NaCl system with low temperature, low salinity, and low density. Hydrogen and oxygen isotope ratios suggest that the ore fluids in this deposit originated from meteoric water.

(3) The Xiaobeigou deposit is fault-controlled and can be classified as a typical hydrothermal vein-type fluorite deposit. Combined with regional data, I infer that the

Xiaobeigou deposit formed during the Late Mesozoic in an extensional setting.

Chapter 4: Conclusions

Located at the Xing’an-Mongolia segment of the Central Asian Orogenic Belt, the

Linxi fluorite district is situated in a superposition area caused by the Paleo-Asia tectonic-metallogenic domain and the Western Paleo-Pacific tectonic–metallogenic domain. However, some key issues such as mineralization age, nature of the ore- forming fluids and hydrothermal processes linked to fluorite mineralization remain ambiguous. In this contribution, based on a systematic investigation of representative fluorite deposits (e.g., Shuitou deposit, Xiaobeigou deposit) in the study area, I integrate regional relevant geological, geochronological, geophysical and geochemical information to evaluate the ore-forming processes. In conclusion, this study obtained the following achievements and innovations:

(1) Fluorite vein systems are widespread throughout the Linxi district and they

commonly occur as sets of parallel and offset veins in steep faults and breccia

zones. The fluorite deposits share similar geologic features and are mainly of

structure-related hydrothermal vein-type. It is no selectivity for fluorite

mineralization to wall rocks, which mainly include volcanic-sedimentary

rocks (Permian and Jurassic) and granodiorites (Triassic) and granites

(Jurassic). Ore bodied are mainly controlled by NNE-trending structures and

commonly occur as veins and lenses. Ore mineralogy of fluorite deposits are

composed essentially of fluorite and quartz. Wall rock alterations are

dominated by sets of medium-low temperature hydrothermal alterations.

(2) The orebodies in this mining district exhibit a well-developed vertical zonation

and could be divided into upper, central, and lower zones. Fluorite

mineralization in the upper zone is often not economic, but it provides

important clues for exploration. The silica contents of the vein tend to be lower

in the deeper zone. The central zone is the most important site for mining

operation, with a high ore grade. In the fluorite-rich zones, mineralization also

exhibits lateral zonation.

(3) The Sm-Nd isochron age of fluorites from Shuitou deposit is 132±11 Ma,

combined with the obtained ages of the typical fluorite deposits from the Linxi

district, indicating that the major mineralization stage occurred during early

Cretaceous. The widespread fluorite vein systems in this region are closely

link to the period of tectonic transfer in northeast Asian which is characterized

by the transformation from NNE-trending contraction to NNE-trending

extension during the early Cretaceous. Subsequent regional extension and

lithosphere thinning occurred, which triggered widespread fluorite

mineralization in this region.

(4) Homogenization temperatures and salinities of the fluid inclusions mainly

range from 140 to 240 °C and 0.27~2.8 wt.% NaCl eqv, respectively. The

calculated densities show average value of ~0.88 g/cm3. Laser Raman spectra

show that both the vapor and liquid compositions of the inclusions are

18 dominated by H2O. The δ O H2O-SMOW and δD H2O-SMOW values obtained from

fluid inclusions in quartz and fluorite of the Shuitou and Xiaobeigou deposits

range from -6.7‰ to +2.3‰ and -115.5‰ to -140.1‰, respectively. The

13 coexisting calcite from the Shuitou deposit has δ CV-PDB varying from -7.1‰

18 to -6.3‰ (average -6.73‰) and δ OV-SMOW from -2.8‰ to -0.7‰. The C-H-

O isotopic features suggest that the ore-forming fluids are of meteoric water origin. Furthermore, Latitude effect on δD values of the fluorite deposits in the

Eastern China was mentioned in this contribution. The ore-forming fluids can be mainly attributed to NaCl-H2O system with moderate to low temperature, low salinity and low density. There is no evidence for post-magmatic hydrothermal fluid. The ore-forming fluid shows a meteoric water source, with water-rock reaction as the main mechanism for fluorite precipitation. The water-rock reaction between the F-rich fluids and wallrocks led to the extraction of Ca in the fluids from wallrocks, increased pH value, and fluorite crystallization.

Acknowledgements

At the outset, I would like to express my deepest gratitude to my two dedicated supervisors, Professor Ken-ichiro Hayashi and Professor Shouting Zhang. I gratefully thank Professor Ken-ichiro Hayashi for the great support and assistance and caring throughout all my years in University of Tsukuba. I appreciate the invaluable space for me to do my research and it has been an honor to be his first Chinese Ph.D. student.

Professor Shouting Zhang not only have taught me how excellent fieldwork and experiment is done beyond the textbooks but also treat me as an extended part of his family. I am extremely appreciative of his tremendous academic and financial support.

Besides my supervisors, I would also express thanks to Professor Toshiaki

Tsunogae and Professor Ken-ichiro Hisada for their support, encouragement and guidance during my stay in Japan. I also want to thank Associate Professor Komuro

Kosei for the thoughtful discussions. My sincere thanks must also go to the members of planetary resource geology group and office room 113 for their care and precious friendship.

I give my sincere thanks to Associate Professor Changming Wang, Professor M.

Santosh, Professor Franco Pirajno, Professor Robert Stern, Associate Professor Zhang

Yongmei for their fruitful comments and suggestions.

In particular, I would like to thank Bozhi Fu for her mother-like care given to me.

A very special thank goes to Dr. Huawen Cao who cared so much about my work and

inspired me over the years.

I am greatly indebted to the organizations who have supported my work on this research: University of Tsukuba, China University of Geosciences, Chinese Academy of Geological Science, Analytical Laboratory Beijing Research Institute of Uranium

Geology, Tianjin Institute of Geology and Mineral Resource, Langfang Honesty

Geological Services Co., Ltd. (China) and Beijing GeoAnalysis Co., Ltd. (China).

This work is financially supported by the Fundamental Research Funds for the

Central Universities (No. 2652015398 & No. 2652017277), Geological Survey project of China Geological Survey (No. 1212011220925), the National Science of the 12th

‘‘Five-Year Technology Support Program’’ (Grant No. 2011BAB04B06), Science and

Technology project of Linxi county people's government (Inner Mongolia, China; No.

2-7-2011-04), Innovation Fund of the China University of Geosciences (Beijing) and the award of the China Scholarship Council (No. 201706400008).

Finally, I would like to express my very profound gratitude to my beloved parents, brother and close friends for their continued support and generous care.

References

Akaryali, E. 2016. Geochemical, fluid inclusion and isotopic (O, H and S) constraints

on the origin of Pb–Zn ± Au vein-type mineralizations in the Eastern Pontides

Orogenic Belt (NE Turkey). Ore Geology Reviews. 74, 1-14.

Amelin, Y., Lee, D.-C., Halliday, A.N., Pidgeon, R.T., 1999. Nature of the Earth's

earliest crust from hafnium isotopes in single detrital zircons. Nature. 399, 252-

255.

Amelin, Y., Lee, D.C., Halliday, A.N., 2000. Early-middle Archaean crustal evolution

deduced from Lu–Hf and U–Pb isotopic studies of single zircon grains. Geochim.

Cosmochim. Acta. 64, 4205-4225.

Assadzadeh, GE, Samson, IM, Gagnon, JE. 2017. The trace element chemistry and

cathodoluminescence characteristics of fluorite in the Mount Pleasant Sn-W-Mo

deposits: Insights into fluid character and implications for exploration. Journal of

Geochemical Exploration. 172, 1-19.

Atamas, N.A., Yaremko, A.M., Seeger, T., Leipertz, A., Bienko, A., Latajka, Z.,

Ratajczak, H. and Barnes, A.J. 2004. A study of the Raman spectra of alkanes in

the Fermi-resonance region. Journal of Molecular Structure. 708, 189-195.

Bao, Q., Zhang, C., Wu, Z., Wang, H., Li, W., Sang, J., Liu, Y., 2007. SHRIMP U-Pb

Zircon Geochronology of a Carboniferous Quartz-Diorite in Baiyingaole Area,

Inner Mongolia and Its Implications. Journal of Jilin University. 37, 15-23 (in

Chinese with English abstract).

Bau, M. and Dulski, P. 1995. Comparative study of yttrium and rare-earth element

behaviours in fluorine-rich hydrothermal fluids. Contributions to Mineralogy and

Petrology. 119, 213-223.

Bau, M., Romer, R.L., Luders, V. and Dulski, P. 2003. Tracing element sources of

hydrothermal mineral deposits: REE and Y distribution and Sr-Nd-Pb isotopes in

fluorite from MVT deposits in the Pennine Orefield, England. Mineralium

Deposita. 38, 992-1008.

Barbarin, B., 1999, A review of the relationships between granitoid types, their origins

and their geodynamic environments. Lithos. 46, 605-626. Blichert-Toft, J.,

Albarède, F., 1997. The Lu-Hf isotope geochemistry of chondrites and the

evolution of the mantle-crust system. Earth and Planetary Science Letters. 148,

243-258.

Barker, S.L.L., Bennett.C., Cox, S.F., Norman, M.D., Gagan, M.K., 2009. Sm–Nd, Sr,

C and O isotope systematics in hydrothermal calcite–fluorite veins. Implications

for fluid–rock reaction and geochronology. Chemical Geology. 268, 58-66.

Barton, M.D., Johnson, D.A., 1996. Evaporitic-source model for igneous-related Fe

oxide–(REE–Cu–Au–U) mineralization. Geology. 24, 259-262.

Bau, M., Dulski, P., 1995. Comparative study of yttrium and rare-earth element

behaviours in fluorine-rich hydrothermal fluids. Contributions to Mineralogy and

Petrology. 119, 213-223.

Bell, K., Anglin, C.D., Franklin, J.M., 1989. Sm–Nd and Rb-Sr isotope systematics of

scheelites: Possible implications for the age and genesis of vein-hosted gold

deposits. Geology. 17, 500-504.

Blichert-Toft J and Albarède F. 1997. The Lu-Hf isotope geochemistry of chondrites

and the evolution of the mantle-crust system. Earth and Planetary Science Letters.

148, 243-58.

Bodnar, R.J. 1993. Revised equation and table for determining the freezing point

depression of H2O-NaCl solutions. Geochimica et Cosmochimica Acta. 57, 683-

684.

Bonin, B., 2007. A-type granites and related rocks. Evolution of a concept, problems

and prospects. Lithos. 97, 1-29.

Bower, D. and Maddams, W. 1989. The vibrational spectroscopy of polymers.

Cambridge Universtiy Press, pp. 1-271.

Bodnar, R.J., Bethke, P.M., 1984. Systematics of stretching of fluid inclusions; I,

Fluorite and sphalerite at 1 atmosphere confining pressure. Economic Geology. 79,

141-161.

Bouabdellah, M., Banks, D., Klugel, A., 2010. Comments on "A late Triassic

(40)Ar/(39)Ar age for the El Hammam high-REE fluorite deposit (Morocco):

mineralization related to the Central Atlantic Magmatic Province?" by Cheilletz et

al. (Mineralium Deposita 45:323-329, 2010). Mineralium Deposita. 45, 729-731.

Brathwaite, R.L., Cargill, H.J., Christie, A.B. and Swain, A. 2001. Lithological and

spatial controls on the distribution of quartz veins in andesite- and rhyolite-hosted

epithermal Au–Ag deposits of the Hauraki Goldfield, New Zealand. Mineralium

Deposita. 36, 1-12.

Broom-Fendley S, Brady AE, Wall F, Gunn G, Dawes W. 2017. REE minerals at the

100

Songwe Hill carbonatite, Malawi: HREE-enrichment in late-stage apatite. Ore

Burke, E.A.J. 2001. Raman microspectrometry of fluid inclusions. Lithos, 55, 139-158.

Cao, H.-H., Xu, W.-L., Pei, F.-P., Wang, Z.-W., Wang, F., Wang, Z.-J., 2013, Zircon U–

Pb geochronology and petrogenesis of the Late Paleozoic–Early Mesozoic

intrusive rocks in the eastern segment of the northern margin of the North China

Block. Lithos. 70–171, 191-207.

Canet, C., Franco, S.I., Prol-Ledesma, R.M., González-Partida, E., Villanueva-Estrada,

R.E., 2011. A model of boiling for fluid inclusion studies: Application to the

Bolaños Ag–Au–Pb–Zn epithermal deposit, Western Mexico. Journal of

Geochemical Exploration. 110, 118-125.

Cao, H., Zhang, S., Gao, Y., Zeng, Z., Gao, F., Wang, G., Zou, H., 2014. REE

Geochemistry of Fluorite from Linxi Fluorite Deposit and its Geological

Implications, Inner Mongolia Autonomous Region. Geochimica 43, 131-140 (in

Chinese with English abstract).

Cao, H., Zhang, S., Zou, H., Fang, Y., Zhang, P. and Wang, G. 2013, ESR dating of

quartz from Linxi fluorite deposits, Inner Mongolia and its geological implications.

Geoscience, 27, 888-894 (In Chinese with English abstract).

Cao, H.W., Zhang, S.T., Santosh, M., Zheng, L., Tang, L., Li, D., Zhang, X.H., Zhang,

Y.H., 2015. The Luanchuan Mo–W–Pb–Zn–Ag magmatic–hydrothermal system

in the East Qinling metallogenic belt, China: Constrains on metallogenesis from

C–H–O–S–Pb isotope compositions and Rb–Sr isochron ages. Journal of Asian

Earth Sciences. 111, 751–780.

101

Cao, H.-W., Zhang, Y.-H., Pei, Q.-M., Zhang, R.-Q., Tang, L., Lin, B., Cai, G.-J., 2017a,

U–Pb dating of zircon and cassiterite from the Early Cretaceous Jiaojiguan iron-

tin polymetallic deposit, implications for magmatism and metallogeny of the

Tengchong area, western Yunnan, China. International Geology Review. 59, 234-

258.

Cao, H.W., Pei, Q.M., Zhang, S.T., Zhang, L.K., Tang, L., Lin, J.Z., Zheng, L., 2017b,

Geology, geochemistry and genesis of the Eocene Lailishan Sn deposit in the

Sanjiang region, SW China. Journal of Asian Earth Sciences. 137, 220-240.

Canet, C., Franco, S.I., Prol-Ledesma, R.M., González-Partida, E., Villanueva-Estrada,

R.E., 2011. A model of boiling for fluid inclusion studies: Application to the

Bolaños Ag–Au–Pb–Zn epithermal deposit, Western Mexico. Journal of

Geochemical Exploration. 110, 118-125.

Castorina, F., Masi, U., Padalino, G. and Palomba, M. 2008. Trace-element and Sr–Nd

isotopic evidence for the origin of the Sardinian fluorite mineralization (Italy).

Applied Geochemistry. 23, 2906-2921.

Cawood, P.A., Kroner, A., Collins, W.J., Kusky, T.M., Mooney, W.D. and Windley, B.F.

2009, Accretionary orogens through Earth history. Geological Society of London

Special Publications. 318, 1-36.

Chappell, B.W., 1999. Aluminium saturation in I- and S-type granites and the

characterization of fractionated haplogranites. Lithos. 46, 535-551.

Chappell, B.W., Bryant, C.J., Wyborn, D., 2012. Peraluminous I-type granites. Lithos.

153, 142-153.

102

Chappell, B.W., White, A.J.R., 1992. I-and S-type granites in the Lachlan Fold Belt.

Transactions of the Royal Society of Edinburgh. Earth Sciences. 83, 1-26.

Chen, B., Jahn, B.-m., Wilde, S., Xu, B., 2000. Two contrasting paleozoic magmatic

belts in northern Inner Mongolia, China. petrogenesis and tectonic implications.

Tectonophysics. 328, 157-182.

Chen, B., Jahn, B.M., Tian, W., 2009. Evolution of the Solonker suture zone.

Constraints from zircon U–Pb ages, Hf isotopic ratios and whole-rock Nd–Sr

isotope compositions of subduction- and collision-related magmas and forearc

sediments. Journal of Asian Earth Sciences. 34, 245-257.

Chen, C., Liu, Y., Foley, S.F., Ducea, M.N., He, D., Hu, Z., Chen, W., Zong, K., 2016.

Paleo-Asian oceanic slab under the North China craton revealed by carbonatites

derived from subducted limestones. Geology. 44, 1039-1042.

Chen, J., Li, B., Xing, D., Liu, M., Yang, J., Wang, Y., Chen, H., 2015. Zircon U-Pb

ages and geological significance of the plagiclase amphibolite in the Baoyintu

Group Eastern of Chifeng. Geological Survey and Research. 38, 81-88, 99 (in

Chinese with English abstract).

Chen, M., 2011. Chifeng District Fluorite Deposit Metallogenic Characteristics and

Comprehensive Information Metallogenic Prediction Research (Master thesis).

China University of Geosciences, Beijing, pp. 1-69 (in Chinese with English

abstract).

Chen, Y.-J., Pirajno, F., Li, N. and Deng, X.-H. 2017. Molybdenum deposits in China.

Ore Geology Reviews. 81, Part 2, 401-404.

103

Cheng, R., Wu, F., Ge, W., Sun, D., Liu, X., Yang, J., 2006, Emplacement age of the

Raohe Complex in eastern Heilongjiang Province and the tectonic evolution of the

eastern part of Northeastern China. Acta Petrologica Sinica. 22, 353-376 (in

Chinese with English abstract).

Chesley, J.T., Halliday, A.N., Scrivener, R.C., 1991. Samarium-Neodymium Direct

Dating of Fluorite Mineralization. Science. 252, 949-951.

Chu, N.C., Taylor, R.N., Chavagnac., Nesbitt, R.W., Boella, R.M., Milton, J.A.,

German, C.R., Bayon, G., Burton, K., 2002. Hf isotope ratio analysis using multi-

collector inductively coupled plasma mass spectrometry. an evaluation of isobaric

interference corrections. Journal of Analytical Atomic Spectrometry. 17, 1567-

1574.

Chu, X., Huo, W. and Zhang, X. 2001. Sulfur, Carbon and lead isotope studies of the

Dajing polymetallic deposit in Linxi County, Inner Mongolia, China – Implication

for metallogenic elements from hypomagmatic source. Resource Geolog. 51, 333-

344.

Clayton, R.N., O'Neil, J.R. and Mayeda, T.K. 1972. Oxygen isotope exchange between

quartz and water. Journal of Geophysical Research. 77, 3057-3067.

Clemens, J.D., 2003. S-type granitic magmas—petrogenetic issues, models and

evidence. Earth-Science Reviews. 61, 1-18.

Coplen, T.B., Kendall, C., Hopple, J., 1983. Comparison of stable isotope reference

samples. Nature. 302, 236–238.

Condie KC, Aster RC. 2013. Refinement of the supercontinent cycle with Hf, Nd and

104

Sr isotopes. Geoscience Frontiers. 4, 667-80.

Constantopoulos, J., 1988. Fluid inclusions and rare earth element geochemistry of

fluorite from south-central Idaho. Economic Geology. 83, 626-636.

Davis, G.A., Xu, B., Zheng, Y.-D., Zhang, W.-J., 2004. Indosinian extension in the

Solonkersuture zone. The Sonid Zuoqi metamorphic core complex, Inner

Mongolia, China. Earth Science Frontiers. 11, 135-144.

Deloule, E., 1982. The genesis of fluorspar hydrothermal deposits at Montroc and Le

Burc, the Tarn, as deduced from fluid inclusion analysis. Economic Geology. 77,

1867-1874.

Deng, X.-H., Chen, Y.-J., Yao, J.-M., Bagas, L., Tang, H.-S., 2014. Fluorite REE-Y

(REY) geochemistry of the ca. 850 Ma Tumen molybdenite–fluorite deposit,

eastern Qinling, China: Constraints on ore genesis. Ore Geology Reviews. 63,

532-543.

Dill, H.G. 2010. The “chessboard” classification scheme of mineral deposits:

Mineralogy and geology from aluminum to zirconium. Earth-Science Reviews.

100, 1-420.

Dong, Y., Ge, W.-c., Yang, H., Xu, W.-l., Zhang, Y.-l., Bi, J.-h., Liu, X.-w., 2016.

Geochronology, geochemistry, and Hf isotopes of Jurassic intermediate-acidic

intrusions in the Xing’an Block, northeastern China. Petrogenesis and implications

for subduction of the Paleo-Pacific oceanic plate. Journal of Asian Earth Sciences.

118, 11-31.

Dong, Y., Ge, W.c., Yang, H., Zhao, G., Wang, Q., Zhang, Y., Su, L., 2014.

105

Geochronology and geochemistry of Early Cretaceous volcanic rocks from the

Baiyingaolao Formation in the central Great Xing'an Range, NE China, and its

tectonic implications. Lithos. 205, 168-184.

Dos Santos, R.P., Bonhomme, M.G., 1991. K/Ar dating of clays associated with flourite

mineralizations along the Atlantic coast of South America-Relationships with

South Atlantic Ocean Opening. Source, Transport and Deposition of Metals.

Rotterdam, Balkema, Brookfield, 381-384.

Dostal, J., Chatterjee, A.K., 2000. Contrasting behaviour of Nb/Ta and Zr/Hf ratios in

a peraluminous granitic pluton (Nova Scotia, Canada). Chemical Geology. 163,

207-218.

Dong, G., Morrison, G., Jaireth, S., 1995. Quartz textures in epithermal veins,

Queensland; classification, origin and implication. Economic Geology. 90, 1841-

1856.

Eby, G.N., 1990, The A-type granitoids. A review of their occurrence and chemical

characteristics and speculations on their petrogenesis. Lithos. 26, 115-134.

Eby, G.N., 1992. Chemical subdivision of the A-type granitoids. petrogenetic and

tectonic implications. Geology. 20, 641-644.

Eizenhöfer, P.R., Zhao, G., Zhang, J., Sun, M., 2014. Final closure of the Paleo-Asian

Ocean along the Solonker Suture Zone. Constraints from geochronological and

geochemical data of Permian volcanic and sedimentary rocks. Tectonics. 33, 441-

463.

Elhlou, S., Belousova, E., Griffin, W.L., Pearson, N.J., O'Reilly, S.Y., 2006, Trace

106

element and isotopic composition of GJ-red zircon standard by laser ablation.

Geochimica Et Cosmochimica Acta. 70, 407-421.

Eppinger, R.G. and Closs, L.G. 1990. Variation of trace elements and rare earth

elements in fluorite; a possible tool for exploration. Economic Geology. 85, 1896-

1907.

Etoh, J., Izawa, E., Watanabe, K., Taguchi, S., Sekine, R., 2002. Bladed Quartz and Its

Relationship to Gold Mineralization in the Hishikari Low-Sulfidation Epithermal

Gold Deposit, Japan. Economic Geology. 97, 1841-1851.

Fan, H.R., Yang, K.F., Hu, F.F., Liu, S., Wang, K.Y., 2016. The giant Bayan Obo REE-

Nb-Fe deposit, China: Controversy and ore genesis. Geoscience Frontiers. 7, 335-

344.

Fang, Y. 2014. The study of comprehensive exploration methods for the prediction of

concealed fluorite deposit in East China (Ph.D. Thesis). China University

Geosciences (Beijing), Beijing, pp. 1-195 (In Chinese with English abstract).

Fang, Y., Zhang, S., Zou, H., Zhang, P., Zeng, Z. and Gao, F. 2014. Comprehensive

exploration method for fluorite deposits in grasslands covered area: A case study

of the Saiboluogoumen fluorite deposit in Linxi, Inner Mongolia, China. Journal

of Chengdu University of Technology (Science & Technology Edition). 41, 94-

101.

Fawzy, K.M. 2017. The genesis of fluorite veins in Gabal El Atawi granite, Central

Eastern Desert, Egypt. Journal of African Earth Sciences. doi:

10.1016/j.jafrearsci.2017.03.025.

107

Fournier, R.O., 1999. Hydrothermal processes related to movement of fluid from plastic

into brittle rock in the magmatic-epithermal environment. Economic Geology. 94,

1193-1211.

Fulp, S.M. and Renshaw, L.J. 1985. Volcanogenic-exhalative tungsten mineralization

of Proterozoic age near Santa Fe, New Mexico, and implications for exploration.

Geology, 13, 66.

Galindo, C., Tornos, F., Darbyshire, D.P.F., Casquet, C., 1994. The age and origin of

the barite-fluorite (Pb-Zn) veins of the Sierra del Guadarrama (Spanish Central

System, Spain): a radiogenic (Nd, Sr) and stable isotope study. Chemical Geology.

112, 351-364.

Gao, S., Liu, X., Yuan, H., Hattendorf, B., Günther, D., Chen, L., Hu, S., 2002.

Determination of Forty-Two Major and Trace Elements in USGS and NIST SRM

Glasses by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry.

Geostandards and Geoanalytical Research. 26, 181-196.

Gao, X., Guo, F., Xiao, P., Kang, L., Xi, R., 2016. Geochemical and Sr–Nd–Pb isotopic

evidence for ancient lower continental crust beneath the Xi Ujimqin area of NE

China. Lithos. 252–253, 173-184.

Ge, S., Zhai, M., Safonova, I., Li, D., Zhu, X., Zuo, P., Shan, H., 2015. Whole-rock

geochemistry and Sr–Nd–Pb isotope systematics of the Late Carboniferous

volcanic rocks of the Awulale metallogenic belt in the western Tianshan Mountains

(NW China). Petrogenesis and geodynamical implications. Lithos. 228–229, 62-

77.

108

Ge, W.C., Wu, F.Y., Zhou, C.Y., Zhang, J.H., 2005. Zircon U-Pb ages and its

significance of the Mesozoic granites in the Wulanhaote region, central Da

Hinggan Mountain. Acta Petrologica Sinica. 21, 749-762. (in Chinese with English

abstract)

Ghaderi, M., Palin, J.M., Campbell, I.H., Sylvester, P.J., 1999. Rare earth element

systematics in scheelite from hydrothermal gold deposits in the Kalgoorlie-

Norseman region, Western Australia. Economic Geology. 94, 423-437.

Ghani, A.A., Searle, M., Robb, L., Chung, S.-L., 2013. Transitional I S type

characteristic in the Main Range Granite, Peninsular Malaysia. Journal of Asian

Earth Sciences. 76, 225-240.

Graupner, T., Mühlbach, C., Schwarz-Schampera, U., Henjes-Kunst, F., Melcher, F.,

Terblanche, H., 2015. Mineralogy of high-field-strength elements (Y, Nb, REE) in

the world-class Vergenoeg fluorite deposit, South Africa. Ore Geology Reviews.

64, 583-601.

Grebennikov, A.V., 2014. A-type granites and related rocks. Petrogenesis and

classification. Russian Geology and Geophysics. 55, 1074-1086.

Green, T.H., 1995. Significance of Nb/Ta as an indicator of geochemical processes in

the crust-mantle system. Chemical Geology. 120, 347-359.

Griffin, W.L., Pearson, N.J., Belousova, E., Jackson, S.E., van Achterbergh, E.,

O’Reilly, S.Y., Shee, S.R., 2000. The Hf isotope composition of cratonic mantle.

LAM-MC-ICPMS analysis of zircon megacrysts in kimberlites. Geochimica et

Cosmochimica Acta. 64, 133-147.

109

Guo, F., Fan, W., Li, C., Gao, X., Miao, L., 2009. Early Cretaceous highly positive ε

Nd felsic volcanic rocks from the Hinggan Mountains, NE China: origin and

implications for Phanerozoic crustal growth. International Journal of Earth

Sciences. 98, 1395-1411.

Guo, P., Xu, W.-L., Yu, J.-J., Wang, F., Tang, J., Li, Y., 2016. Geochronology and

geochemistry of Late Triassic bimodal igneous rocks at the eastern margin of the

Songnen-Zhangguangcai Range Massif, Northeast China. petrogenesis and

tectonic implications. International Geology Review. 58, 196-215.

Guo, Z.-X., Yang, Y.-T., Zyabrev, S., Hou, Z.-H., 2017. Tectonostratigraphic evolution

of the Mohe-Upper Amur Basin reflects the final closure of the Mongol-Okhotsk

Ocean in the latest Jurassic–earliest Cretaceous. Journal of Asian Earth Sciences.

145, 494-511.

Hagemann, S.G., Gebremariam, M. and Groves, D.I. 1994. Surface-water influx in

shallow-level Archean lode-gold deposits in Western, Australia. Geology, 22,

1067-1070.

Han, G., Liu, Y., Neubauer, F., Jin, W., Genser, J., Ren, S., Li, W., Wen, Q., Zhao, Y.,

Liang, C., 2012. LA-ICP-MS U–Pb dating and Hf isotopic compositions of detrital

zircons from the Permian sandstones in Da Xing’an Mountains, NE China. New

evidence for the eastern extension of the Erenhot–Hegenshan suture zone. Journal

of Asian Earth Sciences. 49, 249-271.

Han, J., Zhou, J.-B., Wang, B., Cao, J.-L., 2015. The final collision of the CAOB:

Constraint from the zircon U–Pb dating of the Linxi Formation, Inner Mongolia.

110

Geoscience Frontiers. 6, 211-225.

Hayashi, K., Maruyama, T. and Satoh, H. 2000. Submillimeter scale variation of oxygen

isotope of vein quartz at the Hishikari deposit, Japan. Resource Geology. 50, 141-

150.

Hofmann, A.W., 1988. Chemical differentiation of the Earth. the relationship between

mantle, continental crust, and oceanic crust. Earth and Planetary Science Letters.

90, 297-314.

Hong, D., Zhang, J., Wang, T., Wang, S., Xie, X., 2004. Continental crustal growth and

the supercontinental cycle. evidence from the Central Asian Orogenic Belt. Journal

of Asian Earth Sciences. 23, 799-813.

Hou, K., Li, Y., Zou, T., Qu, X., Shi, Y., Xie, G., 2007. Laser ablation-MC-ICP-MS

technique for Hf isotope microanalysis of zircon and its geological applications.

Acta Petrologica Sinica. 23, 2595-2604 (in Chinese with English abstract).

Hu, D., Li, Y., Zhan, N., Zhu, Z., Dong, Q., Ma, R., 2015. Very low-grade

metamorphism of the upper Permian Linxi Formation from the southern Da

Xing'an Mountains, NE China. Constraints from clay mineral genesis. Applied

Clay Science. 114, 447-453.

Hu, S., Yan, H., Ye, M. and Xiang, W. 1998. Metallogenic focus-area and superlarge

mineral deposits in the bordering zones between China, Russia and Mongolia.

Science in China Series D: Earth Sciences. 41, 28-36.

Huang, Z., Long, X., Yuan, C., Sun, M., Wang, J., Zhang, Y., Chen, B., 2016. Detrital

zircons from Neoproterozoic sedimentary rocks in the Yili Block: Constraints on

111

the affinity of microcontinents in the southern Central Asian Orogenic Belt.

Gondwana Research. 37, 39-52.

Institute of Geological Survey of China University of Geosciences (Beijing)

(IGSCUGB), Regional Geology of Inner Mongolia Autonomous Region (1.

250,000 Siziwangqi Region). Geological Publishing House, Beijing (in Chinese).

Inner Mongolian Bureau of Geology and Mineral Resources (IMBGMR), 1991.

Regional Geology of Inner Mongolia Autonomous Region. Geological Publishing

House, Beijing (in Chinese).

Jackson, S.E., Pearson, N.J., Griffin, W.L., Belousova, E.A., 2004. The application of

laser ablation-inductively coupled plasma-mass spectrometry to in situ U–Pb

zircon geochronology. Chemical Geology. 211, 47-69.

Jahn, B.-M., Capdevila, R., Liu, D., Vernon, A., Badarch, G., 2004b. Sources of

Phanerozoic granitoids in the transect Bayanhongor–Ulaan Baatar, Mongolia:

geochemical and Nd isotopic evidence, and implications for Phanerozoic crustal

growth. Journal of Asian Earth Sciences. 23, 629-653.

Jahn, B.M., Litvinovsky, B.A., Zanvilevich, A.N., Reichow, M., 2009. Peralkaline

granitoid magmatism in the Mongolian–Transbaikalian Belt: Evolution,

petrogenesis and tectonic significance. Lithos. 113, 521-539.

Jahn, B.M., Griffin, W.L., Windley, B., 2000a, Continental growth in the Phanerozoic.

Evidence from Central Asia. Tectonophysics. 328, vii-x.

Jahn, B.-M., Windley, B., Natal'in, B., Dobretsov, N., 2004a, Phanerozoic continental

growth in Central Asia. Journal of Asian Earth Sciences. 23, 599-603.

112

Jahn, B.M., Wu, F.Y., Chen, B., 2000b, Massive granitoid generation in Central Asia.

Nd isotope evidence and implication for continental growth in the Phanerozoic.

Episodes. 23, 82-92.

Jian, P., Liu, D., Kröner, A., Windley, B.F., Shi, Y., Zhang, F., Shi, G., Miao, L., Zhang,

W., Zhang, Q., Zhang, L., Ren, J., 2008. Time scale of an early to mid-Paleozoic

orogenic cycle of the long-lived Central Asian Orogenic Belt, Inner Mongolia of

China. Implications for continental growth. Lithos. 101, 233-259.

Jian, P., Liu, D., Kröner, A., Windley, B.F., Shi, Y., Zhang, W., Zhang, F., Miao, L.,

Zhang, L., Tomurhuu, D., 2010. Evolution of a Permian intraoceanic arc–trench

system in the Solonker suture zone, Central Asian Orogenic Belt, China and

Mongolia. Lithos. 118, 169-190.

Jiang, Y., Ling, H., Jiang, S., Shen, W., Fan, H., Ni, P., 2006. Trace element and Sr-Nd

isotope geochemistry of fluorite from the Xiangshan uranium deposit southeast

China. Economic Geology. 101, 1613-1622.

Kendrick, M.A., Burgess, R., Pattrick, R.A.D., Turner, G., 2002. Hydrothermal Fluid

Origins in a Fluorite-Rich Mississippi Valley-Type District: Combined Noble Gas

(He, Ar, Kr) and Halogen (Cl, Br, I) Analysis of Fluid Inclusions from the South

Pennine Ore Field, United Kingdom. Economic Geology. 97, 435-451.

Khain, E.V., Bibikova, E.V., Kröner, A., Zhuravlev, D.Z., Sklyarov, E.V., Fedotova,

A.A., Kravchenko-Berezhnoy, I.R., 2002. The most ancient ophiolite of the

Central Asian fold belt. U–Pb and Pb–Pb zircon ages for the Dunzhugur Complex,

Eastern Sayan, Siberia, and geodynamic implications. Earth and Planetary Science

113

Letters. 199, 311-325.

King, P.L., White, A.J.R., Chappell, B.W., Allen, C.M., 1997. Characterization and

Origin of Aluminous A-type Granites from the Lachlan Fold Belt, Southeastern

Australia. Journal of Petrology. 38, 371-391.

Koschek, G., 1993. Origin and significance of the SEM cathodoluminescence from

zircon. Journal of Microscopy. 171, 223-232.

Kröner, A., Kovach., Belousova, E., Hegner, E., Armstrong, R., Dolgopolova, A.,

Seltmann, R., Alexeiev, D.V., Hoffmann, J.E., Wong, J., Sun, M., Cai, K., Wang,

T., Tong, Y., Wilde, S.A., Degtyarev, K.E., Rytsk, E., 2014. Reassessment of

continental growth during the accretionary history of the Central Asian Orogenic

Belt. Gondwana Research. 25, 103-125.

Lang, B. 1979. The base metals-gold hydrothermal ore deposits of Baia Mare, Romania.

Economic Geology. 74, 1336-1351.

Le Maitre, R.W., 2002. Igneous Rocks. A Classification and Glossary of Terms.

Cambridge University Press.

Li, J., Gao, L., Sun, G., Li, Y., Wang, Y., 2007a, Shuangjingzi middle Triassic syn-

collisional crust-derived granite in the east Inner Mongolia and its constraint on

the timing of collision between Siberian and Sino-Korean paleo-plates. Acta

Petrologica Sinica. 23, 565-582. (in Chinese with English abstract)

Li J, Guo F, Li C, Li H, Zhao L. 2014c. Neodymium isotopic variations of Late

Paleozoic to Mesozoic I- and A type granitoids in NE China: Implications for

tectonic evolution. Acta Petrologica Sinica. 30, 1995-2008 (in Chinese with

114

English abstract).

Li, J.Y., 2006. Permian geodynamic setting of Northeast China and adjacent regions.

closure of the Paleo-Asian Ocean and subduction of the Paleo-Pacific Plate.

Journal of Asian Earth Sciences. 26, 207-224.

Li, S., Chung, S.L., Wilde, S.A., Wang, T., Xiao, W.J., Guo, Q.Q., 2016a. Linking

magmatism with collision in an accretionary orogen. Sci Rep. 6, 25751.

Li, S., Wang, T., Wilde, S.A., Tong, Y., 2013a. Evolution, source and tectonic

significance of Early Mesozoic granitoid magmatism in the Central Asian

Orogenic Belt (central segment). Earth-Science Reviews. 126, 206-234.

Li, S., Wilde, S.A., He, Z., Jiang, X., Liu, R., Zhao, L., 2014a. Triassic sedimentation

and postaccretionary crustal evolution along the Solonker suture zone in Inner

Mongolia, China. Tectonics. 33, 960-981.

Li, S., Wilde, S.A., Wang, T., Guo, Q., 2013b. Incremental growth and origin of the

Cretaceous Renjiayingzi pluton, southern Inner Mongolia, China. Evidence from

structure, geochemistry and geochronology. Journal of Asian Earth Sciences. 75,

226-242.

Li, S., Wilde, S.A., Wang, T., Xiao, W., Guo, Q., 2016b. Latest Early Permian granitic

magmatism in southern Inner Mongolia, China. Implications for the tectonic

evolution of the southeastern Central Asian Orogenic Belt. Gondwana Research.

29, 168-180.

Li, X.-H., Li, Z.-X., Li, W.-X., Liu, Y., Yuan, C., Wei, G., Qi, C., 2007b. U–Pb zircon,

geochemical and Sr–Nd–Hf isotopic constraints on age and origin of Jurassic I-

115

and A-type granites from central Guangdong, SE China. A major igneous event in

response to foundering of a subducted flat-slab? Lithos. 96, 186-204.

Li, Y., Xu, W.-L., Tang, J., Pei, F.-P., Wang, F., Sun, C.-Y., 2018. Geochronology and

geochemistry of Mesozoic intrusive rocks in the Xing'an Massif of NE China:

Implications for the evolution and spatial extent of the Mongol–Okhotsk tectonic

regime. Lithos. 304-307, 57-73.

Li, Y., Zhou, H., Brouwer, F.M., Xiao, W., Wijbrans, J.R., Zhao, J., Zhong, Z., Liu, H.,

2013c. Nature and timing of the Solonker suture of the Central Asian Orogenic

Belt. insights from geochronology and geochemistry of basic intrusions in the

Xilin Gol Complex, Inner Mongolia, China. International Journal of Earth

Sciences. 103, 41-60.

Li, Y., Zhou, H., Brouwer, F.M., Xiao, W., Wijbrans, J.R., Zhong, Z., 2014b. Early

Paleozoic to Middle Triassic bivergent accretion in the Central Asian Orogenic

Belt. insights from zircon U-Pb dating of ductile shear zones in central Inner

Mongolia, China. Lithos. 205, 84-111.

Li, Y., Zhou, H., Brouwer, F.M., Xiao, W., Zhong, Z., Wijbrans, J.R., 2011. Late

Carboniferous–Middle Permian arc/forearc-related basin in Central Asian

Orogenic Belt. Insights from the petrology and geochemistry of the Shuangjing

Schist in Inner Mongolia, China. Island Arc. 20, 535-549.

Ling, M.-X., Liu, Y.-L., Williams, I.S., Teng, F.-Z., Yang, X.-Y., Ding, X., Wei, G.-J.,

Xie, L.-H., Deng, W.-F., Sun, W.-D., 2013. Formation of the world’s largest REE

deposit through protracted fluxing of carbonatite by subduction-derived fluids.

116

Scientific Reports. 3, 1776.

Liu, B., Duan, G., 1987. The Density and Isochoric Formulae for NaCl-H2O Fluid

Inclusions (Salinty≤25 WT%) and Their Applications. Acta Mineralogica Sinica.

7, 345-352 (in Chinese with English abstract).

Liu, C., Wu, C., Zhu, Y., Zhou, Z., Jiang, T., Liu, W., Li, H., 2015. Late Paleozoic–Early

Mesozoic magmatic history of central Inner Mongolia, China. Implications for the

tectonic evolution of the Xingmeng Orogenic Belt, the southeastern segment of

the Central Asian Orogenic Belt. Journal of Asian Earth Sciences. doi.

http.//dx.doi.org/10.1016/j.jseaes.2015.09.011.

Liu, C, Zhou Z, Wu J, Li H, Wu C, Zhu Y, Ye B. 2017a. Geochronology, geochemistry

and tectonic implications of Weitingchagan composite pluton in northern segment

of the Xing-Meng Orogenic Belt. Geological Journal. 52. 900-918.

Liu, H., Li, Y., He, H., Huangfu, P., Liu, Y., 2018. Two-phase southward subduction of

the Mongol-Okhotsk oceanic plate constrained by Permian-Jurassic granitoids in

the Erguna and Xing'an massifs (NE China). Lithos. 304-307, 347-361.

Liu, J., Chi, X., Zhang, X., Zhihong, M.A., Zhao, Z., Wang, T., Zhaochu, H.U.,

University, J., Changchun, 2009. Geochemical Characteristic of Carboniferous

Quartz-Diorite in the Southern Xiwuqi Area, Inner Mongolia and Its Tectonic

Significance. Acta Geologica Sinica. 83, 365-376 (in Chinese with English

abstract).

Liu, J., Zheng, M., Cook, N.J., Long, X., Deng, J., Zhai, Y., 2007. Geological and

geochemical characteristics of the Sawaya'erdun gold deposit, southwestern

117

Chinese Tianshan. Ore Geology Reviews. 32, 125-156.

Liu, S., Gurnis, M., Ma, P., Zhang, B., 2017b. Reconstruction of northeast Asian

deformation integrated with western Pacific plate subduction since 200 Ma. Earth-

Science Reviews. 175, 114-142.

Liu, W., Siebel, W., Li, X.-j., Pan, X.-f., 2005. Petrogenesis of the Linxi granitoids,

northern Inner Mongolia of China. constraints on basaltic underplating. Chemical

Geology. 219, 5-35.

Liu, Y., Hu, Z., Gao, S., Günther, D., Xu, J., Gao, C., Chen, H., 2008. In situ analysis

of major and trace elements of anhydrous minerals by LA-ICP-MS without

applying an internal standard. Chemical Geology. 257, 34-43.

Liu, Y., Jiang, S., Bagas, L., 2016. The genesis of metal zonation in the Weilasituo and

Bairendaba Ag–Zn–Pb–Cu–(Sn–W) deposits in the shallow part of a porphyry Sn–

W–Rb system, Inner Mongolia, China. Ore Geology Reviews. 75, 150-173.

Liu, Y., Nie, F., Liu, Y., Hou, W., 2012a. Zircon SHRIMP U-Pb dating and geological

significance of granite in the Baogeda Ula Mo (W) mining area, Inner Mongolia,

China. Acta Petrologica Sinica. 28, 401-408. (in Chinese with English abstract)

Liu, Y., Wang, X., Wang, D., He, D., Zong, K., Gao, C., Hu, Z., Gong, H., 2012b,

Triassic high-Mg adakitic andesites from Linxi, Inner Mongolia. Insights into the

fate of the Paleo-Asian ocean crust and fossil slab-derived melt–peridotite

interaction. Chemical Geology. 328, 89-108.

Lottermoser, B.G. 1992. Rare earth elements and hydrothermal ore formation processes.

Ore Geol. Rev., 7, 25-41.

118

Ludwig, K.R., 2003. User's Manual for Isoplot 3.00. a Geochronological Toolkit

forMicrosoft Excel. Berkeley Geochronology Center Special Publication.

Luo, Z., Xu, B., Shi, G., Zhao, P., Faure, M., Chen, Y., 2016. Solonker ophiolite in Inner

Mongolia, China. A late Permian continental margin-type ophiolite. Lithos. 261,

72-91.

Ma, A.-Y., 2009. 40Ar/39Ar dating of muscovite in mylonite of ShangGanggangkundui

Fault. New evidence for the main stage of Xar Moron River Fault zone. Xinjiang

Geology. 27, 170-175 (in Chinese with English abstract).

Maniar, P.D., Piccoli, P.M., 1989. Tectonic discrimination of granitoids. Geological

Society of America Bulletin. 101, 635-643.

Mao, J., Pirajno, F., Cook, N., 2011. Mesozoic metallogeny in East China and

corresponding geodynamic settings—An introduction to the special issue. Ore

Geology Reviews. 43, 1-7.

Mao, J., Pirajno, F. and Cook, N. 2011. Mesozoic metallogeny in East China and

corresponding geodynamic settings – An introduction to the special issue. Ore

Geology Reviews. 43, 1-7.

Mao, J., Xie, G., Zhang, Z., Li, X., Zhang, Y., Zhang, C., Li, Y., 2005. Mesozoic Large-

scale Metallogenic Pulses in North China and Corresponding Geodynamic

Settings. Acta Petrologica Sinica. 21, 171-190 (in Chinese with English abstract).

Mazukabzov, A., 2012. Timing and processes of late Mesozoic mid-lower-crustal

extension in continental NE Asia and implications for the tectonic setting of the

destruction of the North China Craton: mainly constrained by zircon U–Pb ages

119

from metamorphic core complexes. Lithos. 154, 315–345.

McCulloch MT, Gamble JA. 1991. Geochemical and geodynamical constraints on

subduction zone magmatism. Earth and Planetary Science Letters. 102, 358-74.

McDonough, W.F., Sun, S.s., 1995. The composition of the Earth. Chemical Geology.

120, 223-253.

Mei, W., Lü, X., Cao, X., Liu, Z., Zhao, Y., Ai, Z., Tang, R., Abfaua, M.M., 2015. Ore

genesis and hydrothermal evolution of the Huanggang skarn iron–tin polymetallic

deposit, southern Great Xing'an Range: Evidence from fluid inclusions and isotope

analyses. Ore Geology Reviews. 64, 239-252.

Meinert, L.D. 1997, Application of skarn deposit zonation models to mineral

exploration. Exploration and Mining Geology. 6, 185.

Meng, Q.-R., 2003. What drove late Mesozoic extension of the northern China–

Mongolia tract? Tectonophysics. 369, 155-174.

Menzies, M.A., Fan, W., Zhang, M., 1993. Palaeozoic and Cenozoic lithoprobes and

the loss of >120 km of Archaean lithosphere, Sino-Korean craton, China.

Geological Society, London, Special Publications. 76, 71-81.

Miao, L., Fan, W., Liu, D., Zhang, F., Shi, Y., Guo, F., 2008. Geochronology and

geochemistry of the Hegenshan ophiolitic complex. Implications for late-stage

tectonic evolution of the Inner Mongolia-Daxinganling Orogenic Belt, China.

Journal of Asian Earth Sciences. 32, 348-370.

Miao, L.C., 2003. SHRIMP Zircon Geochronological Studies of the Da Hinggan

Mountains. Report of the Postdoctoral Research, Institute of Geology and

120

Geophysics, Chinese Academy of Sciences. (in Chinese with English abstract)

Middlemost, Eric A. K., 1994. Naming materials in the magma/igneous rock system.

Earth-Science Reviews. 37, 215-224.

Möller, P., Bau, M., Dulski, P. and Lüders, V. 1998. REE and Y fractionation in fluorite

and their bearing on fluorite formation. Proceedings of the 9th Quadrennial

IAGOD Symp., Schweizerbart, Stuttgart, pp. 575–592.

Möller, P., Parekh, P.P. and Schneider, H.J. 1976. The application of Tb/Ca-Tb/La

abundance ratios to problems of fluorspar genesis. Mineralium Deposita. 11, 111-

116.

Mondillo, N., Boni, M., Balassone, G., Spoleto, S., Stellato, F., Marino, A., Santoro, L.

and Spratt, J. 2016. Rare earth elements (REE)–Minerals in the Silius fluorite vein

system (Sardinia, Italy). Ore Geology Reviews. 74, 211-224.

Morgunov, K.G. and Bykova, V.G. 2009. Thermodynamic modeling of the REE

distribution between fluorite and ore-forming fluid in postmagmatic deposits in

western Transbaikalia. Russian Geology and Geophysics. 50, 603-609.

Munoz, M., Premo, W., Courjault-Rade, P., 2005. Sm–Nd dating of fluorite from the

worldclass Montroc fluorite deposit, southern Massif Central, France. Mineralium

Deposita. 39, 970-975.

Ni, P., Wang, G.-G., Cai, Y.-T., Zhu, X.-T., Yuan, H.-X., Huang, B., Ding, J.-Y. and

Chen, H. 2017, Genesis of the Late Jurassic Shizitou Mo deposit, South China:

Evidences from fluid inclusion, HO isotope and ReOs geochronology. Ore

Geology Reviews. 81, Part 2, 871-883.

121

Nie, F., Xu, D., Jiang, S. and Liu, Y. 2008, Geological features and origin of Sumoqagan

Obo superlarge independent fluorite deposit, Inner Mongolia. Mineral Deposits.

27, 1-13 (In Chinese with English abstract).

O'Neil, J.R., Clayton, R.N., Mayeda, T.K., 1969. Oxygen Isotope Fractionation in

Divalent Metal Carbonates. The Journal of Chemical Physics. 51, 5547-5558.

Ouyang, H.-g., Mao, J.-w., Santosh, M., Zhou, J., Zhou, Z.-h., Wu, Y., Hou, L., 2013.

Geodynamic setting of Mesozoic magmatism in NE China and surrounding

regions. Perspectives from spatio-temporal distribution patterns of ore deposits.

Journal of Asian Earth Sciences. 78, 222-236.

Ouyang, H., Mao, J., Zhou, Z., Su, H., 2015. Late Mesozoic metallogeny and

intracontinental magmatism, southern Great Xing'an Range, northeastern China.

Gondwana Research. 27, 1153-1172.

Partey, F., Lev, S., Casey, R., Widom, E., Lueth, V., Rakovan, J., 2005. Source of

fluorine and petrogenesis of the Rio Grande Rift type barite-fluorite-galena

deposits. Economic Geology. 69, A878.

Pearce, J.A., 1996. Sources and Settings of Granitic Rocks. Episodes. 19, 120-125.

Peccerillo, A., Taylor, S.R., 1976, Geochemistry of Eocene calc-alkaline volcanic rocks

from the Kastamonu area, northern Turkey. Contributions to Mineralogy and

Petrology. 58, 63-81.

Pei Q, Zhang S, Cao H, Wang L, Han S, Wu Z, Xia B. 2016. Feartures and potential

analysis of Xiaobeigou fluorite deposit in Linxi, Inner Mongolia. Journal of Guilin

University of Technology. 36, 426-34 (in Chinese with English abstract).

122

Pei, Q., Zhang, S., Santosh, M., Cao, H., Zhang, W., Hu, X., Wang, L., 2017.

Geochronology, geochemistry, fluid inclusion and C, O and Hf isotope

compositions of the Shuitou fluorite deposit, Inner Mongolia, China. Ore Geology

Reviews. 83, 174-190.

Pei, Q.-M., Zhang, S.-T., Hayashi, K.-i., Cao, H.-W., Li, D., Tang, L., Hu, X.-K., Li,

H.-X. and Fang, D.-R. 2018. Permo–Triassic granitoids of the Xing’an–Mongolia

segment of the Central Asian Orogenic Belt, Northeast China: age, composition,

and tectonic implications. International Geology Review. 60, 1172-1194.

Peng, J.T., Hu, R.Z., Burnard, P.G., 2003. Samarium–neodymium isotope systematics

of hydrothermal calcites from the Xikuangshan antimony deposit (Hunan, China):

the potential of calcite as a geochronometer. Chemical Geology. 200, 129-136.

Pirajno F, Ernst RE, Borisenko AS, Fedoseev G, Naumov EA. 2009. Intraplate

magmatism in Central Asia and China and associated metallogeny. Ore Geology

Reviews. 35, 114-36.

Piqué, À., Canals, À., Grandia, F. and Banks, D.A. 2008. Mesozoic fluorite veins in NE

Spain record regional base metal-rich brine circulation through basin and

basement during extensional events. Chemical Geology. 257, 139-152.

Rapp, R.P., Watson, E.B., 1995. Dehydration melting of metabasalt at 8–32 kbar.

implications for continental growth and crust-mantle recycling. Journal of

Petrology. 36, 891-931.

Ren, J., Tamaki, K., Li, S., Zhang, J., 2002. Late Mesozoic and Cenozoic rifting and its

dynamic setting in Eastern China and adjacent areas. Tectonophysics. 344 (3),

123

175–205.

Ren, J.S., Jiang, C.F., Zhang, Z.K., Qin, D.Y., 1980. The Geotectonic Evolution of

China. Science Press, Beijing (in Chinese).

Richardson, C.K., Holland, H.D., 1979a. Fluorite deposition in hydrothermal systems.

Geochimica et Cosmochimica Acta. 43, 1327-1335.

Richardson, C.K., Holland, H.D., 1979b. The solubility of fluorite in hydrothermal

solutions, an experimental study. Geochimica et Cosmochimica Acta. 43, 1313-

1325.

Richardson, C.K., Pinckney, D.M., 1984. The chemical and thermal evolution of the

fluids in the Cave-in-Rock fluorspar district, Illinois; mineralogy, paragenesis, and

fluid inclusions. Economic Geology. 79, 1833-1856.

Ripp G.S., Izbrodin I.A., Doroshkevich A.G., Rampilov M.O., Lastochkin E.I.,

Posokhov V.F. 2016. Carbonates and sources of fluids in ores and metasomatites

of the Ermakovka fluorite-bertrandite-phenacite deposit (western Transbaikalia).

Russian Geology and Geophysics. 57, 1288-1297.

Robb, L., 2005. Introduction to ore-forming processes. Blackwell Publishing.

Rossetti, P., Colombo, F., 1999. Adularia-sericite gold deposits of Marmato (Caldas,

Colombia): field and petrographical data. Geological Society, London, Special

Publications. 155, 167-182.

Ruan, B., Lv, X., Yang, W., Liu, S., Yu, Y., Wu, C. and Adam, M.M.A. 2015. Geology,

geochemistry and fluid inclusions of the Bianjiadayuan Pb–Zn–Ag deposit, Inner

Mongolia, NE China: Implications for tectonic setting and metallogeny. Ore

124

Geology Reviews. 71, 121-137.

Rubatto, D., Gebauer, D., 2000. Use of Cathodoluminescence for U-Pb Zircon Dating

by Ion Microprobe. Some Examples from the Western Alps, In. Pagel, M., Barbin.,

Blanc, P., Ohnenstetter, D. (Eds.), Cathodoluminescence in Geosciences. Springer

Berlin Heidelberg, Berlin, Heidelberg, pp. 373-400.

Rubinstein, N.A., Zappettini, E.O., 2015. Origin and age of rift related fluorite and

manganese deposits from the San Rafael Massif, Argentina. Ore Geology Reviews.

66, 334-343.

Ruiz, J., Jones, L.M., Kelly, W.C., 1984. Rubidium-strontium dating of ore deposits

hosted by Rb-rich rocks, using calcite and other common Sr-bearing minerals.

Geology. 12, 259-262.

Ruiz, J., Richardson, C.K., Patchett, P.J., 1988. Strontium isotope geochemistry of

fluorite, calcite, and barite of the Cave-in-Rock fluorite district, Illinois. Economic

Geology. 83, 203-210.

Safonova, I.Y., Santosh, M., 2014. Accretionary complexes in the Asia-Pacific region.

Tracing archives of ocean plate stratigraphy and tracking mantle plumes.

Gondwana Research. 25, 126-158.

Schwinn, G. and Markl, G. 2005. REE systematics in hydrothermal fluorite. Chemical

Geology. 216, 225-248.

Sengör, A.M.C. and Natal'in, B.A. 1996. Paleotectonics of Asia: Fragments of a

synthesis. Cambridge University Press, Cambridge, pp. 486–640.

Şengör, A.M.C., Natal'in, B.A., Burtman.S., 1993. Evolution of the Altaid tectonic

125

collage and Palaeozoic crustal growth in Eurasia. Nature. 364, 299-307.

Shao, J.A., Zhang, L., Xiao, Q., Li, X., 2005. Rising of Da Hinggan Mts in Mesozoic:

A Possible Mechanism of Intracontinental Orogeny. Acta Petrologica Sinica. 21,

789-794 (in Chinese with English abstract).

Shi, G., Liu, D., Zhang, F., Jian, P., Miao, L., Shi, Y., Tao, H., 2003. SHRIMP U-Pb

zircon geochronology and its implications on the Xilin Gol Complex, Inner

Mongolia, China. Chinese Science Bulletin. 48, 2742-2748.

Shi, G., Miao, L., Zhang, F., Jian, P., Fan, W., Liu, D., 2004. Emplacement age and

tectonic implications of the Xilinhot A-type granite in Inner Mongolia, China.

Chinese Science Bulletin. 49, 723-729.

Shi, G.R., 2006. The marine Permian of East and Northeast Asia. an overview of

biostratigraphy, palaeobiogeography and palaeogeographical implications.

Journal of Asian Earth Sciences. 26, 175-206.

Shi, Y.R., Liu, C., Deng, J.F., Jian, P., 2014. Geochronological frame of granitoids from

Central Inner Mongolia and its tectonomagmatic evolution. Acta Petrologica

Sinica. 30, 3155-3171. (in Chinese with English abstract)

Shu, Q., Lai, Y., Sun, Y., Wang, C., Meng, S., 2013. Ore genesis and hydrothermal

evolution of the Baiyinnuo’er zinc-lead skarn deposit, Northeast China: evidence

from isotopes (S, Pb) and fluid inclusions. Economic Geology. 108, 835-860.

Shu, Q., Lai, Y., Wang, C., Xu, J., Sun, Y., 2014. Geochronology, geochemistry and Sr–

Nd–Hf isotopes of the Haisugou porphyry Mo deposit, northeast China, and their

geological significance. Journal of Asian Earth Sciences. 79, Part B, 777-791.

126

Shu, Q., Lai, Y., Wei, L., Sun, Y., Wang, C., 2011. Fluid Inclusion Study of the

Baiyinnuo'er Zn-Pb Deposit, South Segment of the Great Xing'an Mountain,

Northeaster China. Acta Petrologica Sinica. 27, 1467-1482 (in Chinese with

English abstract).

Sibson, R.H., 1987. Earthquake rupturing as a mineralizing agent in hydrothermal

systems. Geology. 15, 701-704.

Simmons, S.F., Browne, P.R.L., 1998. Lattice textures in vein deposits and geothermal

systems in New Zealand: Clues to understanding boiling processes in epithermal

environments, 14th Australian Geological Convention. Geological Society of

Australia, Abstracts, 406.

Simmons, S.F., Christenson, B.W., 1994. Origins of calcite in a boiling geothermal

system. American Journal of Science. 294, 361-400.

Simmons, S.F., White, N.C., John, D.A., 2005. Geological characteristics of epithermal

precious and base metal deposits. Economic Geology. 100th anniversary volume

29, 485-522.

Smithies, R.H., Champion, D.C., 2000, The Archaean High-Mg Diorite Suite. Links to

Tonalite–Trondhjemite–Granodiorite Magmatism and Implications for Early

Archaean Crustal Growth. Journal of Petrology. 41, 1653-1671.

Smolyanskii, P.L., Bogomolov, E.S., 2011. Structural-morphological and REE

geochemical control of the correctness of Sm–Nd dating for fluorite formation in

the garsonui deposit, eastern Transbaikalia. Petrology. 19, 297-302.

Sobolev, S.V., Sobolev, A.V., Kuzmin, D.V., Krivolutskaya, N.A., Petrunin, A.G., Arndt,

127

N.T., Radko, V.A., Vasiliev, Y.R., 2011. Linking mantle plumes, large igneous

provinces and environmental catastrophes. Nature. 477 (7364), 312–316.

Söderlund, U., Patchett, P.J., Vervoort, J.D., Isachsen, C.E., 2004, The 176Lu decay

constant determined by Lu–Hf and U–Pb isotope systematics of Precambrian

mafic intrusions. Earth and Planetary Science Letters. 219, 311-324.

Song, S., Wang, M.-M., Xu, X., Wang, C., Niu, Y., Allen, M.B., Su, L., 2015, Ophiolites

in the Xing'an-Inner Mongolia accretionary belt of the CAOB. Implications for

two cycles of seafloor spreading and accretionary orogenic events. Tectonics. 34,

2221-2248.

Souissi, F., Jemmali, N., Souissi, R. and Dandurand, J.L. 2013. REE and isotope (Sr, S,

and Pb) geochemistry to constrain the genesis and timing of the F–(Ba–Pb–Zn)

ores of the Zaghouan District (NE Tunisia). Ore Geology Reviews. 55, 1-12.

Spirakis, C.S., Heyl, A.V., 1995. Evaluation of proposed precipitation mechanisms for

Mississippi Valley-type deposits. Ore Geology Reviews. 10, 1-17.

Sun, S.S., and McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic

basalts, implications for mantle composition and processes, in Saunders, A.D., and

Norry, M.J., eds., Magmatism in Ocean basins. London, Geological Society

Special Publication, 42, 313-345.

Sun, X., 2007. Prediction of fluorite deposit in Yixian based on fuzzy-neural network.

Journal of China University of Geosciences. 18, 279-281.

Tang J, Xu W-L, Wang F, Zhao S, Wang W. 2016. Early Mesozoic southward

subduction history of the Mongol–Okhotsk oceanic plate: Evidence from

128

geochronology and geochemistry of Early Mesozoic intrusive rocks in the Erguna

Massif, NE China. Gondwana Research. 31, 218-40.

Taylor, H.P. 1974. The Application of Oxygen and Hydrogen Isotope Studies to

Problems of Hydrothermal Alteration and Ore Deposition. Economic Geology. 69,

843-883.

Taylor, H.P. 1997. Oxygen and hydrogen isotope relationships in hydrothermal mineral

deposits. Wileym New York, In: Barnes, H.L. (Ed.), pp. 229-302.

Tong, Y., Jahn, B.-m., Wang, T., Hong, D.-w., Smith, E.I., Sun, M., Gao, J.-f., Yang, Q.-

d., Huang, W., 2015. Permian alkaline granites in the Erenhot–Hegenshan belt,

northern Inner Mongolia, China. Model of generation, time of emplacement and

regional tectonic significance. Journal of Asian Earth Sciences. 97, Part B, 320-

336.

Tu, G. 1996. Geochemistry of Stratabound Deposits in China. Science Press, Beijing,

pp. 1-639.

Veksler, I.V., Dorfman, A.M., Kamenetsky, M., Dulski, P., Dingwell, D.B., 2005.

Partitioning of lanthanides and Y between immiscible silicate and fluoride melts,

fluorite and cryolite and the origin of the lanthanide tetrad effect in igneous rocks.

Geochimica et Cosmochimica Acta. 69, 2847-2860.

Vervoort, J.D., Jonathan Patchett, P., 1996, Behavior of hafnium and neodymium

isotopes in the crust. Constraints from Precambrian crustally derived granites.

Geochimica et Cosmochimica Acta. 60, 3717-3733.

Wang, C., Bagas, L., Lu, Y., Santosh, M., Du, B., McCuaig, T.C., 2016a, Terrane

129

boundary and spatio-temporal distribution of ore deposits in the Sanjiang Tethyan

Orogen. Insights from zircon Hf-isotopic mapping. Earth-Science Reviews. 156,

39-65.

Wang, C., Chen, L., Bagas, L., Lu, Y., He, X., Lai, X., 2016b, Characterization and

origin of the Taishanmiao aluminous A-type granites. implications for Early

Cretaceous lithospheric thinning at the southern margin of the North China Craton.

International Journal of Earth Sciences. 105, 1563-1589.

Wang, C., Deng, J., Lu, Y., Bagas, L., Kemp, A.I.S., McCuaig, T.C., 2015a, Age, nature,

and origin of Ordovician Zhibenshan granite from the Baoshan terrane in the

Sanjiang region and its significance for understanding Proto-Tethys evolution.

International Geology Review. 57, 1922-1939.

Wang, C., Deng, J., Santosh, M., Lu, Y., McCuaig, T.C., Carranza, E.J.M., Wang, Q.,

2015b, Age and origin of the Bulangshan and Mengsong granitoids and their

significance for post-collisional tectonics in the Changning–Menglian Paleo-

Tethys Orogen. Journal of Asian Earth Sciences. 113, 656-676.

Wang C, Zhang DA, Wu G, Xu Y, Carranza EJM, Zhang Y, Li H, Geng J. 2013. Zircon

U–Pb geochronology and geochemistry of rhyolitic tuff, granite porphyry and

syenogranite in the Lengshuikeng ore district, SE China: Implications for a

continental arc to intra-arc rift setting. Journal of Earth System Science. 122, 809-

30.

Wang, D.-H., Tang, J.-X., Ying, L.-J., Chen, Z.-H., Xu, J.-x., Zhang, J.-J., Li, S.-R. and

Zheng, Z.-L. 2010. Application of "Five levels+Basement" model for prospecting

130

deposits into depth. J. Jilin Univ. (Earth Sci. Ed.), 40, 733-738 (In Chinese with

English abstract).

Wang, G., Wu, C., Chen, C., Zhou, Z., Liu, C., Jiang, T., 2017. Geochronological data

of igneous and metamorphic rocks from the Xing’an-Mongolia Orogenic Belt of

the eastern Central Asian Orogenic Belt. implications for the final closure of the

Paleo-Asian Ocean. International Journal of Earth Sciences. doi. 10.1007/s00531-

017-1456-y

Wang, J., Shang, p., Xiong, X., Yang, H., Tang, R., 2015c. Metallogenic Regularities of

Fluorite Deposits in China. Geology in China. 42, 18-32 (in Chinese with English

abstract).

Wang, L.J., Shimazaki, H., Shiga, Y., 2001. Skarns and genesis of the Huanggang Fe-

Sn deposit, Inner Mongolia, China. Resource Geology. 51, 359-376.

Wang, L.J., Wang, Y.W., Wang, J.B., Gunther, D., 2006. Fluid mineralization of the

Dajing Sn-polymetal deposit: Evidence from LA-ICP-MS analysis of individual

fluid inclusions. Chinese Science Bulletin. 51, 2781-2788.

Wang, Q., Liu, X., 1986. Paleoplate tectonics between Cathaysia and Angaraland in

inner Mongolia of China. Tectonics. 5, 1073-1088.

Wang, T., Guo, L., Zhang, L., Yang, Q., Zhang, J., Tong, Y., Ye, K., 2015d. Timing and

evolution of Jurassic–Cretaceous granitoid magmatisms in the Mongol–Okhotsk

belt and adjacent areas, NE Asia: Implications for transition from contractional

crustal thickening to extensional thinning and geodynamic settings. Journal of

Asian Earth Sciences. 97, Part B, 365-392.

131

Wang, Z.W., Pei, F.P, Xu, W.L., Cao, H.H., Wang, Z.J., Zhang, Y., 2016c. Tectonic

evolution of the eastern Central Asian Orogenic Belt: Evidence from zircon U–

Pb–Hf isotopes and geochemistry of early Paleozoic rocks in Yanbian region, NE

China. Gondwana Research. 38, 334-350.

Whalen, J., Currie, K., Chappell, B., 1987. A-type granites. geochemical characteristics,

discrimination and petrogenesis. Contributions to Mineralogy and Petrology. 95,

407-419.

Wiedenbeck, M., AllÉ, P., Corfu, F., Griffin, W.L., Meier, M., Oberli, F., Quadt, A.V.,

Roddick, J.C., Spiegel, W., 1995. Three natural zircon standards for U-Th-Pb, Lu–

Hf, trace element and ree analyses. Geostandards Newsletter. 19, 1-23.

Wilde, S.A., 2015, Final amalgamation of the Central Asian Orogenic Belt in NE China:

Paleo-Asian Ocean closure versus Paleo-Pacific plate subduction - A review of the

evidence: Tectonophysics. 662, 345-362.

Wilkinson, J.J., 2001. Fluid inclusions in hydrothermal ore deposits. Lithos. 55, 229-

272.

Windley, B.F., Alexeiev, D., Xiao, W.J., Kroner, A., Badarch, G., 2007, Tectonic models

for accretion of the Central Asian Orogenic Belt. Journal of the Geological Society.

164, 31-47.

Wu, C., Jiang, T., Liu, C., Liu, W., 2014, Early Cretaceous A-type granites and Mo

mineralization, Aershan area, eastern Inner Mongolia, Northeast China.

geochemical and isotopic constraints. International Geology Review. 56, 1357-

1376.

132

Wu, C., Wang, B., Zhou, Z., Wang, G., Zuza, A.V., Liu, C., Jiang, T., Liu, W., Ma, S.,

2017, The relationship between magma and mineralization in Chaobuleng iron

polymetallic deposit, Inner Mongolia. Gondwana Research. 45, 228-253.

Wu, F.-Y., Jahn, B.-M., Wilde, S.A., Lo, C.-H., Yui, T.-F., Lin, Q., Ge, W.-c., Sun, D.-

y., 2003, Highly fractionated I-type granites in NE China (I). geochronology and

petrogenesis. Lithos. 66, 241-273.

Wu, F.-Y., Sun, D.-Y., Ge, W.-C., Zhang, Y.-B., Grant, M.L., Wilde, S.A., Jahn, B.-M.,

2011a, Geochronology of the Phanerozoic granitoids in northeastern China.

Journal of Asian Earth Sciences. 41, 1-30.

Wu, F.-Y., Sun, D.-Y., Li, H., Jahn, B.-m., Wilde, S., 2002. A-type granites in

northeastern China: age and geochemical constraints on their petrogenesis.

Chemical Geology. 187, 143-173.

Wu, F.-Y., Yang, Y.-H., Xie, L.-W., Yang, J.-H., Xu, P., 2006. Hf isotopic compositions

of the standard zircons and baddeleyites used in U–Pb geochronology. Chemical

Geology. 234, 105-126.

Wu, F.-Y., Zhao, G.-C., Sun, D.-Y., Wilde, S.A., Yang, J.-H., 2007. The Hulan Group.

Its role in the evolution of the Central Asian Orogenic Belt of NE China. Journal

of Asian Earth Sciences. 30, 542-556.

Wu, H., Zhang, L., Wan, B., Chen, Z., Xiang, P., Pirajno, F., Du, A. and Qu, W. 2011b,

Re–Os and 40Ar/39Ar ages of the Jiguanshan porphyry Mo deposit, Xilamulun

metallogenic belt, NE China, and constraints on mineralization events.

Mineralium Deposita. 46, 171-185.

133

Xiao, W., Kröner, A., Windley, B., 2009. Geodynamic evolution of Central Asia in the

Paleozoic and Mesozoic. International Journal of Earth Sciences. 98, 1185-1188.

Xiao, W., Li, S., Santosh, M., Jahn, B.-m., 2012. Orogenic belts in Central Asia.

Correlations and connections. Journal of Asian Earth Sciences. 49, 1-6.

Xiao, W., Sun, M., Santosh, M., 2015a. Continental reconstruction and metallogeny of

the Circum-Junggar areas and termination of the southern Central Asian Orogenic

Belt. Geoscience Frontiers. 6, 137-140.

Xiao, W., Windley, B.F., Hao, J., Zhai, M., 2003. Accretion leading to collision and the

Permian Solonker suture, Inner Mongolia, China. Termination of the central Asian

orogenic belt. Tectonics. 22, 1/8-20/20.

Xiao, W., Windley, B.F., Sun, S., Li, J., Huang, B., Han, C., Yuan, C., Sun, M., Chen,

H., 2015b. A Tale of Amalgamation of Three Permo-Triassic Collage Systems in

Central Asia. Oroclines, Sutures, and Terminal Accretion. Annual Review of Earth

and Planetary Sciences. 43, 477-507.

Xu, B., Charvet, J., Chen, Y., Zhao, P., Shi, G., 2013a. Middle Paleozoic convergent

orogenic belts in western Inner Mongolia (China): framework, kinematics,

geochronology and implications for tectonic evolution of the Central Asian

Orogenic Belt. Gondwana Research. 23, 1342-1364.

Xu, B., Song, S., Nie, F., 2015a. The Central Asian Orogenic Belt in northern China.

Preface. Journal of Asian Earth Sciences. 97, Part B, 179-182.

Xu, B., Zhao, P., Wang, Y., Liao, W., Luo, Z., Bao, Q., Zhou, Y., 2015b. The pre-

Devonian tectonic framework of Xing’an–Mongolia orogenic belt (XMOB) in

134

north China. Journal of Asian Earth Sciences. 97, Part B, 183-196.

Xu, C., Taylor, R.N., Li, W., Kynicky, J., Chakhmouradian, A.R., Song, W., 2012.

Comparison of fluorite geochemistry from REE deposits in the Panxi region and

Bayan Obo, China. Journal of Asian Earth Sciences. 57, 76-89.

Xu, D., 2009. Geological Setting, Features and Origin of the Sumochagan Obo Super-

large Fluorite Mineralized District, In: Xu, D. (Ph.D. thesis). Chinese Academy of

Geological Sciences Beijing, pp. 1-145.

Xu, D., Nie, F., Jiang, S., Zhang, W., Yun, F., Yang, C., Zhang, T., Lv, X. and Lin, R.

2008. Geological and geochemical characteristics of the Aobaotu fluorite deposit

in Inner Mongolia. Acta Geoscientica Sinica. 29, 440-450 (In Chinese with

English abstract).

Xu W, Fan H, Hu F, Santosh M, Yang K, Lan T, Wen B. 2015c. Geochronology of the

Guilaizhuang gold deposit, Luxi Block, eastern North China Craton: Constraints

from zircon U–Pb and fluorite-calcite Sm–Nd dating. Ore Geology Reviews. 65,

390-9.

Xu, W.-L., Pei, F.-P., Wang, F., Meng, E., Ji, W.-Q., Yang, D.-B., Wang, W., 2013b.

Spatial–temporal relationships of Mesozoic volcanic rocks in NE China:

Constraints on tectonic overprinting and transformations between multiple

tectonic regimes. Journal of Asian Earth Sciences. 74, 167-193.

Xu, Z., Wu, Z., Zhang, S. and Yang, G. 1991. Metallogenic regularity and metallogenic

prognosis of the fluorite deposits in Zhejiang Province. Sichuan Science and

Technology Press, Chengdu, pp. 1-190 (In Chinese).

135

Xu, Z. and Zhang, S. 2013c. Spatiotemporal evolution of fluorite deposits and detailed

investigation on the typical fluorite district in Zhejiang Province. Geological

Publishing House, Beijing, pp. 1-240 (In Chinese).

Yakubchuk, A., 2004. Architecture and mineral deposit settings of the Altaid orogenic

collage. a revised model. Journal of Asian Earth Sciences. 23, 761-779.

Yang, H., Ge, W.-c., Yu, Q., Ji, Z., Liu, X.-w., Zhang, Y.-l., Tian, D.-x., 2016a. Zircon

U-Pb-Hf isotopes, bulk-rock geochemistry and petrogenesis of Middle to Late

Triassic I-type granitoids in the Xing’an Block, northeast China. Implications for

early Mesozoic tectonic evolution of the central Great Xing’an Range. Journal of

Asian Earth Sciences. 119, 30-48.

Yang, H., Ge, W., Zhao, G., Yu, J., Zhang, Y., 2014a. Early Permian–Late Triassic

granitic magmatism in the Jiamusi–Khanka Massif, eastern segment of the Central

Asian Orogenic Belt and its implications. Gondwana Research. doi.

http.//dx.doi.org/10.1016/j.gr.2014.01.011

Yang, J.-H., Wu, F.-Y., Shao, J.-A., Wilde, S.A., Xie, L.-W., Liu, X.-M., 2006.

Constraints on the timing of uplift of the Yanshan Fold and Thrust Belt, North

China. Earth and Planetary Science Letters. 246, 336-352.

Yang, Q., Guo, L., wang, T., Zeng, T., Zhang, L., Tong, Y., Shi, X., Zhang, J., 2014b.

Geochronology, Origin, sources and tectonic settings of Late Mesozoic two-stage

granites in the Ganzhuermiao region, central and southern Da Hinggan Range, NE

China. Acta Petrologica Sinica. 30, 1961-1981 (in Chinese with English abstract).

Yang, Q., Wang, T., Guo, L., Tong, Y., Zhang, L., Zhang, J., Hou, Z., 2017. Nd isotopic

136

variation of Paleozoic–Mesozoic granitoids from the Da Hinggan Mountains and

adjacent areas, NE Asia. Implications for the architecture and growth of

continental crust. Lithos. 272–273, 164-184.

Yang, Q.Y., Santosh, M., Collins, A.S., Teng, X.M., 2016b. Microblock amalgamation

in the North China Craton: Evidence from Neoarchaean magmatic suite in the

western margin of the Jiaoliao Block. Gondwana Research. 31, 96-123.

Yang, X.-Y., Sun, W.-D., Zhang, Y.-X. and Zheng, Y.-F. 2009, Geochemical constraints

on the genesis of the Bayan Obo Fe–Nb–REE deposit in Inner Mongolia, China.

Geochimica et Cosmochimica Acta. 73, 1417-1435.

Yang, Y.T., Guo, Z.X., Song, C.C., Li, X.B., He, S., 2015. A short-lived but significant

Mongol–Okhotsk collisional orogeny in latest Jurassic–earliest Cretaceous.

Gondwana Research. 28, 1096-1116.

Ying, J.F., Zhou, X.H., Zhang, L.C., Wang, F., 2010. Geochronological framework of

Mesozoic volcanic rocks in the Great Xing’an Range, NE China, and their

geodynamic implications. Journal of Asian Earth Sciences 39, 786–793.

Zappettini, E.O., Rubinstein, N., Crosta, S. and Segal, S.J. 2017. Intracontinental rift-

related deposits: A review of key models. Ore Geology Reviews. 89, 594-608.

Zeng, Q., Liu, J., Yu, C., Ye, J., Liu, H., 2011. Metal deposits in the Da Hinggan

Mountains, NE China: styles, characteristics, and exploration potential.

International Geology Review. 53, 846-878.

Zeng, Q.-D., Sun, Y., Chu, S.-X., Duan, X.-X., Liu, J., 2015. Geochemistry and

geochronology of the Dongshanwan porphyry Mo–W deposit, Northeast China:

137

Implications for the Late Jurassic tectonic setting. Journal of Asian Earth Sciences.

97, 472-485.

Zeng, Z., Cao, H., Gao, F., Gao, Y., Zou, H. and Li, D. 2013, Fluid inclusion study of

fluorite deposits in Linxi region, Inner Mongolia. Geochimica, 42, 73-81 (In

Chinese with English abstract).

Zhai, D., Liu, J., Wang, J., Yang, Y., Zhang, H., Wang, X., Zhang, Q., Wang, G., Liu,

Z., 2014a, Zircon U–Pb and molybdenite Re–Os geochronology, and whole-rock

geochemistry of the Hashitu molybdenum deposit and host granitoids, Inner

Mongolia, NE China: Journal of Asian Earth Sciences. 79, 144-160.

Zhai, D., Liu, J., Zhang, H., Yao, M., Wang, J., Yang, Y., 2014b. S–Pb isotopic

geochemistry, U–Pb and Re–Os geochronology of the Huanggangliang Fe–Sn

deposit, Inner Mongolia, NE China. Ore Geology Reviews. 59, 109-122.

Zhang, C., Wu, Y., Hou, L., Mao, J., 2015a. Geodynamic setting of mineralization of

Mississippi Valley-type deposits in world-class Sichuan–Yunnan–Guizhou Zn–Pb

triangle, southwest China: Implications from age-dating studies in the past decade

and the Sm–Nd age of Jinshachang deposit. Journal of Asian Earth Sciences. 103,

103-114.

Zhang, F.F., Wang, Y.H., Liu, J.J., 2016a. Petrogenesis of Late Carboniferous granitoids

in the Chihu area of Eastern Tianshan, Northwest China, and tectonic implications.

geochronological, geochemical, and zircon Hf-O isotopic constraints.

International Geology Review. 58, 949-966.

Zhang, F.Q., Chen, H.L., Yu, X., Dong, C.W., Yang, S.F., Pang, Y.M., Batt, G.E., 2011.

138

Early Cretaceous volcanism in the northern Songliao Basin, NE China, and its

geodynamic implication. Gondwana Research. 19, 163-176.

Zhang, H., Cao, J., Xie, X., 1996. Raman and Luminescence Spectral Studies of Natural

Fluorite. Acta Mineralogica Sinica. 16, 394-402 (in Chinese with English abstract).

Zhang, J., Bian, X., Chen, S., Zheng, Y., Tang, Y., Jiang, X., Cong, F. and Huang, X.

2013. Shale gas resources prospect of late Permain Linxi Formation in the middle-

southern part of the Da Hinggan Mountains. Geol. Bull. China, 32, 1297-1306 (In

Chinese with English abstract).

Zhang, J.-H., Gao, S., Ge, W.-C., Wu, F.-Y., Yang, J.-H., Wilde, S.A. and Li, M. 2010a.

Geochronology of the Mesozoic volcanic rocks in the Great Xing'an Range,

northeastern China: Implications for subduction-induced delamination. Chem.

Geol., 276, 144-165.

Zhang, J., Wei, C., Chu, H., Chen, Y., 2016b. Mesozoic metamorphism and its tectonic

implication along the Solonker suture zone in central Inner Mongolia, China.

Lithos. v. 261, 262-277.

Zhang, J., Wei, C., Chu, H., 2015b. Blueschist metamorphism and its tectonic

implication of Late Paleozoic–Early Mesozoic metabasites in the mélange zones,

central Inner Mongolia, China. Journal of Asian Earth Sciences. 97, Part B, 352-

364.

Zhang, L.G. 1985. The Application of the Stable Isotope to Geology. Shanxi Science

and Technology Press, Xi’an, pp. 1–91. (In Chinese).

Zhang, L., Wu, H., Xiang, P., Zhang, X., Chen, Z., Wan, B., 2010b. Ore-forming

139

Processes and Mineralization of Complex Tectonic System During the Mesozoic:

A Case from Xilamulun Cu-Mo Metallogenic Belt. Acta Petrologica Sinica. 26,

1351-1362 (in Chinese with English abstract).

Zhang, Q., Jin, W., Li, C., Wang, Y., 2009b. Yanshanian Large-scale Magmatism and

Lithosphere Thining in Eastern China: Relation to Large Igneous Province. Earth

Science Frontiers (China University of Geosciences(Beijing); Peking University),

21-51 (in Chinese with English abstract).

Zhang, Q., Wang, C.Y., Liu, D., Jian, P., Qian, Q., Zhou, G., Robinson, P.T., 2008a. A

brief review of ophiolites in China. Journal of Asian Earth Sciences. 32, 308-324.

Zhang, S., Cao, H., Zheng, L., Ma, Y., Fang, Y., Zou, H., 2014a. Characteristics of Ore-

forming Fluids and Mineralization Processes of the Shuitou Fluorite Deposit in

Linxi, Inner Mongolia Autonomous Region. Earth Science Frontiers (China

University of Geosciences(Beijing); Peking University) 21, 31-40 (in Chinese

with English abstract).

Zhang, S.-H., Zhao, Y., Song, B., Hu, J.-M., Liu, S.-W., Yang, Y.-H., Chen, F.-K., Liu,

X.-M., Liu, J., 2009a. Contrasting Late Carboniferous and Late Permian–Middle

Triassic intrusive suites from the northern margin of the North China craton.

Geochronology, petrogenesis, and tectonic implications. Geological Society of

America Bulletin. 121, 181-200.

Zhang, S., Gao, R., Li, H., Hou, H., Wu, H., Li, Q., Yang, K., Li, C., Li, W., Zhang, J.,

Yang, T., Keller, G.R., Liu, M., 2014b. Crustal structures revealed from a deep

seismic reflection profile across the Solonker suture zone of the Central Asian

140

Orogenic Belt, northern China. An integrated interpretation. Tectonophysics. 612-

613, 26-39.

Zhang, W., 2014. Vertical Zoning Characteristics and Prediction of Fluorite Deposits in

Linxi Region, Inner Mongolia (Master thesis). China University of Geosciences,

Beijing, pp. 1-75 (in Chinese with English abstract).

Zhang, X., Gu, J., Luo, P., Zhu, R., Luo, Z., 2006. Geneis of the Fluorite in the

Ordovician and Its Significance to the Petroleum Geology of Tarim Basin. Acta

Petrologica Sinica. 22, 2220-2228 (in Chinese with English abstract).

Zhang, X., Wang, K., Fu, L., Zhang, M., Konare, Y., Peng, D. and Cai, W. 2017a. Fluid

inclusions, C-H-O-S isotope and geochronology of the Bujinhei Pb-Zn deposit in

the Southern Great Xing'an Range of Northeast China: Implication for ore genesis.

Resour. Geol., 67, 207-227.

Zhang, X., Yuan, L., Xue, F., Yan, X., Mao, Q., 2015c. Early Permian A-type granites

from central Inner Mongolia, North China. Magmatic tracer of post-collisional

tectonics and oceanic crustal recycling. Gondwana Research. 28, 311-327.

Zhang, X.H., Zhang, H.F., Tang, Y.J., Wilde, S.A., Hu, Z.C., 2008b. Geochemistry of

Permian bimodal volcanic rocks from central inner Mongolia, North China:

Implication for tectonic setting and Phanerozoic continental growth in Central

Asian Orogenic Belt. Chemical Geology. 249, 262-281.

Zhang, Y.-M., Gu, X.-X., Liu, R.-P., Sun, X., Li, X.-L. and Zheng, L. 2017b. Geology,

geochronology and geochemistry of the Gaogangshan Mo deposit: A newly

discovered Permo-Triassic collision-type Mo mineralization in the Lesser Xing'an

141

Range, NE China. Ore Geol. Rev., 81, Part 2, 672-688.

Zhao, P., Faure, M., Chen, Y., Shi, G., Xu, B., 2015. A new Triassic shortening-extrusion

tectonic model for Central-Eastern Asia. Structural, geochronological and

paleomagnetic investigations in the Xilamulun Fault (North China). Earth and

Planetary Science Letters. 426, 46-57.

Zhao, P., Jahn, B.-m., Xu, B., Liao, W., Wang, Y., 2016. Geochemistry, geochronology

and zircon Hf isotopic study of peralkaline-alkaline intrusions along the northern

margin of the North China Craton and its tectonic implication for the southeastern

Central Asian Orogenic Belt. Lithos. 261, 92-108.

Zhao, P., Xu, B., Zhang, C., 2017. A rift system in southeastern Central Asian Orogenic

Belt. Constraint from sedimentological, geochronological and geochemical

investigations of the Late Carboniferous-Early Permian strata in northern Inner

Mongolia (China). Gondwana Research. 47, 342-357.

Zhong, S., Mucci, A., 1995. Partitioning of rare earth elements (REEs) between calcite

and seawater solutions at 25°C and 1 atm, and high dissolved REE concentrations.

Geochimica et Cosmochimica Acta. 59, 443-453.

Zhong, J., Chen, Y.-J., Qi, J.-P., Chen, J., Dai, M.-C. and Li, J. 2017. Geology, fluid

inclusion and stable isotope study of the Yueyang Ag-Au-Cu deposit, Zijinshan

orefield, Fujian Province, China. Ore Geology Reviews. 86, 254-270.

Zhou, J.-B., Han, J., Zhao, G.-C., Zhang, X.-Z., Cao, J.-L., Wang, B., Pei, S.-H., 2015a.

The emplacement time of the Hegenshan Ophiolite. Constraints from the

unconformably overlying Paleozoic strata. Tectonophysics. 662, 398-415.

142

Zhou, J.-B., Wilde, S.A., 2013. The crustal accretion history and tectonic evolution of

the NE China segment of the Central Asian Orogenic Belt: Gondwana Research.

23, 1365-1377.

Zhou, Z.-H., Mao, J.-W., Wu, X.-L., Ouyang, H.-G., 2015b. Geochronology and

geochemistry constraints of the Early Cretaceous Taibudai porphyry Cu deposit,

northeast China, and its tectonic significance. Journal of Asian Earth Sciences. 103,

212-228.

Zou, D., Liu, Y., Hu, Z., Gao, S., Zong, K., Xu, R., Deng, L., He, D., Gao, C., 2014,

Pyroxenite and peridotite xenoliths from Hexigten, Inner Mongolia. Insights into

the Paleo-Asian Ocean subduction-related melt/fluid–peridotite interaction.

Geochimica et Cosmochimica Acta. 140, 435-454.

Zou, H., Zhang, S.-t., Chen, A.-q., Fang, Y. and Zeng, Z.-f. 2016. Hydrothermal fluid

sources of the Fengjia barite–fluorite deposit in Southeast Sichuan, China:

Evidence from fluid Inclusions and hydrogen and oxygen isotopes. Resource

Geology. 66, 24-36.

Zhou, Z.-H., Mao, J.-W., Lyckberg, P., 2012. Geochronology and isotopic geochemistry

of the A-type granites from the Huanggang Sn–Fe deposit, southern Great Hinggan

Range, NE China: Implication for their origin and tectonic setting. Journal of

Asian Earth Sciences. 49, 272-286.

143

Appendix I: Analytical data

Table 1.1 Descriptions of the four representative granitoid plutons in the Linxi area

Modal mineral (vol%) Pluton Sample NO. Location Lithology Texture Qtz Kf Pl Bt Hbl accessory minerals

N43°53′08.13″ Xinangou XNG-6 monzogranite fine granitic texture 25 30-35 40 3 Zr+Ap+Mt E117°48′11.42″

N43°57′24.31″ Banshifangzi B-1-2 granodiorite fine granitic texture 30 15 45-50 3 2 Zr+Ap+Tn E117°46′32.78″

N43°55′19.90″ Banshifangzi B-2-1 granodiorite porphyry porphyritic texture 20-25 20 45-50 2-5 3-5 Zr+Tn+Mt E117°45′07.89″

N43°37′22.88″ Baoshan BS-3 monzogranite fine granitic texture 45-50 25-30 20 3 Zr+Fl+Ap E117°57′01.36″

N43°39′37.30″ Hada HD-3 biotite granite medium granitic texture 45-50 30 15 5-10 Fl+Zr+Ap+Mt E117°56′36.04″

Note: Ap = apatite; Bt = biotite; Fl = fluorite; Hbl = hornblende; Kf = potassium feldspar; Mt = magnetite; Pl = plagioclase; Qtz = quartz; Tn = titanite; and Zr = zircon.

144

Table 1.2 LA-ICP-MS Zircon U-Pb isotope data for the Linxi granitoids

Analysis Th U Corrected Isotopic ratios Age（Ma） Th/U spot (ppm) (ppm) 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ

BSFZ-G01

1 287.69 689.18 0.42 0.0525 0.0011 0.2853 0.0069 0.0400 0.0012 308 46 255 5 253 7

2 195.85 445.51 0.44 0.0534 0.0011 0.3013 0.0075 0.0403 0.0012 345 48 267 6 255 7

3 121.49 384.07 0.32 0.0522 0.0012 0.3037 0.0081 0.0427 0.0012 294 51 269 6 269 8

4 522.60 1257.56 0.42 0.0550 0.0011 0.2838 0.0066 0.0401 0.0012 412 44 254 5 253 7

5 309.20 786.80 0.39 0.0528 0.0011 0.2822 0.0068 0.0400 0.0012 320 46 252 5 253 7

6 481.82 1187.26 0.41 0.0558 0.0013 0.2827 0.0076 0.0401 0.0012 444 50 253 6 253 7

7 176.92 694.83 0.25 0.0528 0.0011 0.2852 0.0070 0.0395 0.0011 318 47 255 6 250 7

8 305.06 897.08 0.34 0.0530 0.0011 0.2824 0.0066 0.0400 0.0012 327 44 253 5 253 7

9 455.85 1257.71 0.36 0.0530 0.0011 0.2857 0.0069 0.0405 0.0012 330 46 255 5 256 7

10 690.27 1543.30 0.45 0.0544 0.0011 0.2774 0.0066 0.0391 0.0011 387 45 249 5 247 7

11 361.59 1333.14 0.27 0.0541 0.0014 0.2878 0.0084 0.0402 0.0012 374 55 257 7 254 7

12 523.43 2142.93 0.24 0.0536 0.0011 0.2717 0.0063 0.0392 0.0011 352 44 244 5 248 7

13 180.87 506.04 0.36 0.0515 0.0013 0.2901 0.0085 0.0406 0.0012 264 56 259 7 257 7

145

14 604.33 1304.54 0.46 0.0536 0.0011 0.2855 0.0066 0.0406 0.0012 355 44 255 5 256 7

15 290.10 947.43 0.31 0.0504 0.0011 0.2700 0.0070 0.0382 0.0011 213 51 243 6 242 7

16 747.74 1433.88 0.52 0.0548 0.0011 0.2811 0.0064 0.0397 0.0011 406 43 252 5 251 7

17 314.00 910.01 0.35 0.0526 0.0011 0.2775 0.0065 0.0392 0.0011 311 45 249 5 248 7

18 292.68 1011.60 0.29 0.0521 0.0011 0.2802 0.0067 0.0397 0.0011 291 46 251 5 251 7

19 240.89 617.76 0.39 0.0525 0.0011 0.2801 0.0069 0.0396 0.0011 305 47 251 5 251 7

20 299.32 1069.08 0.28 0.0539 0.0011 0.2851 0.0067 0.0401 0.0012 365 45 255 5 254 7

21 150.19 454.57 0.33 0.0521 0.0012 0.2733 0.0071 0.0389 0.0011 289 50 245 6 246 7

BSFZ-G02

1 119.89 304.66 0.39 0.0526 0.0012 0.2726 0.0073 0.0387 0.0011 312 52 245 6 245 7

2 98.43 282.97 0.35 0.0532 0.0013 0.2736 0.0078 0.0385 0.0011 339 54 246 6 243 7

3 109.21 354.69 0.31 0.0526 0.0012 0.2764 0.0075 0.0391 0.0011 311 52 248 6 247 7

4 113.02 298.93 0.38 0.0521 0.0012 0.2789 0.0075 0.0392 0.0011 291 52 250 6 248 7

5 57.87 211.49 0.27 0.0531 0.0013 0.2719 0.0075 0.0388 0.0011 334 53 244 6 246 7

6 105.81 306.70 0.34 0.0531 0.0015 0.2724 0.0089 0.0388 0.0011 334 63 245 7 245 7

7 103.37 260.45 0.40 0.0531 0.0013 0.2787 0.0080 0.0384 0.0011 332 55 250 6 243 7

8 69.01 156.83 0.44 0.0561 0.0016 0.2970 0.0097 0.0386 0.0011 457 61 264 8 244 7

9 63.96 163.54 0.39 0.0509 0.0014 0.2715 0.0084 0.0384 0.0011 237 61 244 7 243 7

146

10 117.56 312.02 0.38 0.0516 0.0015 0.2740 0.0092 0.0388 0.0011 267 65 246 7 245 7

11 114.05 328.36 0.35 0.0538 0.0018 0.2796 0.0108 0.0393 0.0012 361 73 250 9 248 7

12 85.61 178.22 0.48 0.0512 0.0017 0.2698 0.0100 0.0382 0.0011 251 72 243 8 242 7

13 113.56 259.71 0.44 0.0506 0.0014 0.2883 0.0091 0.0404 0.0012 223 61 257 7 255 7

14 140.31 332.36 0.42 0.0517 0.0015 0.2746 0.0090 0.0386 0.0011 273 63 246 7 244 7

15 161.17 332.06 0.49 0.0516 0.0014 0.2823 0.0089 0.0400 0.0012 269 61 253 7 253 7

16 81.41 224.14 0.36 0.0501 0.0012 0.2773 0.0080 0.0395 0.0011 201 56 249 6 250 7

17 105.03 218.10 0.48 0.0547 0.0019 0.2962 0.0117 0.0391 0.0012 398 73 263 9 247 7

XNG-G01

1 264.20 269.24 0.98 0.0529 0.0036 0.2866 0.0175 0.0399 0.0007 324 153 256 14 252 4

2 380.02 451.43 0.84 0.0517 0.0031 0.2848 0.0161 0.0402 0.0007 272 139 254 13 254 5

3 273.65 348.48 0.79 0.0537 0.0034 0.2908 0.0189 0.0387 0.0007 367 144 259 15 245 4

4 506.70 472.55 1.07 0.0499 0.0028 0.2827 0.0163 0.0405 0.0007 191 131 253 13 256 4

5 559.26 495.15 1.13 0.0529 0.0032 0.2874 0.0160 0.0393 0.0006 324 132 257 13 249 4

6 366.65 404.58 0.91 0.0542 0.0028 0.2979 0.0145 0.0398 0.0007 389 121 265 11 252 4

7 412.71 417.69 0.99 0.0549 0.0034 0.3005 0.0177 0.0394 0.0006 409 137 267 14 249 4

8 216.53 267.69 0.81 0.0554 0.0034 0.3012 0.0192 0.0387 0.0008 428 139 267 15 245 5

9 349.68 402.75 0.87 0.0518 0.0030 0.2875 0.0155 0.0399 0.0006 276 133 257 12 252 4

147

10 1106.32 813.08 1.36 0.0505 0.0022 0.2958 0.0125 0.0420 0.0007 217 100 263 10 265 4

11 534.95 565.54 0.95 0.0509 0.0030 0.2776 0.0151 0.0396 0.0008 235 132 249 12 250 5

12 315.55 360.58 0.88 0.0563 0.0034 0.2990 0.0183 0.0386 0.0007 465 133 266 14 244 5

13 216.98 201.37 1.08 0.0480 0.0038 0.2648 0.0200 0.0403 0.0007 98 178 239 16 255 4

14 655.48 527.67 1.24 0.0514 0.0028 0.2808 0.0151 0.0398 0.0008 257 124 251 12 251 5

15 180.11 251.88 0.72 0.0530 0.0040 0.2828 0.0190 0.0395 0.0007 332 172 253 15 250 4

16 189.57 276.60 0.69 0.0468 0.0033 0.2662 0.0193 0.0410 0.0011 39 172 240 15 259 7

17 637.30 670.31 0.95 0.0558 0.0026 0.3027 0.0142 0.0388 0.0006 443 101 268 11 245 3

BS-G01

1 169.91 321.99 0.53 0.0522 0.0043 0.2469 0.0172 0.0350 0.0008 295 187 224 14 222 5

2 291.03 499.69 0.58 0.0472 0.0050 0.2254 0.0216 0.0346 0.0009 58 237 206 18 219 5

3 259.26 595.97 0.44 0.0467 0.0043 0.2271 0.0225 0.0351 0.0007 35 207 208 19 222 4

4 213.31 482.28 0.44 0.0561 0.0048 0.2690 0.0216 0.0349 0.0007 457 190 242 17 221 4

5 256.60 588.53 0.44 0.0512 0.0043 0.2476 0.0195 0.0347 0.0009 250 188 225 16 220 6

6 247.34 589.66 0.42 0.0461 0.0026 0.2228 0.0131 0.0347 0.0007 400 200 204 11 220 4

7 218.57 500.93 0.44 0.0487 0.0030 0.2353 0.0147 0.0350 0.0007 132 141 215 12 222 4

8 333.51 670.80 0.50 0.0539 0.0037 0.2574 0.0164 0.0349 0.0008 369 158 233 13 221 5

9 373.69 924.39 0.40 0.0505 0.0029 0.2435 0.0141 0.0349 0.0007 217 131 221 11 221 4

148

10 168.45 395.95 0.43 0.0533 0.0094 0.2507 0.0335 0.0346 0.0016 343 359 227 27 220 10

11 396.47 647.45 0.61 0.0470 0.0074 0.2657 0.0394 0.0351 0.0020 56 331 239 32 223 12

12 306.68 695.15 0.44 0.0537 0.0032 0.2572 0.0154 0.0346 0.0006 367 133 232 12 219 4

13 135.35 373.10 0.36 0.0562 0.0059 0.2568 0.0206 0.0348 0.0009 461 231 232 17 221 6

HD-G01

1 539.84 1338.32 0.40 0.0527 0.0010 0.2416 0.0054 0.0347 0.0010 318 43 220 4 220 6

2 214.97 476.66 0.45 0.0510 0.0013 0.2281 0.0068 0.0329 0.0010 241 59 209 6 209 6

3 777.43 1140.69 0.68 0.0534 0.0012 0.2362 0.0062 0.0342 0.0010 344 51 215 5 217 6

4 175.95 469.87 0.37 0.0506 0.0011 0.2301 0.0056 0.0333 0.0010 224 48 210 5 211 6

5 593.22 1477.53 0.40 0.0535 0.0011 0.2427 0.0056 0.0348 0.0010 351 45 221 5 220 6

6 445.11 966.16 0.46 0.0535 0.0010 0.2401 0.0054 0.0343 0.0010 348 43 219 4 218 6

7 193.15 915.92 0.21 0.0517 0.0011 0.2257 0.0055 0.0323 0.0009 274 48 207 5 205 6

8 89.88 239.30 0.38 0.0511 0.0016 0.2262 0.0080 0.0326 0.0010 245 70 207 7 207 6

9 162.61 302.37 0.54 0.0540 0.0020 0.2409 0.0100 0.0346 0.0011 372 80 219 8 219 7

10 174.35 539.15 0.32 0.0500 0.0012 0.2252 0.0060 0.0325 0.0010 196 53 206 5 206 6

11 116.92 311.33 0.38 0.0509 0.0013 0.2326 0.0068 0.0337 0.0010 235 57 212 6 214 6

12 386.73 798.57 0.48 0.0520 0.0011 0.2343 0.0057 0.0336 0.0010 285 48 214 5 213 6

13 131.35 275.50 0.48 0.0516 0.0015 0.2229 0.0071 0.0325 0.0010 267 63 204 6 206 6

149

14 147.03 318.05 0.46 0.0544 0.0014 0.2381 0.0070 0.0320 0.0010 385 56 217 6 203 6

15 258.70 519.17 0.50 0.0517 0.0011 0.2331 0.0058 0.0335 0.0010 271 49 213 5 213 6

16 602.71 1307.11 0.46 0.0525 0.0010 0.2317 0.0052 0.0334 0.0010 306 43 212 4 212 6

17 216.96 481.16 0.45 0.0512 0.0011 0.2385 0.0057 0.0340 0.0010 250 47 217 5 216 6

18 166.09 322.19 0.52 0.0519 0.0013 0.2382 0.0067 0.0340 0.0010 281 55 217 5 216 6

19 186.63 438.40 0.43 0.0513 0.0011 0.2278 0.0058 0.0318 0.0009 256 50 208 5 202 6

20 254.73 761.21 0.33 0.0517 0.0011 0.2231 0.0054 0.0322 0.0009 272 48 205 5 204 6

21 384.18 793.15 0.48 0.0522 0.0013 0.2392 0.0067 0.0342 0.0010 296 54 218 5 217 6

Note: Errors are 1σ representing standard deviatio

150

Table 1.3 Geochemical data for the Linxi granitoids

XNG XNG XNG XNG XNG XNG XNG Sample B-1-1 B-1-2 B-1-3 B-1-4 B-1-5 B-2-1 B-2-2 B-2-3 B-2-4 B-2-5 BS-1 BS-2 BS-3 BS-4 BS-5 BS-6 HD-1 HD-2 HD-3 HD-4 HD-5 -1 -2 -3 -4 -5 -6 -7

Major elements (wt.%)

SiO2 66.08 65.80 66.76 65.29 65.31 65.46 67.34 66.78 63.88 64.73 72.91 72.09 71.02 71.17 69.31 71.71 72.49 76.64 75.36 76.02 74.24 76.98 74.64 76.00 75.74 76.67 77.09 77.34

Al2O3 16.20 16.31 16.46 16.84 16.71 15.56 15.51 15.60 15.82 15.79 13.21 14.09 14.06 13.94 15.17 14.17 13.89 12.15 13.00 12.86 13.50 12.25 13.20 12.31 12.82 12.28 11.84 11.78

Fe2O3 3.09 3.16 3.16 3.70 3.42 3.82 3.14 3.35 4.26 3.97 1.31 1.32 1.39 1.37 1.65 1.40 1.30 1.18 1.36 0.97 0.96 1.01 1.49 1.47 1.17 1.22 1.27 1.47

FeO 1.04 2.83 2.79 3.29 2.93 3.42 2.39 2.28 3.17 2.95 0.86 0.84 0.87 0.84 0.98 0.79 0.97 1.00 1.05 0.84 0.80 0.90 1.25 1.27 1.00 1.04 1.01 1.26

MgO 1.32 1.50 1.43 1.60 1.51 1.91 1.62 1.76 2.17 2.02 0.35 0.38 0.40 0.39 0.46 0.41 0.36 0.14 0.14 0.13 0.07 0.11 0.11 0.15 0.16 0.16 0.15 0.18

Na2O 3.27 3.08 3.26 3.17 3.32 3.18 2.08 2.25 3.44 3.30 3.45 4.02 4.20 4.16 4.93 4.12 4.03 0.56 0.59 0.63 0.50 0.52 0.63 0.70 0.47 0.35 0.19 0.21

CaO 4.63 4.62 5.30 5.11 4.97 4.06 4.17 4.17 3.99 4.04 0.86 1.20 1.35 1.35 1.98 1.32 1.14 2.82 3.52 3.76 3.04 2.63 3.66 3.28 3.33 3.00 2.83 3.00

K2O 2.00 1.95 1.52 1.53 1.99 3.35 3.91 3.68 3.36 3.37 6.11 5.23 5.30 5.35 4.35 5.16 5.12 5.14 4.75 4.43 6.67 5.28 5.09 5.03 5.33 5.31 5.73 5.19

MnO 0.06 0.06 0.06 0.06 0.06 0.06 0.04 0.05 0.06 0.06 0.02 0.02 0.02 0.02 0.03 0.03 0.02 0.03 0.04 0.02 0.02 0.02 0.04 0.02 0.01 0.01 0.01 0.01

TiO2 0.44 0.47 0.49 0.55 0.51 0.71 0.58 0.62 0.82 0.74 0.18 0.21 0.21 0.21 0.25 0.21 0.19 0.09 0.10 0.07 0.07 0.06 0.10 0.14 0.14 0.14 0.15 0.13

P2O5 0.13 0.13 0.13 0.16 0.15 0.16 0.14 0.16 0.18 0.17 0.04 0.05 0.05 0.05 0.06 0.05 0.04 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.02

LOI 2.69 2.83 1.41 1.98 2.02 1.68 1.46 1.57 1.97 1.71 1.04 1.30 1.49 1.46 1.72 1.35 1.31 1.14 1.09 1.05 0.85 1.05 0.97 0.77 0.79 0.83 0.70 0.66

Total 99.91 99.91 99.98 99.99 99.98 99.95 100.0 99.98 99.96 99.90 99.48 99.90 99.48 99.47 99.91 99.92 99.90 99.90 99.96 99.94 99.93 99.94 99.94 99.90 99.99 99.98 99.98 99.99

151

TFeO 3.82 5.67 5.63 6.62 6.01 6.86 5.22 5.29 7.00 6.52 2.04 2.03 2.12 2.07 2.46 2.05 2.14 2.06 2.27 1.71 1.66 1.81 2.59 2.59 2.05 2.14 2.15 2.58

Mg# 38.17 32.08 31.20 30.16 30.99 33.23 35.69 37.26 35.63 35.62 23.27 25.08 25.02 25.30 25.01 26.09 23.26 11.03 9.65 11.61 7.37 9.72 6.93 9.59 11.89 11.60 10.87 10.85

Trace elements(ppm)

Cr 31 33.2 33.9 38.7 35.9 34.1 30.2 33.1 37.1 35.8 2.33 2.68 3.71 3.68 1.82 3.13 2.55 2.42 2.39 2.05 1.96 1.81 1.9 0.73 0.86 0.68 2.02 0.60

Ni 5.99 6.45 6.12 8.29 7.15 23.3 10.8 11.7 27.8 24.9 3.82 1.73 4.42 4.22 2.15 2.24 1.66 20.1 20.3 19.3 17.5 17.2 15.1 0.53 0.62 0.4 0.461 0.32

Sc 11.7 9.01 6.43 6.75 13.7 8.81 7.59 7.98 11.1 10.6 2.3 1.76 2.18 1.92 2.07 1.78 1.82 3.47 4.1 3.52 2.51 3.37 4.64 4.78 2.99 2.55 3.81 1.92

Co 6.45 6.41 6.75 7.33 7.42 11.2 7 7.52 12.9 12.5 1.88 1.76 1.86 1.83 2.44 2.11 1.78 338 352 312 282 278 265 0.83 0.72 0.65 0.31 0.21

V 47.2 46 47.5 51.3 56.9 56.3 43.2 46.2 66.2 60.3 15.5 17.1 25.6 21 18.1 22.8 17.7 3.41 4.19 3.44 3.34 2.93 3.3 6.65 7.57 5.69 7.34 7.95

Cu 10.5 6.62 3.64 4.84 7 18.9 9.11 12.3 23.2 21.2 8.35 18.7 72.3 36.6 52.5 26 67.3 1.72 1.1 8.17 2.06 2.21 1 1.3 1.11 1.31 1.67 2.27

Zn 71.2 69.9 77.2 81.8 81.1 58.9 52.9 59 64.9 63.1 33.1 24.7 27.7 29.8 35.2 26.4 25.8 26.1 37.9 25.1 21.7 20.9 35 23.9 17.9 19.6 16.3 17.6

Ga 23.3 22.7 24.7 24.9 25.3 19.2 18.5 18.9 18.8 19.7 15.1 15.1 15.9 15.8 16.7 15.4 15 26.5 27.5 25.8 25.4 26 30.6 19.7 19.9 19.6 18.2 19.7

Ba 186 145 85.3 78.4 182 515 622 635 512 597 768 767 706 729 660 695 636 31.1 57.1 21.8 50.9 29.4 34.6 101 107 140 166 154

Rb 126 130 117 121 131 101 143 135 98.6 102 119 110 115 111 103 109 103 632 595 541 862 698 668 170 157 161 165 155

Th 11.5 14.4 9.08 12.5 13 16.9 18.1 18.1 14.4 16.1 11.6 8.52 8.34 8.99 6.12 7.97 7.07 39.7 41.2 58.7 24.6 46.1 52.4 30 21.1 22.3 21.1 26

U 6.63 13.6 6.25 7 7.45 4.88 5.08 5.06 4.33 4.64 2.43 2.15 1.93 2.37 1.83 1.98 1.54 13.8 20.7 24 11.6 17.5 20.6 7.25 7.96 6.4 6.68 6.19

Nb 10.1 12.4 13.8 11.1 12.3 8.45 7.91 8.04 8.2 8.77 3.99 3.22 3.57 3.28 2.8 2.95 2.98 29.2 31.9 24.7 22.3 26.4 34.7 8.85 6.82 7.18 6.79 6.22

Ta 1.44 2.11 1.9 1.01 1.75 1.05 1.02 1.04 0.82 0.84 0.43 0.33 0.34 0.33 0.26 0.26 0.23 5.04 4.83 4.53 6.56 4.78 5.18 0.89 0.72 0.67 0.65 0.64

152

Sr 240 217 231 222 248 371 400 417 381 386 241 212 218 214 266 235 223 10.2 14.2 11 14.3 9.44 13.8 33.8 36.3 35.4 30.9 33

Zr 155 175 186 220 202 231 248 247 233 231 94.4 58.8 59.6 62.4 40.8 64.6 63.3 119 130 149 59.4 120 141 104 101 118 90.2 106

Hf 4.4 5 5.32 6.33 6.27 6.73 6.82 7.03 6.75 6.27 3.59 2.4 2.33 2.62 1.56 2.35 2.18 6.63 7.89 8.42 2.9 7.43 8.14 4.42 3.93 4.25 3.43 4.42

Y 15.7 18.9 17.8 14.6 18.1 24 20.8 21.3 24.7 23.8 8.17 6.36 7.38 7.43 5.66 6.6 5.09 90.6 120 120 82.3 96.5 130 49.5 36.8 37 36.2 37.4

Pb 17.6 16.6 15.3 14.8 17.5 18.3 18.1 19.5 17.3 17.8 23.1 18.3 19 21.5 16.6 18 19.5 24.4 38 32.9 37.1 29.9 31.7 24.3 25.8 28.7 22.7 18.8

La 13.6 14.2 12.1 15.8 14 29.8 30.5 30.8 29.2 29.4 27.9 18.5 19.9 18.9 18.7 19.3 21.4 29 30.2 24.8 22.2 25.6 33.4 48 49.6 68.4 48.8 81.7

Ce 27.4 24.7 24.8 31.9 28.7 59 59.6 60.7 57.6 58.7 46.9 31.5 34.8 32.2 31.7 32.6 35.2 70 73.2 60 53.2 61.8 82.4 103 105 145 105 166

Pr 3.43 3.68 3.23 3.86 3.58 7.19 7.24 7.42 7.12 7.15 5.06 3.43 3.9 3.56 3.47 3.56 3.94 9 9.24 7.74 6.91 8.29 10.8 12.9 13.4 17.8 13.1 19.8

Nd 13.7 15.1 13 14.5 14.6 27.6 27.4 28.2 27.8 27.5 16.5 11.5 12.7 12.2 11.7 11.9 12.9 32.6 32.2 28.7 24.2 30.5 38.3 48.5 50.2 66.1 50.4 74.1

Sm 3.07 3.74 3.23 2.94 3.32 5.3 5.18 5.42 5.56 5.26 2.48 1.85 2.09 2.04 1.74 1.81 1.89 8.37 8.68 7.74 6.61 8.58 10.6 10.7 10.2 13 10.8 14.2

Eu 0.69 0.71 0.66 0.67 0.72 1.03 0.93 0.94 1.11 1.02 0.65 0.60 0.57 0.58 0.73 0.60 0.59 0.11 0.11 0.08 0.12 0.11 0.09 0.32 0.37 0.46 0.45 0.56

Gd 3.03 3.61 3.2 2.83 3.46 4.27 4.33 4.35 4.9 4.54 2.02 1.54 1.75 1.58 1.39 1.51 1.39 7.35 8.96 7.65 6.66 8.76 11.1 9.86 8.37 10.6 9.78 11.3

Tb 0.48 0.63 0.47 0.46 0.66 0.76 0.72 0.73 0.91 0.77 0.29 0.22 0.24 0.25 0.21 0.21 0.19 1.63 2.13 1.83 1.47 1.92 2.62 1.9 1.46 1.61 1.62 1.8

Dy 2.53 3.14 3.32 2.59 2.93 4.21 3.88 4.13 4.79 4.83 1.31 1.04 1.14 1.15 0.961 1.03 0.804 13.4 18.2 15.7 12.9 14.1 18.5 10.9 8.48 8.32 8.43 8.76

Ho 0.50 0.54 0.61 0.51 0.60 0.85 0.79 0.81 0.93 0.94 0.26 0.2 0.23 0.21 0.18 0.19 0.16 2.7 4.18 3.29 2.42 2.93 3.77 2.03 1.36 1.49 1.52 1.48

Er 1.5 1.66 1.48 1.35 1.82 2.21 2.02 1.95 2.45 2.39 0.69 0.53 0.61 0.62 0.48 0.55 0.46 8.72 13.3 12 8.17 9.91 13.4 5.03 3.67 3.56 3.76 3.55

Tm 0.22 0.32 0.31 0.23 0.34 0.35 0.37 0.40 0.42 0.44 0.14 0.11 0.12 0.12 0.09 0.11 0.08 1.55 2.47 2.22 1.51 1.68 2.15 0.90 0.59 0.60 0.64 0.56

153

Yb 1.57 2.05 1.78 1.49 2.06 2.11 2 2.11 2.49 2.29 0.94 0.70 0.76 0.72 0.58 0.67 0.56 12 17.2 17.1 12.7 12 16.2 4.73 3.65 3.81 3.44 3.78

Lu 0.23 0.31 0.29 0.23 0.29 0.40 0.33 0.35 0.44 0.39 0.13 0.09 0.10 0.09 0.08 0.09 0.08 1.89 2.64 2.72 1.76 2.03 2.37 0.69 0.53 0.49 0.49 0.47

ΣREE 198.3 222.7 191.6 160.8 188.2 245.7 71.9 74.4 68.5 79.4 77.1 259.5 256.9 341.2 258.2 388.1 145.1 145.3 148.3 145.7 145.6 105.3 71.8 78.9 74.2 72.0 74.1 79.7

L/H 6.15 5.07 4.97 7.20 5.34 8.58 9.06 9.00 7.41 7.78 17.23 15.22 14.93 14.67 17.14 16.00 20.35 3.03 2.22 2.06 2.38 2.53 2.50 6.20 8.14 10.19 7.70 11.24

LaN/YbN 5.88 4.71 4.62 7.20 4.62 9.59 10.36 9.92 7.97 8.72 20.27 17.85 17.76 17.73 21.83 19.66 26.15 1.64 1.19 0.99 1.19 1.45 1.40 6.89 9.23 12.20 9.64 14.68

Eu/Eu* 0.68 0.58 0.62 0.70 0.64 0.64 0.58 0.57 0.63 0.62 0.85 1.05 0.89 0.95 1.37 1.07 1.06 0.04 0.04 0.03 0.05 0.04 0.03 0.09 0.12 0.12 0.13 0.13

Ce/Ce* 0.95 0.81 0.94 0.96 0.96 0.95 0.94 0.94 0.94 0.95 0.89 0.89 0.90 0.89 0.89 0.89 0.87 1.04 1.05 1.04 1.03 1.02 1.04 0.98 0.97 0.98 0.99 0.97

2+ 2+ 2+ Note: LOI = loss on ignition, TFeO= total FeO, Mg# = 100×molar Mg / (Mg + Fe ), L/H = ΣLREE/ΣHREE, Eu/Eu* = 2×EuN/(SmN+GdN), Ce/Ce* =

2×CeN/(LaN+PrN), N = chondrite-normalized concentrations (Sun and McDonough 1989)

154

Table 1.4: Hf isotope data for zircons from the Linxi granitoids

176 177 176 177 176 177 176 177 No. T(Ma) Yb/ Hf 2σ Lu/ Hf 2σ Hf/ Hf 2σ Hf/ Hf(t) εHf(0) εHf(t) TDM(Ma) fLu-Hf TDM2(Ma)

BSFZ-G01

1 252 0.027266 0.000502 0.000687 0.000011 0.282890 0.000019 0.282887 4.2 9.6 508 -0.98 664

2 252 0.050657 0.001039 0.001330 0.000022 0.282910 0.000021 0.282904 4.9 10.2 489 -0.96 625

3 252 0.037218 0.000427 0.000972 0.000012 0.282878 0.000019 0.282873 3.7 9.1 530 -0.97 694

4 252 0.042406 0.000628 0.001114 0.000017 0.282860 0.000021 0.282854 3.1 8.5 558 -0.97 737

5 252 0.034634 0.001301 0.000908 0.000029 0.282833 0.000021 0.282829 2.1 7.5 593 -0.97 796

6 252 0.040548 0.001129 0.001099 0.000026 0.282840 0.000022 0.282835 2.4 7.8 585 -0.97 781

7 252 0.055910 0.000828 0.001486 0.000023 0.282883 0.000025 0.282876 3.9 9.2 529 -0.96 687

8 252 0.076888 0.001742 0.001937 0.000044 0.282862 0.000026 0.282853 3.2 8.4 567 -0.94 740

9 252 0.040701 0.000606 0.001087 0.000017 0.282891 0.000024 0.282886 4.2 9.6 513 -0.97 667

10 252 0.031383 0.000235 0.000846 0.000008 0.282931 0.000024 0.282927 5.6 11.0 453 -0.97 572

11 252 0.028415 0.000178 0.000756 0.000004 0.282880 0.000021 0.282877 3.8 9.2 523 -0.98 687

12 252 0.102359 0.006579 0.002287 0.000131 0.282897 0.000027 0.282886 4.4 9.6 521 -0.93 665

BSFZ-G02

1 246.2 0.029303 0.000273 0.000763 0.000005 0.282888 0.000022 0.282884 4.1 9.4 513 -0.98 674

155

2 246.2 0.025827 0.000323 0.000673 0.000008 0.282919 0.000024 0.282916 5.2 10.5 468 -0.98 602

3 246.2 0.063599 0.004159 0.001690 0.000112 0.282916 0.000025 0.282909 5.1 10.2 485 -0.95 618

4 246.2 0.028864 0.000245 0.000753 0.000005 0.282882 0.000025 0.282879 3.9 9.2 521 -0.98 686

5 246.2 0.023759 0.000234 0.000636 0.000008 0.282947 0.000024 0.282944 6.2 11.5 427 -0.98 537

6 246.2 0.018091 0.000170 0.000489 0.000003 0.282848 0.000022 0.282846 2.7 8.0 565 -0.99 761

7 246.2 0.016920 0.000159 0.000466 0.000005 0.282911 0.000029 0.282909 4.9 10.3 476 -0.99 617

8 246.2 0.023126 0.000524 0.000606 0.000011 0.282909 0.000023 0.282907 4.9 10.2 481 -0.98 623

9 246.2 0.025679 0.000265 0.000687 0.000007 0.282899 0.000024 0.282895 4.5 9.8 497 -0.98 648

10 246.2 0.031156 0.000313 0.000809 0.000009 0.282924 0.000024 0.282920 5.4 10.7 462 -0.98 592

11 246.2 0.025984 0.000878 0.000664 0.000019 0.282913 0.000024 0.282910 5.0 10.3 476 -0.98 615

12 246.2 0.019259 0.000042 0.000515 0.000002 0.282908 0.000024 0.282906 4.8 10.2 481 -0.98 624

13 246.2 0.029515 0.002351 0.000758 0.000055 0.282896 0.000026 0.282892 4.4 9.7 502 -0.98 655

14 246.2 0.025838 0.000399 0.000696 0.000008 0.282911 0.000033 0.282907 4.9 10.2 480 -0.98 621

15 246.2 0.027959 0.000650 0.000747 0.000020 0.282960 0.000025 0.282956 6.6 11.9 411 -0.98 511

XNG-G01

1 251.1 0.038013 0.001128 0.001230 0.000032 0.282911 0.000021 0.282905 4.9 10.2 487 -0.96 624

2 251.1 0.033816 0.000853 0.001129 0.000038 0.282807 0.000026 0.282802 1.2 6.6 633 -0.97 857

156

3 251.1 0.030720 0.000991 0.000990 0.000023 0.282918 0.000024 0.282913 5.2 10.5 474 -0.97 605

4 251.1 0.040196 0.000959 0.001253 0.000026 0.282866 0.000021 0.282860 3.3 8.6 552 -0.96 726

5 251.1 0.067107 0.003367 0.002105 0.000098 0.282906 0.000022 0.282896 4.7 9.9 505 -0.94 644

6 251.1 0.041108 0.001758 0.001346 0.000042 0.282921 0.000027 0.282915 5.3 10.6 473 -0.96 601

7 251.1 0.046717 0.001548 0.001411 0.000040 0.282809 0.000021 0.282803 1.3 6.6 634 -0.96 855

8 251.1 0.026934 0.001088 0.000895 0.000037 0.282934 0.000024 0.282930 5.7 11.1 449 -0.97 568

9 251.1 0.049938 0.001025 0.001651 0.000056 0.282962 0.000023 0.282954 6.7 12.0 418 -0.95 512

10 251.1 0.030771 0.001381 0.000963 0.000041 0.282951 0.000023 0.282947 6.3 11.7 425 -0.97 529

11 251.1 0.058686 0.000765 0.001848 0.000033 0.282962 0.000025 0.282953 6.7 11.9 421 -0.94 515

12 251.1 0.034945 0.001080 0.001120 0.000027 0.282918 0.000021 0.282913 5.2 10.5 474 -0.97 605

BS-G01

1 220.8 0.122950 0.001112 0.002867 0.000024 0.282885 0.000026 0.282873 4.0 8.4 547 -0.91 714

2 220.8 0.164905 0.014722 0.003695 0.000278 0.283007 0.000037 0.282992 8.3 12.6 373 -0.89 446

3 220.8 0.128576 0.013000 0.002596 0.000232 0.282986 0.000026 0.282975 7.6 12.0 394 -0.92 485

4 220.8 0.062866 0.002893 0.001511 0.000053 0.282984 0.000023 0.282978 7.5 12.1 384 -0.95 478

5 220.8 0.048731 0.000193 0.001245 0.000005 0.282969 0.000022 0.282964 7.0 11.6 404 -0.96 510

6 220.8 0.055036 0.001584 0.001348 0.000029 0.282969 0.000024 0.282964 7.0 11.6 405 -0.96 511

157

7 220.8 0.042301 0.000771 0.001121 0.000016 0.282981 0.000023 0.282976 7.4 12.1 385 -0.97 482

8 220.8 0.237672 0.034282 0.005472 0.000770 0.283055 0.000029 0.283032 10.0 14.1 317 -0.84 355

9 220.8 0.105757 0.004376 0.002751 0.000098 0.282875 0.000033 0.282863 3.6 8.1 561 -0.92 737

10 220.8 0.050691 0.002732 0.001303 0.000062 0.282938 0.000025 0.282933 5.9 10.5 448 -0.96 580

11 220.8 0.058872 0.002628 0.001484 0.000057 0.282981 0.000027 0.282975 7.4 12.0 389 -0.96 486

12 220.8 0.060168 0.001503 0.001453 0.000031 0.282889 0.000025 0.282883 4.1 8.8 521 -0.96 693

13 220.8 0.038410 0.001114 0.001032 0.000032 0.282931 0.000024 0.282927 5.6 10.3 455 -0.97 593

14 220.8 0.047424 0.001023 0.001188 0.000020 0.282898 0.000024 0.282894 4.5 9.2 504 -0.96 669

HD-G01

1 211.4 0.091662 0.001580 0.002582 0.000047 0.282941 0.000019 0.282931 6.0 10.3 460 -0.92 591

2 211.4 0.041054 0.001205 0.001098 0.000024 0.282975 0.000024 0.282970 7.2 11.7 394 -0.97 501

3 211.4 0.061907 0.000964 0.001614 0.000022 0.283028 0.000029 0.283021 9.0 13.5 323 -0.95 386

4 211.4 0.136347 0.001886 0.004085 0.000075 0.282914 0.000019 0.282898 5.0 9.1 522 -0.88 665

5 211.4 0.053373 0.000702 0.001386 0.000016 0.282907 0.000023 0.282901 4.8 9.2 494 -0.96 657

6 211.4 0.083603 0.000311 0.002134 0.000010 0.282909 0.000023 0.282900 4.8 9.2 502 -0.94 660

7 211.4 0.073157 0.002850 0.001884 0.000073 0.282850 0.000025 0.282843 2.8 7.2 583 -0.94 789

8 211.4 0.040930 0.000026 0.001073 0.000002 0.282974 0.000022 0.282970 7.2 11.7 394 -0.97 501

158

9 211.4 0.038302 0.000099 0.001008 0.000002 0.282893 0.000023 0.282889 4.3 8.8 509 -0.97 684

10 211.4 0.029232 0.000845 0.000786 0.000023 0.282977 0.000023 0.282974 7.3 11.8 387 -0.98 492

11 211.4 0.053094 0.000377 0.001380 0.000006 0.282960 0.000023 0.282954 6.6 11.1 419 -0.96 538

12 211.4 0.034904 0.001001 0.000944 0.000026 0.282929 0.000024 0.282926 5.6 10.1 457 -0.97 602

13 211.4 0.054828 0.000249 0.001411 0.000008 0.282890 0.000023 0.282884 4.2 8.6 519 -0.96 695

176 177 176 177 176 177 176 177 λt 176 177 176 177 λt Note: εHf(0)=(( Hf/ Hf)S/( Hf/ Hf)CHUR-1)×10000, εHf(t)=(( Hf/ Hf)S-( Lu/ Hf)S×(e -1))/(( Hf/ Hf)CHUR-( Lu/ Hf)CHUR×(e -1))-1)×10000 ；

176 177 176 177 176 177 176 177 176 177 176 177 TDM1=1/λ×ln[1+(( Hf/ Hf)S-( Hf/ Hf)DM)/(( Lu/ Hf)S-( Lu/ Hf)DM)]；TDM2=TDM1-(TDM1-t)(fCC-fS)/(fCC-fDM)；fLu/Hf=( Lu/ Hf)S /( Lu/ Hf)CHUR-1；

176 177 176 177 176 177 176 177 ( Lu/ Hf)CHUR=0.0332, ( Hf/ Hf)CHUR=0.282772 (Blichert-Toft and Albarède 1997), ( Lu/ Hf)DM=0.0384, ( Hf/ Hf)DM=0.28325 (Griffin et al. 2000), 176 177 176 177 176 177 176 177 -11 -1 fCC=[( Lu/ Hf)mean crust/( Lu/ Hf)CHUR]-1, fDM=[( Lu/ Hf)DM/( Lu/ Hf)CHUR]-1, λ=1.867×10 year (Söderlund et al. 2004), t=crystallization age of zircon. The 2σ represents standard deviation.

159

Table 1.5 Zircon U–Pb ages of granitoids from the Linxi area and adjacent regions.

No. Sample Pluton Lithology Method Age(Ma) References

1 G0206-1 Yonghetun Monzodiorite LA-ICPMS 127 ± 2 Ge et al. 2005

2 G0206-2 Yonghetun Porphyrite LA-ICPMS 128 ± 3 Ge et al. 2005

3 G0208-1 Qingshan Monzogranite LA-ICPMS 138 ± 3 Ge et al. 2005

4 G0208-3 Qingshan Monzogranite LA-ICPMS 133 ± 3 Ge et al. 2005

5 G0211-1 Dashizhai Monzogranite LA-ICPMS 176 ± 13 Ge et al. 2005

6 G0211-4 Dashizhai Monzogranite LA-ICPMS 182 ± 3 Ge et al. 2005

7 G0213-4 Jingyang Monzogranite LA-ICPMS 176 ± 4 Ge et al. 2005

8 G0215-4 Suolun Alkali feldspar granite LA-ICPMS 126 ± 2 Ge et al. 2005

9 G0217-1 Chagan Alkali feldspar granite LA-ICPMS 229 ± 3 Ge et al. 2005

10 G0217-2 Chagan Alkali feldspar granite LA-ICPMS 236 ± 2 Ge et al. 2005

11 MX16 Xilinhot Alkali feldspar granite SHRIMP 276 ± 2 Shi et al. 2004

12 MXA12 Xilingele Garnet granite SHRIMP 316 ± 3 Shi et al. 2003

13 LW97066 Ma 0 anzi Syenogranite TIMS 149 ± 2 Liu et al. 2005

14 LW97077 Longtoushan I Granodiorite TIMS 226 ± 4 Liu et al. 2005

15 WL53063 Xiaochengzi Granodiorite TIMS 111 ± 1 Liu et al. 2005

160

16 WL60423 Yelaigai Syenogranite TIMS 148 ± 1 Liu et al. 2005

17 WL60428 Longtoushan II Syenogranite TIMS 117 ± 4 Liu et al. 2005

18 ELMT-04 Herimu Tai Granite LA-ICPMS 136.9±1.7 Pei et al. 2017

19 XNG-G01 Xinangou Monzogranite LA-ICPMS 252.1 ± 2.6 This study

20 BSFZ-G01 Banshifangzi Granodiorite LA-ICPMS 252±3 This study

21 BSFZ-G02 Banshifangzi Granodiorite porphyry LA-ICPMS 246.3 ± 3.3 This study

22 BS-G01 Baoshan Monzogranite LA-ICPMS 220.8 ± 2.7 This study

23 HD-G01 Hada Biotite granite LA-ICPMS 211.4 ±2.6 This study

24 BL-4 Baogeda Ula Biotite granite SHRIMP 241±3 Liu et al. 2012a

25 D98-1 Shuangjingzi 2-mica granite SHRIMP 229 ± 4 Li and Gao, 2007

26 D105-3 Shuangjingzi 2-mica granite SHRIMP 254 ± 4 Li and Gao, 2007

27 42-79 Jinxing Quartz diorite LA-ICPMS 322 ± 2 Liu et al. 2009

28 38-72 Daqihundi Quartz diorite LA-ICPMS 325 ± 3 Liu et al. 2009

29 Xp52Tw Meilindaba Quartz diorite SHRIMP 315 ± 5 Bao et al. 2007

30 QTw Wulangou Quartz diorite SHRIMP 315 ± 4 Bao et al. 2007

31 Xp4Tw Baiyingaole Quartz diorite SHRIMP 323 ± 4 Bao et al. 2007

32 11X03-4 Andesite LA-ICPMS 253±3 Gao et al. 2016

161

33 11X07-1 Andesite LA-ICPMS 251±2 Gao et al. 2016

34 11X04-1 Andesite LA-ICPMS 252±1 Gao et al. 2016

35 11RJ-2 Renjiayingzi Pyroxene diorite LA-ICPMS 138±1 Li et al. 2013b

36 11RJ-5 Renjiayingzi Tonalite SHRIMP 134±2 Li et al. 2013b

37 11RJ-11 Renjiayingzi Monzogranite LA-ICPMS 126±1 Li et al. 2013b

38 11XL-5.2 Beidashan Granodiorite SHRIMP 277±3 Li et al. 2016b

39 11SH-3 Shahutong Granodiorite SHRIMP 275±3 Li et al. 2016b

40 XL922-2 Beikeli Granodiorite SHRIMP 255±2 Li et al. 2016a

41 XL921-14 Baiyinwendu Granodiorite SHRIMP 251±2 Li et al. 2016a

42 XL920-8 Sumutai Granodiorite SHRIMP 255±2 Li et al. 2016a

43 11SH-5 Salihada Granodiorite SHRIMP 253±4 Li et al. 2016a

44 21DW-25 Hegenshan Granodioritic dyke SHRIMP 247 ± 2 Miao, 2003

45 21NMG-96 Dongfanghong Monzogranite SHRIMP 288 ± 6 Miao, 2003

46 21NMG-105 Baolige Monzogranite SHRIMP 296 ± 7 Miao, 2003

47 HG-68-1 Huanggang K-feldspar granite LA-ICPMS 145.3±1.6 Mei et al. 2015

48 05FW064 Jingpeng Monzogranite LA-ICPMS 141 ± 1 Wu et al. 2011a

49 05FW065 Jingpeng Monzogranite LA-ICPMS 140 ± 2 Wu et al. 2011a

162

50 05FW066 Jingpeng Quartz syenite LA-ICPMS 134 ± 1 Wu et al. 2011a

51 05FW080 Jingpeng Monzogranite LA-ICPMS 140 ± 2 Wu et al. 2011a

52 05FW083 Baiyinbangou Monzogranite LA-ICPMS 131 ± 2 Wu et al. 2011a

53 05FW092 Wanbao Mylonitic granite LA-ICPMS 237 ± 3 Wu et al. 2011a

54 05FW095 Wanbao Monzogranite LA-ICPMS 222 ± 3 Wu et al. 2011a

55 05FW096 Fangkuanggou Gneiss LA-ICPMS 274 ± 2 Wu et al. 2011a

56 05FW097 Xiahaisugou Gneiss LA-ICPMS 261 ± 6 Wu et al. 2011a

57 05FW098 Xiahaisugou Gneiss LA-ICPMS 259 ± 2 Wu et al. 2011a

58 05FW099 Yuanbaoshan Monzogranite LA-ICPMS 273 ± 3 Wu et al. 2011a

59 05FW102 Xiahaisugou Gneiss LA-ICPMS 237 ± 2 Wu et al. 2011a

60 05FW110 Shuangjing Diorite LA-ICPMS 246 ± 2 Wu et al. 2011a

61 05FW111 Shuangjing Gneiss LA-ICPMS 247 ± 3 Wu et al. 2011a

62 05FW116 Huanggangliang Syenogranite LA-ICPMS 132 ± 1 Wu et al. 2011a

63 05FW120 Dayingzi Monzogranite LA-ICPMS 132 ± 1 Wu et al. 2011a

64 05FW121 Huanggangliang Monzogranite LA-ICPMS 146 ± 2 Wu et al. 2011a

65 05FW124 Huanggangliang Syenogranite LA-ICPMS 141 ± 1 Wu et al. 2011a

66 05FW133 Donghuang Gabbro LA-ICPMS 252 ± 5 Wu et al. 2011a

163

67 05FW137 Banshantu Syenogranite LA-ICPMS 283 ± 2 Wu et al. 2011a

68 05FW140 Xinlin Granodiorite LA-ICPMS 241 ± 2 Wu et al. 2011a

69 05FW141 Chaoyanggou Monzogranite LA-ICPMS 132 ± 1 Wu et al. 2011a

70 05FW147 Chaoyanggou Monzogranite LA-ICPMS 142 ± 3 Wu et al. 2011a

71 05FW148 Chaoyanggou Dioritic enclave LA-ICPMS 150 ± 4 Wu et al. 2011a

72 05FW150 Mishengmiao Quartz diorite LA-ICPMS 303 ± 3 Wu et al. 2011a

73 05FW155 Qianjinchang Granodiorite LA-ICPMS 274 ± 1 Wu et al. 2011a

74 05FW161 Qianjinchang Granodiorite LA-ICPMS 275 ± 2 Wu et al. 2011a

75 05FW162 Daqingmuchang Monzogranite LA-ICPMS 274 ± 4 Wu et al. 2011a

76 05FW163 Beidashan Granodiorite LA-ICPMS 139 ± 1 Wu et al. 2011a

77 05FW167 Zhuanshanzi Monzogranite LA-ICPMS 246 ± 2 Wu et al. 2011a

78 05FW171 Beidashan Syenogranite LA-ICPMS 136 ± 2 Wu et al. 2011a

79 05FW174 Meilindaba Quartz diorite LA-ICPMS 301 ± 1 Wu et al. 2011a

80 05FW176 Dusheyetu Monzogranite LA-ICPMS 321 ± 1 Wu et al. 2011a

81 05FW178 Telegute Monzogranite LA-ICPMS 280 ± 3 Wu et al. 2011a

82 05FW180 Telegute Dioritic dyke LA-ICPMS 287 ± 3 Wu et al. 2011a

83 GW04158 Wulanmaodu Syenogranite LA-ICPMS 131 ± 1 Wu et al. 2011a

164

84 GW04162 Shabutai Monzogranite LA-ICPMS 129 ± 2 Wu et al. 2011a

85 GW04190 Jilasitai Alkali feldspar granite LA-ICPMS 135 ± 2 Wu et al. 2011a

86 GW04314 Fengshou Syenogranite LA-ICPMS 120 ± 2 Wu et al. 2011a

87 GW04360 Caishichangxi Monzogranite LA-ICPMS 120 ± 1 Wu et al. 2011a

88 GW04364 Shenshan Alkali feldspar granite LA-ICPMS 119 ± 1 Wu et al. 2011a

89 GW04369 Suolun Alkali feldspar granite LA-ICPMS 134 ± 2 Wu et al. 2011a

90 DSW4 Dongshanwan Granite porphyry SIMS 151.4±0.8 Zeng et al. 2015

91 HGL25 Huanggangliang Granite LA-ICPMS 139.96±0.87 Zhai et al. 2014b

92 HST-30 Hashitu Granite LA-ICPMS 147±1 Zhai et al. 2014a

93 HST-31 Hashitu Granite porphyry LA-ICPMS 143±2 Zhai et al. 2014a

94 130619-10 Guangxingyuan K-feldspar granite LA-ICPMS 257 ± 3 Zhao et al. 2016

95 110718-07 Guangxingyuan Syenite LA-ICPMS 265 ± 2 Zhao et al. 2016

165

Table 2.1 Major (wt%) element compositions of the Herimu Tai granites at the Shuitou fluorite deposit.

Sample No. SiO2 TiO2 Al2O3 TFe2O3 MnO MgO CaO Na2O K2O P2O5 LOI K2O+Na2O K2O/Na2O A/ NK A/CNK

ELMT-1 78.07 0.07 11.97 1.58 0.035 0.104 0.117 0.09 5.93 0.013 1.87 6.02 65.89 1.82 1.76

ELMT-2 78.52 0.066 10.8 1.38 0.042 0.151 0.172 0.081 7.36 0.019 1.37 7.44 90.86 1.33 1.28

ELMT-3 78.82 0.053 12.16 0.818 0.012 0.082 0.109 0.309 4.79 0.013 2.71 5.10 15.50 2.13 2.06

ELMT-4 79.26 0.067 11.57 1.31 0.03 0.139 0.126 0.1 5.21 0.024 0.49 5.31 52.10 1.99 1.91

ELMT-5 78.78 0.052 12 1.11 0.012 0.106 0.125 0.26 4.68 0.016 0.41 4.94 18.00 2.18 2.09

ELMT-6 79.34 0.054 11.92 1.03 0.027 0.156 0.106 0.119 4.94 0.015 0.37 5.06 41.51 2.15 2.07

Notes: LOI= loss on ignition

166

Table 2.2 Trace (ppm) element compositions of the Herimu Tai granites, fluorites, quartzs and calcites at the Shuitou fluorite deposit.

ELMT-1 ELMT-2 ELMT-3 ELMT-4 ELMT-5 ELMT-6 ST-F08 ST-F09 ST-F10 ST-F11 ST-F12 ST-Q01 ST-Q02 ST-Q03 ST-Q04 ST-Q05 ST-C01 ST-C02 ST-C03 ST-C04 Sample Granite Granite Granite Granite Granite Granite Fluorite Fluorite Fluorite Fluorite Fluorite Quartz Quartz Quartz Quartz Quartz Calcite Calcite Calcite Calcite

La 11.4 2.35 3.84 4.33 2.92 5.97 3.17 0.581 6.75 0.162 0.158 0.765 0.569 0.857 0.122 0.187 7.64 9.99 5.36 15.5

Ce 28.9 16.9 10.8 8.53 9.2 14.5 7.03 1.22 14.7 0.288 0.358 1.6 1.26 1.7 0.224 0.38 14.5 17.6 9.31 32.6

Pr 4.43 0.937 1.5 1.65 1.33 2.48 1.04 0.188 2.15 0.045 0.047 0.223 0.186 0.277 0.03 0.066 1.88 2.21 1.12 4.1

Nd 16.4 4.13 6.01 6.46 5.83 10.7 5.12 0.861 9.64 0.197 0.246 1.06 0.928 1.38 0.166 0.261 8.34 9.79 4.52 18.3

Sm 4.27 1.61 2.15 1.96 2.55 3.47 1.69 0.272 3.52 0.064 0.104 0.262 0.299 0.492 0.056 0.089 2.48 2.13 0.918 3.9

Eu 0.048 0.059 0.013 0.035 0.04 0.043 0.674 0.128 1.57 0.029 0.047 0.04 0.077 0.118 0.01 0.031 1.21 1.17 0.258 0.616

Gd 3.45 1.83 2.68 2.2 3.67 3.2 2.53 0.416 5.04 0.095 0.135 0.262 0.355 0.592 0.057 0.132 3.53 2.72 1.16 4.18

Tb 0.842 0.474 0.716 0.534 0.811 0.704 0.688 0.115 1.45 0.023 0.035 0.046 0.086 0.142 0.016 0.026 0.801 0.459 0.195 0.749

Dy 5.55 4.17 5.59 4 7.37 4.74 4.76 0.799 9.52 0.144 0.233 0.233 0.465 0.946 0.081 0.174 5.06 2.45 1.02 3.74

Ho 1.07 0.77 1.21 0.735 1.2 0.943 0.964 0.149 1.96 0.028 0.046 0.043 0.1 0.197 0.019 0.027 0.949 0.435 0.197 0.63

Er 2.95 2.32 3.17 2.37 3.48 2.72 2.77 0.446 5.58 0.078 0.134 0.111 0.258 0.541 0.049 0.095 2.32 1.05 0.495 1.51

Tm 0.536 0.378 0.524 0.394 0.539 0.444 0.453 0.075 0.871 0.012 0.03 0.014 0.038 0.078 0.008 0.013 0.304 0.13 0.058 0.184

Yb 3.42 2.86 3.33 2.33 3.77 2.96 2.96 0.523 5.15 0.099 0.172 0.085 0.205 0.491 0.06 0.081 1.57 0.697 0.323 0.941

167

Lu 0.436 0.384 0.536 0.391 0.528 0.461 0.367 0.069 0.613 0.011 0.026 0.011 0.028 0.071 0.008 0.01 0.165 0.09 0.037 0.03

Y 26.5 20.3 31.8 21.2 36.9 26.3 30.6 5.38 64.4 1.12 1.54 1.58 4.05 8.15 0.667 1.22 38.6 16.8 8.52 24.4

ΣREE 84 39 42 36 43 53 34 6 69 1 2 5 5 8 1 2 51 51 25 87

LREE/HREE 3.59 1.97 1.37 1.77 1.02 2.30 1.21 1.25 1.27 1.60 1.18 4.91 2.16 1.58 2.04 1.82 2.45 5.34 6.17 6.27

LaN/YbN 2.26 0.56 0.78 1.26 0.53 1.37 0.73 0.75 0.89 1.11 0.62 6.11 1.89 1.19 1.38 1.57 3.31 9.74 11.27 11.19

δEu 0.04 0.10 0.02 0.05 0.04 0.04 0.99 1.16 1.14 1.13 1.21 0.46 0.72 0.67 0.53 0.87 1.25 1.48 0.76 0.46

δCe 0.98 2.76 1.09 0.77 1.13 0.91 0.93 0.89 0.93 0.80 1.00 0.93 0.93 0.84 0.87 0.83 0.90 0.87 0.88 0.97

Rb 343 373 339 316 331 373 0.566 0.666 0.608 0.574 0.1 1.92 2.86 7.1 4.62 4.84 6.52 2.13 50.9 1.01

Ba 89.7 168 79 77.4 84.7 85.7 2.08 4.39 2.16 6.34 1.01 74.4 88.6 114 134 182 15.9 16.2 27.5 3.23

Th 25.4 26.4 29.7 25.4 25.2 32.6 0.054 0.025 0.033 0.081 0.023 0.024 0.1 0.083 0.016 0.022 0.053 0.067 0.07 0.037

U 3.16 4.08 3.68 3.18 3.11 4.8 0.193 0.411 0.088 0.117 0.115 0.088 0.152 0.284 0.019 0.051 0.04 0.025 0.38 0.138

Nb 21.4 19.3 23.6 13.7 20.6 23.1 ------

Ta 1.97 1.86 2.34 2.06 2.4 2.24 ------

Pb 32.3 168 12 27.4 13.9 23.5 0.6 0.528 0.63 2.51 2.56 0.58 1.81 3.7 1.27 3.68 0.914 0.748 2.88 0.88

Sr 20.3 35.4 17.5 19 17.6 15.1 271 274 283 240 287 26.5 48.3 179 89.6 79.6 1125 1780 1207 396

Zr 148 136 114 144 105 117 ------

Hf 6.22 6.56 6.48 6.4 6.34 6.75 ------

168

Ga 18.9 12.9 16.7 16.1 16.1 17.4 0.96 0.18 1.73 0.069 0.063 0.308 1.6 0.644 0.255 0.298 4.92 4.82 7.92 4.81

V 3.68 6.21 2.66 4.54 2.47 1.77 5.8 9.21 10.8 8.02 0.183 0.331 2.18 0.726 1.52 0.631 1.97 1.24 1.5 0.297

Cr 1.98 1.73 1.69 1.86 1.77 1.38 2.16 2.03 1.99 1.97 0.373 0.293 0.35 0.347 0.286 0.395 0.656 0.563 0.907 0.631

Co 101 146 145 126 139 134 2.95 2.42 2.75 2.51 3.95 0.043 0.098 0.975 0.029 0.176 1.02 1.15 1.1 1.15

Ni 6.14 9.92 7.64 7.43 7.16 7.37 42.6 33.3 34.1 34 42.3 0.587 2.11 15.2 0.348 3.01 23.6 33.2 23.7 34.4

Notes: LaN/YbN values are La/Yb ratios normalized to chondrite values after McDonough and Sun, 1995, Eu/Eu*=2*w(Eu)N/[w(Sm)N+w(Gd)N],

Ce/Ce*=2*w(Ce)N/[w(La)N+w(Pr)N].

169

Table 2.3 Zircon U–Pb isotope data for the Herimu Tai granites.

content/ppm Conrrected Isotopic ratios Age(Ma) Spot NO. Th/U Concordance Pb 238U 232Th 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ

ELMT-04-1 34.1 1391 700 0.50 0.0517 0.0037 0.1494 0.0096 0.0215 0.0004 272 165 141.4 8 137.2 2 96%

ELMT-04-3 43.3 1837 891 0.49 0.0468 0.0071 0.1374 0.0208 0.0213 0.0005 35.3 330 130.7 19 135.9 3 96%

ELMT-04-9 67.1 2909 1136 0.39 0.0477 0.0022 0.1399 0.0071 0.0214 0.0003 83.4 107 133.0 6 136.5 2 97%

ELMT-04-12 69.3 2728 1374 0.50 0.0526 0.0042 0.1583 0.0148 0.0216 0.0005 322 181 149.2 13 137.8 3 92%

ELMT-04-20 67.4 2423 1013 0.42 0.0507 0.0054 0.1589 0.0204 0.0213 0.0005 233 220 149.7 18 136.2 3 90%

ELMT-04-25 76.8 2192 1130 0.52 0.0539 0.0037 0.1586 0.0118 0.0213 0.0004 369 156 149.5 10 136.2 3 90%

ELMT-04-29 43.7 1542 689 0.45 0.0458 0.0034 0.1402 0.0114 0.0216 0.0004 1465 79.2 133.2 10 137.5 2 96%

ELMT-04-30 32.9 1218 485 0.40 0.0462 0.0030 0.1412 0.0095 0.0216 0.0005 9.4 144 134.1 8 137.5 3 97%

ELMT-04-31 58.6 2046 741 0.36 0.0500 0.0036 0.1522 0.0113 0.0216 0.0005 195 168 143.8 10 137.6 3 95%

170

Table 2.4 Hf isotope data of zircons of Herimu Tai granites from the Shuitou fluorite deposit.

176 177 176 177 176 177 176 177 Spot NO. t(Ma) Yb/ Hf 2σ Lu/ Hf 2σ Hf/ Hf 2σ Hf/ Hf(t) εHf(0) εHf(t) TDM(Ma) fLu-Hf TDM2(Ma)

ELMT-04-1 136.9 0.083504 0.002387 0.002153 0.000081 0.282778 0.000028 0.282773 0.2 3.0 692 -0.94 994

ELMT-04-3 136.9 0.121953 0.002648 0.003094 0.000099 0.282723 0.000030 0.282715 -1.7 1.0 794 -0.91 1123

ELMT-04-4 136.9 0.095982 0.001490 0.002331 0.000030 0.282739 0.000023 0.282733 -1.2 1.6 754 -0.93 1084

ELMT-04-5 136.9 0.068500 0.000799 0.001701 0.000024 0.282795 0.000023 0.282791 0.8 3.7 660 -0.95 953

ELMT-04-6 136.9 0.137214 0.003741 0.003227 0.000072 0.282833 0.000023 0.282825 2.2 4.9 631 -0.90 877

176 177 176 177 176 177 176 177 λt 176 177 176 177 λt Notes: εHf(0)=(( Hf/ Hf)S/( Hf/ Hf)CHUR-1)×10000, εHf(t)=(( Hf/ Hf)S-( Lu/ Hf)S×(e -1))/(( Hf/ Hf)CHUR-( Lu/ Hf)CHUR×(e -1))-1)×10000 ；

176 177 176 177 176 177 176 177 176 177 176 177 TDM1=1/λ×ln[1+(( Hf/ Hf)S-( Hf/ Hf)DM)/(( Lu/ Hf)S-( Lu/ Hf)DM)]；TDM2=TDM1-(TDM1-t)(fCC-fS)/(fCC-fDM)；fLu/Hf=( Lu/ Hf)S /( Lu/ Hf)CHUR-1；

176 177 176 177 176 177 176 177 ( Lu/ Hf)CHUR=0.0332, ( Hf/ Hf)CHUR=0.282772 (Blichert-Toft and Albarède, 1997), ( Lu/ Hf)DM=0.0384, ( Hf/ Hf)DM=0.28325 (Griffin et al., 2000), 176 177 176 177 176 177 176 177 -11 -1 fCC=[( Lu/ Hf)mean crust/( Lu/ Hf)CHUR]-1, fDM=[( Lu/ Hf)DM/( Lu/ Hf)CHUR]-1, λ=1.867×10 year (Söderlund et al., 2004), t=crystallization age of zircon. The 2σ represents standard deviation.

171

Table 2.5 Sm and Nd isotope compositions of fluorites from the Shuitou deposit.

Sample NO. Sm(ppm) Nd(ppm) 147Sm/144Nd 143Nd/144Nd 2δ

ST-F01 1.7331 3.3908 0.3090 0.512797 0.000014

ST-F02 0.4484 0.7659 0.3540 0.512839 0.000018

ST-F03 0.6915 1.7051 0.2452 0.512742 0.000013

ST-F04 1.6745 4.451 0.2274 0.512728 0.00001

ST-F05 1.7017 4.0652 0.2531 0.512746 0.000022

ST-F06 0.1461 0.2433 0.3630 0.512845 0.000014

ST-F07 0.2346 0.382 0.3712 0.512851 0.000007

172

Table 2.6 Carbon and oxygen isotopic data of calcites from the Shuitou deposit.

13 18 18 Sample NO. Mineral δ CV-PDB, ‰ δ OV-PDB, ‰ δ OV-SMOW, ‰

ST-C01 Calcite -6.3 -30.7 -0.7

ST-C02 Calcite -6.5 -32.2 -2.3

ST-C03 Calcite -7 -32.7 -2.8

ST-C04 Calcite -7.1 -31.2 -1.2 18 6 2 Notes: The δ OH2O values were calculated from Calcite samples based on the isotope fractionation equation of 1000lnα calcite-water = 2.78×10 /T – 3.39 (O'Neil et al., 1969) at the average homogenization temperatures (T) of the associated fluid inclusions.

173

Table 2.7 Microthermometric data for fluid inclusions from the Shuitou fluorite deposit.

Homogenization Density Size (μm) Steam volume (%) Salinity (wt.%) Description Location Numbers Temperature (℃) (g/cm3) Date sources (main range) (main range) (main range) (main range) (Ave.) fluorite: lilac, white; fine grain 45 16~91.3 3~45 the 132~350 0.18~3.71 Zeng et al., fluorite: lilac, white; breccia northern 16 7.7~34.5 5~20 0.87 (160~200) (0.60~1.50) 2013 ore block fluorite: green, lilac; banded 21 16.8~175 5~30 structure fluorite: early–stage; green, 10~30 5~45 148~350 0.18~4.65 0.67~0.95 53 reseda the central (10~20) (10~25) (160~220) (0.8~2.8) (0.88) Zhang 2014 fluorite: late–stage; light brown, ore block 10~25 5~40 126~315 0.18~3.71 0.61~0.94 68 colourless (5~15) (10~20) (140~200) (0.4~1.6) (0.86) 3~50 4~37 120~239 0.18~6.88 0.815~0.916 fluorite: early–stage; green, lilac the 51 (10~20) (10~20) (173.3~189.9) (0.27~2.03) (0.871) southern This study fluorite: late–stage; green, dark 5~40 4~41 132~254 0.18~0.88 0.791~0.923 ore block 62 brown (10~25) (10~15; 30~35) (155~173.2) (0.33~0.68) (0.891)

174

Table 3.1 Trace element compositions (ppm) of fluorite and quartz samples from the Xiaobeigou fluorite deposit

Sample XF1 XF2 XF3 XF4 XF5 XF6 XF7 XF8 XF9 XQ1 XQ2 XQ3

Mineral Fluorite Fluorite Fluorite Fluorite Fluorite Fluorite Fluorite Fluorite Fluorite Quartz Quartz Quartz

La 2.81 2.59 2.93 2.34 1.73 0.39 0.39 0.37 0.51 0.07 0.01 0.02

Ce 6.57 5.74 7.04 5.46 3.48 0.80 0.94 0.82 1.17 0.12 0.02 0.01

Pr 0.96 0.85 1.00 0.77 0.52 0.12 0.15 0.11 0.17 0.02 0.003 0.01

Nd 4.61 3.97 4.46 3.34 2.22 0.59 0.67 0.54 0.81 0.07 0.01 0.03

Sm 1.60 1.45 1.71 1.22 0.80 0.17 0.30 0.18 0.32 0.02 0.01 0.003

Eu 0.68 0.83 1.08 0.84 0.44 0.07 0.10 0.08 0.12 0.01 0.002 0.002

Gd 1.80 1.58 1.85 1.38 0.87 0.23 0.32 0.22 0.37 0.03 0.01 0.003

Tb 0.56 0.43 0.54 0.43 0.27 0.08 0.11 0.07 0.11 0.01 0.002 0.002

Dy 4.29 3.08 4.10 3.17 2.04 0.59 1.02 0.55 0.92 0.04 0.01 0.003

Ho 0.94 0.61 0.75 0.64 0.47 0.12 0.21 0.12 0.19 0.01 0.003 0.002

Er 2.57 1.58 2.02 1.57 1.43 0.38 0.58 0.35 0.51 0.03 0.01 0.002

Tm 0.43 0.25 0.34 0.26 0.27 0.05 0.12 0.07 0.09 0.01 0.002 0.002

Yb 2.16 1.32 1.67 1.31 1.44 0.25 0.60 0.38 0.41 0.03 0.01 0.004

Lu 0.25 0.16 0.19 0.13 0.18 0.03 0.07 0.04 0.05 0.002 0.002 0.002

175

Y 30.60 28.60 26.00 21.20 15.60 4.00 6.15 4.09 7.19 0.41 0.09 0.02

ΣREE 30.21 24.43 29.67 22.86 16.14 3.84 5.59 3.91 5.76 0.45 0.10 0.09

Eu/Eu* 1.21 1.65 1.84 1.96 1.58 1.05 1.00 1.28 1.08 1.25 0.86 2.01

Ce/Ce* 0.97 0.93 0.99 0.98 0.88 0.91 0.93 0.96 0.95 0.82 0.91 0.27

Rb 0.03 0.04 0.03 0.03 0.08 0.05 0.04 0.06 0.04 1.58 0.81 0.85

Ba 0.43 0.11 0.20 0.33 0.67 0.66 0.20 0.30 0.28 4.68 4.23 0.67

Th 0.04 0.06 0.04 0.05 0.04 0.02 0.01 0.004 0.01 0.02 0.002 0.004

U 0.03 0.02 0.01 0.03 0.002 0.023 0.012 0.011 0.006 0.02 0.002 0.002

Nb 0.02 0.03 0.01 0.01 0.02 0.03 0.01 0.01 0.01 0.02 0.002 0.01

Ta 0.01 0.01 0.008 0.007 0.007 0.01 0.006 0.004 0.004 0.004 0.002 0.002

Sr 45.1 23.1 54.2 42.4 40.4 34.3 40.5 37.3 31.9 8.04 9.31 0.44

Zr 0.06 0.09 1.17 0.04 0.10 0.07 0.03 0.02 0.02 0.59 0.07 0.06

Hf 0.02 0.03 0.04 0.04 0.02 0.003 0.01 0.01 0.01 0.01 0.003 0.003

Ga 0.03 0.03 0.03 0.02 0.03 0.04 0.004 0.003 0.01 0.24 0.08 0.07

V 0.10 0.17 0.09 0.12 0.09 0.19 0.11 0.15 0.19 0.18 0.03 0.01

Cr 0.09 0.06 0.06 0.11 0.06 0.08 0.11 0.06 0.07 0.08 0.13 0.10

Co 2.2 2.17 2.08 1.91 1.65 2.44 2.1 2.06 2.29 0.05 0.03 0.01

176

Ni 2.78 2.7 2.77 2.61 2.67 3.56 2.74 2.65 2.75 0.19 0.16 0.08

Notes: Eu/Eu*=2*w(Eu)N/[w(Sm)N+w(Gd)N], Ce/Ce*=2*w(Ce)N/[w(La)N+w(Pr)N], and N = chondrite-normalized concentrations (McDonough and Sun, 1995).

177

Table 3.2 Microthermometric data for primary fluid inclusions in the Xiaobeigou fluorite deposit

℃ Th ( ) Salinity -3 Stage Host mineral Type Number Size (μm) Tm, ice (℃) Density (g·cm ) (main range) (wt% NaCl eqv.)

159.5–260.7 Early stage Quartz L- and V-type 14 5.5–43.8 -0.7 – -0.1 0.18–1.20 0.78–0.92 （200–240） 138.1–266.8 Early stage Fluorite L-type 16 4.6–24.8 -0.5 – -0.1 0.18–0.88 0.77–0.93 （160–200） 132.5–245.8 Late stage Fluorite L-type 50 5.6–48.8 -0.8 – -0.1 0.18–0.88 0.80–0.94 （160–180）

Notes: Tm, ice: final ice melting temperature; Th: homogenization temperature.

178

Table 3.3 Hydrogen and oxygen isotopic compositions for the Xiaobeigou deposit

18 18 Stage Mineral Sample δ OV–SMOW (‰) Tcal (℃) δ OH2O (‰) δD (‰) Early stage Quartz XQ1-2 3.0 220 -7.51 -136.2 Quartz XQ2-2 4.2 220 -6.31 -131.6 Quartz XQ3-2 3.4 220 -7.11 -139.4 Fluorite XF1-2 – – -6.0 -118.0 Fluorite XF2-2 – – -3.6 -116.0 Fluorite XF3-2 – – -5.3 -120.6 Fluorite XF4-2 – – -5.9 -115.5 Fluorite XF5-2 – – -4.9 -121.6 Late stage Fluorite XF6-2 – – -4.2 -119.8 Fluorite XF7-2 – – -2.6 -102.0 Fluorite XF8-2 – – -5.0 -120.8 Fluorite XF9-2 – – -4.5 -121.9

18 6 2 Notes: The δ OH2O values for fluids were balanced with quartz and calculated based on the isotope fractionation equation 1,000lnα quartz–water = 3.38 × 10 /T – 3.40 (Clayton et al., 1972) using the average homogenization temperatures (Tcal) of FIs that were present in the early-stage quartz

179