Research Article Petrogenesis and Geodynamic Implications of a Newly Discovered Basanite Dike in Zaolin, Jingdezhen City, South China

GeoScienceWorld Lithosphere Volume 2021, Article ID 9732167, 22 pages https://doi.org/10.2113/2021/9732167

1 1 1 2 3 Xiaofei Pan , Yufeng Ren , Zengqian Hou, Yongpeng Ouyang, Xuejing Gong, 1 1 Qiuyun Li, and Yanshen Yang 1Institute of Geology, Chinese Academy of Geological Sciences, No. 26, Baiwanzhuang Road, Beijing 100037, China 2912 Geological Team, Bureau of Geology and Mineral Resources of Jiangxi Province, Yingtan 335001, China 3China Deep Exploration Center—SinoProbe Center, Chinese Academy of Geological Sciences, Beijing 100037, China

Correspondence should be addressed to Xiaofei Pan; [email protected] and Yufeng Ren; [email protected]

Received 25 May 2020; Accepted 20 January 2021; Published 3 March 2021

Academic Editor: Christoph Hauzenberger

A recently discovered basanite dike in the Zaolin area of Jingdezhen, South China, contains mantle xenocrysts such as kink-banded – olivines, olivines + orthopyroxenes assemblage, and chromites. In addition, polymorphic carbonates of the MgCO3 FeCO3 series occur as augens, either independently or interspersed with diopside and spinel in the matrix. The rock is characterized by high Cr and Ni contents, high whole-rock Mg# values (0.66–0.72), and high Ca/Al (0.72–1.03) and TFeO/MgO (1.1–1.3) ratios and is alkali- rich with Na2O K2O. The trace-element partition patterns are similar to those of other basanites in eastern China as well as ocean island basalts. Whole-rock geochemical analyses show depleted Sr and Nd isotopic compositions ( : – : εð Þ : – : , > ). These data indicate that the rock has experienced negligible crustal contamination,86 87 should be – derived from asthenospheric mantle, or mixed by the MORB with EMI/EMII mantle and have been carbonated.Sr/ TheSr calculated = 0 70358 T – 0P 703853conditionsNd of the = melt2 52 in 6equilibrium73 with xeno-olivine are 1160 1320 C at the mantle depth. The high Cr# values of the spinel – xenocrysts indicate that the lithospheric mantle under the Jingdezhen area° was probably relict Proterozoic mantle. The Ar Ar plateau age and the isochron and inverse isochron ages for the matrix of the basanite are all 44 Ma. The basanite, as well as other alkaline basalt or lamprophyre dikes in southeastern China, formed in a rifting regime during the Eocene.

1. Introduction evolved from an island-arc setting during the late Mesozoic ([1, 3–16]). Compared with the Miocene to Pleistocene alka- Cenozoic alkaline basalt provinces occur in every continent line basalts, the Paleogene basalts (65–23.5 Ma) are less volu- and are commonly associated with active lithospheric exten- minous and have received less attention [3]. Despite the sion in localized continental rifts or over broader continental smaller volumes of volcanic products, the Paleogene is still regions ([1]). Large volumes of Cenozoic alkaline basalts are considered to be an important stage of active volcanism also widespread in the eastern Asian continental margin based on basin drilling data and vein properties ([8, 9, 17, (Figure 1(a)). These basalts outcrop along coastal areas and 18]). Cong et al. [8] proposed that during the Oligocene, east- adjacent oﬀshore shelf regions from north of Heilongjiang ern China entered a stage of continental-margin rifting based province to south of Hainan Island, as well as in the South on the occurrence of Paleocene tholeiitic basalts (58.7– China Sea along the eastern margin of China, together con- 59.7 Ma) and Oligocene alkaline basalts (22.7–28.8 Ma) in stituting the eastern China volcanic belt ([2]; Figure 1(b)). the Subei Basin. They were erupted mainly during the Miocene and Pleisto- Paleogene (especially Eocene) alkaline basalts have cene (20.7-0.38 Ma, [3]). The petrogenesis and tectonic rarely been reported in Jiangxi Province and include 41– implications of these rocks have been described previously 40 Ma basalt dikes that crop out in Guangfeng City, south- in studies that the NNE-trending belt of Cenozoic mantle- east of Jingdezhen ([19]; Figure 1(a)), and a 44 Ma lampro- xenolith-bearing alkaline basalts represents a rift setting that phyre dike in the Anyuan area south of Jingdezhen ([20];

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 2 LITHOSPHERE

110 120 130 110 120 130

(a) (b) Russia

Wudalianchi

Heilongjiang

Xin-Mengblock Jilin Tan-Lu fault 40 Changbaishan Inner Mongolia Mongolia 110Kangdian 120 Liaoning Hannuoba Beijing Datong Korea Shandong Hebei North Chicna Shănxi plate Ningxia Yellow s ea Shandong Yellow river

Subei Shănxi Henan 30 16.3Ma Jiangsu Tan-Lu fault Gansu Tashan Nűshan 0.55-0.72Ma Fangshan 9,1-9,4Ma Shanghai Sichuan Anhui Fig.2 East China sea Hubei Zaolin Chongqing Longyou (Pliocent-Pleistocene) Zhejiang Yangtze river Yangtze 40-41Ma Xilong(Pliocent-Pleistocene) plate Mingxi Hunan Jiangxi 1.4-4.9Ma Fujian Taipei Guizhou Jiangshao-Pingxiang fault -4.9Ma Taipei Niutoushan 16.7-17.9Ma Cathaysia plate Guangdong Kunming Guangxi Dapu-Zhenghe-2Ma fault Guangzhou 20 Leizhou South China sea peninsular -1Ma 0 150 300 km Hainan Hainan island

110 120 Cenozoic volcanics Jiangxi province Guangfeng basalt Major faults Anyuan lamprophyre Plate boundary

Figure 1: Simpliﬁed Cenozoic volcanic geology and tectonic framework of eastern China (modiﬁed after E and [9, 39]).

Figure 1(a)). Recently, a basanite dike was discovered in areas and adjacent oﬀshore shelf regions and extends over Permian carbonate rocks in the Zaolin area of Jingdezhen 2000 km from north to south along the eastern edge of the City, Jiangxi Province (Figure 1(a)), at the eastern margin Asian continent (Figure 1(a)). Tectonically, this belt occupies of the Yangtze Block (Figure 2). However, the geochronol- (from north to south) the Xing’anmeng Block and the eastern ogy, source, petrogenesis, and geodynamic setting of this parts of the North China, Yangtze, and Cathaysia Block dike are unknown. This paper reports Ar–Ar ages and min- (Figure 1(b)). These blocks and plates have generally been eralogical, petrologic, geochemical, and Sr and Nd isotope considered an assembly of exotic continental terranes that data for this dike to ascertain its origin and genesis and pro- broke away from Gondwanaland, with their amalgamation vide insights into the composition and physical behavior of having been largely completed during the early Mesozoic the subcontinental lithospheric mantle of eastern China. [2, 7, 21, 22]. Continental extension and upper mantle con- vection in eastern China, induced by subduction of the 2. Geological Setting Paciﬁc plate underneath the Asian continent, have been widely accepted as a possible mechanism for the genesis of The eastern China volcanic belt is composed of widespread the Cenozoic intraplate basaltic volcanism ([23] and refer- Cenozoic basaltic rocks that are distributed along coastal ences therein). Besides, alternative mechanisms including

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 3

117°00ʹE 117°30ʹE 29°20ʹN (d) 05km

Jingdezhen

Zhuxi

Zhengzhushan

Yangcaojian

Yuexing Taqian Henglu Zaolin

29°20ʹN 117°30ʹE 117°30ʹE Quaternay clay, sand and sandy gravel layer Granodiorite porphyry Cretaceous red sandstone siltstone Granite porphy dyke Jurrasic lacustrine facies sandy conglormerate and sandstone Pyroxenite Triassic siltstone Stratigraphic boundary Perimian limestone-mingled clastic rocks Stratigraphic unconformity surface Carboniferous system limestone Faults Neoproterozoic Shuangqiashan group

Figure 2: Geological map of the Zaolin area, Jingdezhen, Jiangxi Province (modiﬁed after [37, 45]).

upwelling of a mantle plume [24–28] or eastward astheno- was controlled by the Mesozoic structural framework [3]. spheric flow from beneath western China to eastern China The recently discovered basanite dike studied here is located [29, 30] also have been proposed. in a quarry in Zaolin (29 5′39.67″N, 117 10′23.26″E), about South China, as a member of this volcanic belt, is com- 30 km south of Jingdezhen° City in South° China (Figure 2). posed of the Yangtze Block in the west and the Cathaysia Block (including Taiwan) in the east. Since the Indosinian, 3. Lithology and Petrography the eastern part of South China has become an active continental margin as a result of the collision between the paleo- Neoproterozoic and minor Paleozoic and Mesozoic strata Pacific and Eurasian plates after the Neoproterozoic amal- strike NE–SW, corresponding to the NE-oriented faults in gamation of the North China and Yangtze Blocks. Subse- the Zaolin area (Figure 2). The Zaolin basanite dike outcrops quently, long-term crustal deformation and lithospheric about 25–30 m long and 0.8–4.5 m wide and intrudes Perm- thinning started, a series of NE-trending faults and graben ian carbon-bearing limestones (Figure 3(a)). A shear fault basins developed from north to south in the eastern part of cut off the basanite dike body into two sections with a displa- South China ([9, 17, 31–34]), and sediments were deposited cing distance of about 2 meters (Figure 3(a)). The Permian during Paleozoic to early Mesozoic period. Red-bed and flu- limestones are also intruded by Late Jurassic–Early Creta- vial–lacustrine facies are well developed in the graben basins ceous granitoid porphyries that host the giant Zhuxi ([35]; Figure 1). During the early Cenozoic, the eastern part W–(Cu) copper ore deposit [37]. of South China entered a stage of continental rifting, with fre- The basanite rock is very fresh except for minor fade quent volcanic eruptions and magmatic intrusions that are alteration (indicated by a grayish-white color) and crack thought to have been related to paleo-Pacific plate subduc- deformation within a narrow contact zone (1–5 cm) with tion and are distributed in basins or along NE- and NNE- the Permian strata (Figures 3(b)–3(e)). The basanite is gray- trending faults ([3, 9, 17, 36]). Cenozoic alkaline basaltic ish dark, massive, and porphyritic (Figures 3(c)–3(e)). Phe- rocks are exposed in Jiangsu, Zhejiang, and Fujian provinces nocrysts (0.05–0.20 mm) occupy 5–10 vol% of the rock as well as near and southeast of the Dapu–Zhenghe Fault mass and are mainly olivine with minor clinopyroxene, car- (e.g., Ming Xi, Longyou, Xilong, and Niutoushan). The basal- bonate, and spinel (Figure 4). The matrix consists predomi- tic magma was derived from the deep mantle, and its ascent nantly of microliths or microcrystals of clinopyroxene, with

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 4 LITHOSPHERE

(a) (b)

Basanite dike Fault

(c)

500 �m (d) (e)

Cpx

O1 Cpx

100 �m

Figure 3: Field photographs and photomicrographs of the Zaolin basanite: (a, b) photographs showing the basanite (dotted white line) within Permian carbonate strata and displaced by a fault (solid white line); (c) photograph of a hand specimen (ZL-36); (d) photomicrograph of the Zaolin basanite (cross-polarized light) showing porphyritic texture with olivine phenocrysts; (e) clinopyroxene phenocrysts (plane-polarized light). ol: olivine; Cpx: clinopyroxene.

rim

sp Car

ol ol sp Car cpx

� 50 m 200 �m

(a) (b)

rim cpx ol opx sp ol

200 �m 200 �m (c) (d)

Figure 4: Photomicrographs of basanite under an optical microscope. (a) Augen carbonates (transmitted light). The cpx occurs as columnar crystals in the matrix. Spinel occurs as inclusions in carbonate and between carbonate grains. (b) Kink-banded olivine xenocryst with a clear margin (cross-polarized light). Other phenocrysts are olivine that crystallized from magma. (c) Ol + opx xenocrysts (reﬂected light). (d) Brown spinel xenocryst and tiny dark spinels (transmitted light). ol: olivine; opx: orthopyroxene; cpx: clinopyroxene; sp: spinel; Car: carbonate; rim: rim of olivine or spinel.

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 5

lesser amounts of spinel, olivine, and apatite, as well as glass- an accelerating voltage of 15 kV, a beam current of 20 nA, like nepheline and sanidine (Figure 5). In contrast to basa- and collection time of 10 s. nites found elsewhere [38, 39], the Zaolin basanite does not Two batches of five and seven samples were analyzed for contain plagioclase. whole-rock major- and trace-element compositions at the Magma-crystallized olivine in the basanite is predomi- National Research Center for Geo-analysis of Beijing, CAGS, nantly euhedral or subhedral, with most grains being fresh, Beijing, China. Major elements were analyzed by X-ray fluo- although a few phenocrysts are serpentinized or carbonized rescence spectrometry (XRF) based on certified standards (Figures 3(c)–3(d) and 4(a)–4(c)). Some olivine grains have (GSR-1 and GSR-3) and duplicate analyses, with the analyti- well-developed cleavages and are fractured and tabular in cal uncertainties being 5%. Ferric and ferrous iron measure- shape (Figure 4(b)). Some of the olivines contain inclusions ments were determined by wet chemical analyses (titration). of spinel + clinopyroxene + sanidine + nepheline, identical Trace elements were determined< using solution inductively to the assemblage of the groundmass (Figure 5(a)). Olivines coupled–plasma mass spectrometry (ICP–MS). in the matrix are anhedral, show minor alteration, and locally Rb–Sr and Sm–Nd isotopes were analyzed by thermal occur in aggregates (Figures 5(a) and 5(b)). Clinopyroxene ionization mass spectrometry (TIMS, Finnigan MAT-262) phenocrysts are prismatic and euhedral with well-developed at the Laboratory for Radiogenic Isotope Geochemistry, zoning (Figure 5(b)), with some occurring as aggregates. In University of Science and Technology of China, Hefei, China. contrast to olivine, which dominantly occurs as phenocrysts, 87Sr/86Sr ratios were normalized to : , and 143 144 clinopyroxene occurs mainly as tiny laths in the groundmass Nd/ Nd ratios were normalized86 to88 (Figures 4(a), 4(d), and 5). Spinel is opaque, euhedral, or : 87 86 , to correct for isotopic fractionation.Sr/ Sr146 =Sr/ 0 1194Sr144 ratios anhedral and occurs as fine grains scattered in the ground- were adjusted to NBS-987 Sr : , and 143 144 Nd/ Nd = mass (Figures 4 and 5). Carbonate, in fact being polycrystal- 0 7219Nd/ Nd ratios were adjusted to Shin Eston Jndi-1 Nd : line, occurs mainly as augen-like phenocrysts (Figures 4(a) . The uncertaintiesstandard for = 0 concentration710250 and 5(c)–5(f)) or anhedral matrix grains among silicate min- analyses by isotopic dilution are 2% for Rb, 0.5%–1.0% erals (Figures 5(d), 5(e), and 5(g)). Augen carbonates contain standardfor Sr, and = 0.5% 0 512115 for Sm and Nd, depending on concentration inclusions of spinel (Figures 4(a) and 5(c)) and are locally levels. The overall uncertainty for± Rb/Sr is ±2% and for intergrown with clinopyroxene (Figure 5(c)), and the silicate Sm/Nd is 0.2%–0.5%. The procedural blanks were 100 pg fi matrix lacks quenching rim and ssures where in contact for Rb and Sr and 50 pg for Sm and Nd. ± with the carbonates. We therefore attribute the carbonates Matrix± minerals in the samples were obtained after care- to silicate–carbonate-liquid immiscibility products (augen fully removing the olivine and pyroxene phenocrysts and phenocrysts) or coprecipitated products (in the matrix) xenocrysts, as well as the felsic xenoliths to increase the K within the magma, but not to capture foreign inclusions or concentration. The matrix minerals were then irradiated in veins. Apatite occurs in the groundmass as very tiny needles a quartz vial in a nuclear reactor at the Chinese Institute of (Figures 5(a) and 5(g)). Atomic Energy, Beijing, China. 40Ar/39Ar age determina- Mantle-derived xenocrysts occur in the basanite as 0.1– tions were performed at the Ar–Ar laboratory at CAGS. 2 mm in size and consist of olivine, olivine + spinel, or olivine The decay constant for 40K used in the calculations was − + orthopyroxene assemblages (Figures 4(b)–4(d)). This type : − yr 1 [40]. 40Ar/39Ar spectra were constructed of olivine shows clear cores and rims, is anhedral, and is the using Isoplot10 [41]. largest mineral in the rock. Kink bands are observed in the 5 543 × 10 olivine xenocrysts (Figure 4(b)). The spinel xenocrysts 5. Results (0.05–0.50 mm) are euhedral or anhedral, mostly brown in color, and dark along their rims and fractures (Figures 4(d), 5.1. Mineral Chemistry. Representative microprobe data for 5(f), and 5(g)). minerals in the Zaolin basanite are listed in Supplementary Felsic enclaves are locally observed and are inferred to Data Tables 1–6. have been captured from wall rocks along the volcanic Olivine xenocrysts have uniform compositions and the conduit through which the dike-forming magma traveled. highest MgO contents of the studied minerals, with Fo values of 89.5–90.7 in cores and 79.6–85.2 in rims (Figure 4(b); Supplementary Data Table 1). In the cores, NiO and 4. Analytical Methods CaO contents are 0.3 wt% and 0.06 wt%, respectively. Orthopyroxene xenocrysts are interspersed between olivine 49 thin-sections were prepared for petrographic analyses and mineral xenocrysts> ( ) (Figure< 4(c)) and have a fi mineral identi cation and imaging of the components, tex- composition of En89Wo1Fs10 and an Al2O3 content of ture, and structure of the basanite samples using a Leica 3.74 wt% (SupplementaryFo = Data 90 Table 2). Spinel xenocrysts 4500P microscope and an energy dispersive spectroscope are anhedral or euhedral, with clearly defined cores and (EDS) (JEOL JSM–5610LV, focusing distance of 18 mm and rims (Figures 4(d) and 5(f)–5(h)). Of the studied minerals, accelerating voltage of 20 kV) at the Institute of Geology, these spinels have the lowest contents of TiO2 ( 1 wt%), the – Chinese Academy of Geological Sciences (IG CAGS), Bei- highest contents of MgO (18 wt%) and Cr2O3 (43 wt%), and – ð Þ jing, China. Representative minerals were selected and ana- yield Cr# values of 25 65 ( < ) and lyzed using an electron probe microanalyzer (JEOL JXA- Mg# values of 44–69 (( ð Þ) – μ 8100) at IG CAGS, with a focused beam diameter of 5 m, (Supplementary Data Table 3).Cr# The = atom very Cr/ lowCr TiO +2+2 Al(mostly3+ Mg# = atom Mg/ Mg + Fe +Fe

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 6 LITHOSPHERE

ol ne ne ap cpx sa ne ne ne ol ne ol cpx sa cpx ap cpx ne

ne ap

ol cpx sa sa

JEOL COMP 15.0kV ×230 100�m WD11mm JEOL COMP 15.0kV ×270 100�m WD11mm (a) (b)

cpx Car Car cpx

ol Car ol Car

Car Car

Car

JEOL COMP 15.0kV ×130 100�m WD11mm JEOL COMP 15.0kV ×270 100�m WD11mm (c) (d)

ol ol

cpx Car

ol Car sp

Car

JEOL COMP 15.0kV ×70 100�m WD11mm JEOL COMP 15.0kV ×140 100�m WD11mm (e) (f)

ne ap Car sp sp ne ol

ne cpx

Car cpx Car

× � JEOL COMP 15.0kV ×250 100�m WD11mm JEOL COMP 15.0kV 110 100 m WD11mm (g) (h)

Figure 5: Back-scattered electron images of the Zaolin basanite. (a) Inclusions of cpx, sp, and ne in olivine, similar to the mineral assemblage in the matrix. Needle-like apatites occur in the matrix. (b) Zoned clinopyroxene phenocryst. In the matrix, sanidine and nepheline appear as light and dark, respectively, distributed between columnar clinopyroxene grains. (c) Augen of siderite interspersed with cpx and sp. (d) Augen of carbonate showing distinct phase separation, with the dark parts of the carbonate being Mg-rich magnesite and light parts being Fe-rich siderite. (e) Heterogeneous carbonate with MgO and FeO contents of 50%. (f) Spinel xenocryst eroded by magma, showing a Ti- and Fe-rich rim and fractures, whereas its inner part is primarily chromite, rich in Mg and Cr. (g) Eroded spinel with several compositional zones. Near the spinel is siderite coexisting with ne and cpx. (h) Eroded spinel,~ rich in Ti and Fe, or Ti-magnesite. The tiny (light-colored) minerals scattered in the matrix of images (a–h) are Cr–Ti–Mg–Fe spinel. ol: olivine; cpx: clinopyroxene; sp: spinel; Car: carbonate; ap: apatite; ne: nepheline; sa: sanidine.

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 7

0.3 wt%) contents suggest that the spinel xenocrysts are Wo residual chromite [42]. The rims are rich in TiO2 and FeO, similar< to the spinels in the matrix, and show Cr# values of 38–57 and Mg# values of 2–17, suggesting the rims are a product of reaction between melt and spinel xenocrysts. Strong erosion by the magma converted the high-Cr spinel to Ti-rich chromite and Ti-magnetite (Figures 5(f) and 5(g)). The relationship between spinel Cr# and olivine Fo indicates the xenocrysts were derived from a mantle source [38, 42, 43]. In addition, on the basis of the high Fo, En, Diopside and Mg# values of olivine and pyroxene, the xenocrysts are analogous to spinel lherzolite and harzburgite inclusions in Augite Cenozoic alkaline basalts of eastern China ([5, 9, 17, 20, 44]) and are from the lithospheric mantle. Magma-crystallized minerals including olivine, clinopyr- Pigeonite oxene, spinel, carbonate, sanidine, nepheline, and apatite have been measured. The magma-crystallize dolivine with – Enstatite Ferrosilite Fo end-member composition has Fo values of 79 85 (mostly En Fs 83–85), differing from olivine xenocryst cores but similar to olivine xenocryst rims (Supplementary Data Table 1). Figure 6: Classification of pyroxene [125] into diopside, augite, These olivines have higher CaO (0.2–0.5 wt%) and lower pigeonite, enstatite, and ferrosilite. The data point in the enstatite NiO (0.1–0.2 wt%) contents than the olivine xenocrysts. field is of opx interspersed with olivine xenocrysts. The circle near Near felsic inclusions, the Fo content of the magmatic the center, on the diopside–augite boundary, represents the olivine drops markedly to 45–53 (Supplementary Data compositions of the cpx near felsic enclaves. Table 1, analysis points 93 and 94), suggesting that Fe–Mg partitioning between the melt and minerals (olivine and that spinel in the matrix contains Cr, Ti, Mg, Fe, and Al clinopyroxene) was affected by temperature and pressure together in single crystals and that the basanite contains when cold foreign enclaves were introduced. mantle-derived xenoliths. The clinopyroxenes plot in the diopside domain in a The carbonates are polyphasic, occur mainly as solid fi pyroxene classi cation diagram (Figure 6). These clinopyr- solutions of FeCO3 and MgCO3 with minor CaCO3 end- – oxenes commonly contain TiO2 and show compositional members (Figures 5(c) 5(f)), and show clear compositional zoning (Supplementary Data Table 2). Clinopyroxenes in heterogeneities (Supplementary Data Table 4). The darker the matrix are homogenous and rich in Ti and Al, having parts of these carbonates in BSE images (Figures 5(d) and the highest TiO2 (7 wt%) and Al2O3 (13 wt%) contents of 5(e)) correspond to magnesite with compositions of Cc1– the studied clinopyroxenes. Diopside is mainly CaTiAl2O6, 7Sid18–41Mag80–52, and the lighter parts correspond to CaAl2SiO6, NaAlSi2O6, CaFe2SiO6, and NaFeSi2O6. If only siderite with compositions of Cc1–19Sid52–82Mag14–47. the Wo, En, and Fs end-members are considered, the Carbonate in the groundmass coexists with alkaline diopside has compositions of En38–32Wo53–48Fs16–9, similar feldspars and diopside and has a sideritic composition to those of Cenozoic basanites in other areas such as (Figures 5(d) and 5(g)). Locally, carbonate with MgCO3 Nushan, Tashan and Fangshan (Subei; [5, 14, 45]), Mt. and FeCO3 contents of 50% occurs adjacent to carbonate Vulture volcanic complex (Italy; [46]), and Izu–Bonin augens or is distributed along the margins of, and fractures volcanic arc (Japan; [38]). within, olivine. Ionov et~ al. [49] considered that magnesite – The magmatic spinel shows clear compositional hetero- (MgCO3 FeCO3) from carbonate-bearing spinel lherzolite geneity even in tiny matrix grains. Spinel centers are rich in inclusions in the Spitsbergen basalt was a secondary, – – Cr2O3 and MgO and poor in TiO2 and FeO relative to the posteruption product. The MgCO3 FeCO3 system at 600 – – edges, with Cr# values of 38 60 and Mg# values of 1 40. 800 C and 15 kbar is completely solid solution, and CaCO3 The high TiO2 and FeO contents of the edges are similar has° limited solubility in this system even at 800 C [50]. – to those measured for the rims and fractured parts of spinel When the temperature drops below 300 C, MgCO3° FeCO3 xenocrysts (Supplementary Data Table 3). The compositions solid solution might separate. These characteristics° of the – ff of the magmatic spinels are similar to those of spinels found MgCO3 FeCO3 series carbonate within the basalt di er in kimberlite [47] and leucite basanite (7.28 wt% TiO2, markedly from those of olivine basalt in the CaCO3 [46, – – 6.40 wt% Al2O3, 28.13 wt% Cr2O3, 50.46 wt% FeO, and 51], CaCO3 CaMg(CO3)2 [52], CaCO3 FeCO3 [53], and – 5.27 wt% MgO; [48]) in that Cr2O3, MgO, TiO2,Al2O3, FeCO3 CaMg(CO3)2 series [54], which might be associated and FeO occur together in single crystals, in contrast to with a melt rich in CaO to which a carbonate component basanite in the Izu–Bonin arc [38], which contains Ti-free was subsequently added. chromite or evolved basanite with Ti-magnetite [46]. We The sanidine and nepheline in the basanite are closely infer that the spinels in the matrix of the studied Zaolin intergrown and very fine ( 20 μm in size), as confirmed by basanite were inherited from lithospheric spinels that were electric microprobe analyses (Figures 5(a), 5(b), and 5(g)). trapped and altered by Ti-rich alkaline silicate melts, given These two minerals appear~ only as intergranular phases in

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 8 LITHOSPHERE

Table 1: Major (wt.%) and trace element (ppm) compositions of the Zaolin basanite.

Sample no. ZX14-36 ZX14-37 ZX14-38 ZX14-39 ZX14-40 zl-23 zl-24 zl-25 zl-26 zl-27 zl-28 zl-29

SiO2 41.31 43.02 40.09 44.30 42.41 42.06 41.40 41.47 42.66 43.17 42.26 42.09

TiO2 2.32 2.32 2.22 2.29 2.36 2.45 2.42 2.40 2.42 2.36 2.39 2.43

Al2O3 11.61 11.33 10.91 11.12 11.55 11.60 11.57 11.48 11.55 11.59 11.48 11.59

Fe2O3 2.05 3.54 3.94 3.83 3.39 4.13 4.65 4.40 5.57 4.38 4.21 3.75 FeO 10.01 8.44 8.02 8.06 8.87 8.24 7.67 7.74 7.02 7.85 8.10 8.53 MnO 0.19 0.18 0.17 0.18 0.18 0.18 0.19 0.18 0.18 0.17 0.18 0.18 MgO 10.69 10.53 9.02 10.22 10.80 11.45 11.13 10.21 11.49 9.69 10.63 11.36 CaO 9.43 9.54 12.35 9.10 9.23 9.22 9.55 9.82 9.24 9.98 10.29 9.40

Na2O 4.05 4.10 3.33 4.19 3.97 4.54 4.75 3.92 3.94 3.67 3.88 4.33

K2O 2.28 1.74 2.06 1.62 2.25 2.18 1.10 2.04 2.47 1.30 1.21 2.05

P2O5 1.19 1.17 1.12 1.16 1.18 1.22 1.23 1.21 1.20 1.19 1.20 1.21

CO2 2.23 1.55 3.80 1.98 1.50 0.17 0.94 2.14 0.17 0.69 0.34 0.26 + H2O 2.24 2.52 3.12 1.84 1.94 2.65 2.78 2.40 2.30 2.99 3.30 2.77 LOI 3.31 3.14 5.46 2.66 2.20 1.98 3.40 3.82 1.90 3.45 3.47 2.16 Mg# 0.66 0.69 0.67 0.69 0.69 0.71 0.72 0.70 0.75 0.69 0.70 0.71 TFeO/MgO 1.15 1.17 1.37 1.20 1.17 1.12 1.15 1.23 1.14 1.31 1.20 1.11 Ca/Al 0.74 0.77 1.03 0.74 0.73 0.72 0.75 0.78 0.73 0.78 0.81 0.74 La 66.4 65.8 62.4 64.3 65.9 70.5 68.8 72.6 75.0 69.6 74.4 74.0 Ce 127 127 120 126 130 147 130 150 148 130 141 151 Pr 13.7 13.5 12.8 13.6 13.6 15.5 14.8 15.7 15.9 15.4 15.9 16.7 Nd 50.3 50.7 48.3 50.4 50.7 56.9 64.2 48.2 52.6 62.5 70.0 61.6 Sm 10.4 10.4 9.71 10.2 10.4 11.4 11.0 11.2 10.8 10.3 11.6 11.6 Eu 3.11 3.10 2.94 3.03 3.20 3.51 3.21 3.40 3.46 3.33 3.73 3.54 Gd 9.08 8.84 8.05 8.53 8.76 9.40 7.96 8.46 8.90 8.36 9.04 8.80 Tb 1.19 1.21 1.10 1.17 1.19 1.32 1.13 1.23 1.19 1.21 1.18 1.21 Dy 6.01 6.18 5.82 5.89 6.05 5.84 5.24 5.67 5.62 5.21 5.79 5.76 Ho 0.91 0.91 0.85 0.89 0.90 0.94 0.84 0.88 0.90 0.86 0.97 0.90 Er 2.35 2.44 2.33 2.43 2.43 2.23 1.85 2.14 2.19 1.94 2.19 2.12 Tm 0.24 0.24 0.23 0.24 0.24 0.24 0.24 0.26 0.25 0.23 0.25 0.24 Yb 1.36 1.42 1.33 1.33 1.43 1.47 1.28 1.37 1.41 1.31 1.49 1.39 Lu 0.19 0.20 0.18 0.19 0.18 0.20 0.18 0.18 0.18 0.18 0.18 0.19 Li 11.9 10.2 10.3 9.2 12.6 8.3 6.5 10.8 8.5 11.6 11.0 9.3 Be 4.04 3.86 3.69 3.75 3.86 3.87 3.49 3.94 3.64 3.53 3.56 4.06 Sc 14.1 14.5 16.1 15.8 14.3 16.7 15.4 15.3 15.6 15.1 15.3 16.7 V 222 224 212 211 227 190 188 196 178 184 177 195 Cr 367 380 345 354 389 360 307 341 341 337 321 373 Co 57.9 56.6 57.4 55.5 58.2 59.8 56.2 58.6 55.0 56.3 55.4 61.8 Ni 284 285 287 268 299 271 249 261 244 245 248 273 Cu 48.2 47.9 46.3 45.8 48.5 57.8 73.9 61.6 61.5 48.5 62.5 61.4 Zn 129 129 126 129 135 226 256 153 173 132 161 146 Ga 24.4 24.1 23.6 23.7 24.7 25.4 23.5 23.3 22.9 24.7 23.8 25.2 Rb 28.8 35.1 32.2 39.2 29.6 24.0 32.1 40.4 27.5 71.8 69.3 35.2 Sr 1466 1409 1382 1386 1453 1322 1266 1255 1219 1217 1183 1393 Y 23.8 23.9 23.2 23.3 23.9 25.9 25.7 25.4 25.3 24.6 24.2 26.6 Zr 305 295 291 293 307 310 299 290 280 306 294 322 Nb 108 102 99.8 100 106 92.1 90.5 89.8 87.7 86.4 86.8 93.6 Cs 2.30 8.12 16.70 2.65 5.07 2.00 1.47 9.74 6.34 82.00 37.00 3.36 Ba 406 416 400 393 413 408 352 437 419 415 618 454

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 9

Table 1: Continued.

Sample no. ZX14-36 ZX14-37 ZX14-38 ZX14-39 ZX14-40 zl-23 zl-24 zl-25 zl-26 zl-27 zl-28 zl-29 Hf 6.63 6.72 6.64 6.82 6.70 7.70 6.86 7.35 7.38 7.08 7.27 7.50 Ta 6.02 5.71 5.44 5.78 5.77 6.08 5.42 5.78 5.60 5.55 5.82 5.91 W 1.00 1.04 3.26 1.29 0.94 4.78 31.60 7.30 3.30 2.62 2.97 3.05 Pb 5.83 5.78 5.59 5.77 6.16 Th 9.64 9.52 9.25 9.62 9.54 9.14 8.34 8.77 8.90 8.86 9.34 9.26 U 2.81 2.80 2.65 2.73 2.80 2.77 2.47 2.77 2.61 2.63 2.66 2.80 La/Yb 48.8 46.3 46.9 48.3 46.1 48.0 53.8 53.0 53.2 53.1 49.9 53.2 Zr/Hf 46.0 43.9 43.8 43.0 45.8 40.3 43.6 39.5 37.9 43.2 40.4 42.9 Gd/Yb 6.68 6.23 6.05 6.41 6.13 6.39 6.22 6.18 6.31 6.38 6.07 6.33 Sm/Yb 7.65 7.32 7.30 7.67 7.27 7.76 8.59 8.18 7.66 7.86 7.79 8.35 LREE 271 271 256 268 274 305 292 301 306 291 317 318 HREE 21.3 21.4 19.9 20.7 21.2 21.6 18.7 20.2 20.6 19.3 21.1 20.6 Nb/La 1.63 1.55 1.60 1.56 1.61 1.31 1.32 1.24 1.17 1.24 1.17 1.26 La/Ta 11.0 11.5 11.5 11.1 11.4 11.6 12.7 12.6 13.4 12.5 12.8 12.5 La/Nb 0.61 0.65 0.63 0.64 0.62 0.77 0.76 0.81 0.86 0.81 0.86 0.79 Zr/Nb 2.82 2.89 2.92 2.93 2.90 3.37 3.30 3.23 3.19 3.54 3.39 3.44 Zr/Y 12.8 12.3 12.5 12.6 12.8 12.0 11.6 11.4 11.1 12.4 12.1 12.1 Nb/Y 4.54 4.27 4.30 4.29 4.44 3.56 3.52 3.54 3.47 3.51 3.59 3.52 Ti/Y 584 582 573 589 592 567 564 566 573 575 592 547

TiN/EuN 0.58 0.58 0.58 0.56 0.57 0.64 0.70 0.66 0.63 0.65 0.56 0.65

LaN/ZrN 3.55 3.64 3.50 3.58 3.51 3.71 3.76 4.09 4.37 3.71 4.13 3.75

HfN/YN 4.10 4.14 4.22 4.31 4.13 4.38 3.93 4.26 4.30 4.24 4.42 4.15 Zr/Ta 50.7 51.7 53.5 50.7 53.2 51.0 55.2 50.2 50.0 55.1 50.5 54.5 Nb/Hf 16.3 15.2 15.0 14.7 15.8 12.0 13.2 12.2 11.9 12.2 11.9 12.5

the matrix. In BSE images, the relatively light-colored min- Apatite, confirmed by EDS analysis (Figures 5(a), 5(b), fi erals correspond to sanidine, with compositions of Or84– and 5(g)), occurs as very ne needles in the matrix. This apa- 55Ab41–11An7–0 (Supplementary Data Tables 5 and 6). The tite might contribute to the whole-rock phosphorus content dark-colored regions correspond to nepheline that is darker ( %). at higher SiO2 contents, which range from 46.4 to 54.8 wt%. – 2 5 Compared with nepheline in basalts [38, 46, 55 59], the 5.2.P O Whole-Rock>1wt Chemistry. The analytical major- and trace- nepheline-like crystals in the Zaolin basanite are even more element data for 12 samples of the basanite are listed in fi enriched in SiO2 and Al2O3 and are de cient in alkalis Table 1. The oxide compositions have a narrow range: ( %), which suggests that the basanitic : – : %, : – : %, : ff – : % : – : % : – : 2 magma was poorly di erentiated and crystallized at the time , , SiO 2 2 % : – : 2 % : –2 3: % ofNa crystalO+K growth.O < 14 Calculations wt show that the Si contents of =40, 09 44 30 wt TiO =222, 2 43 wt Al O =1091, : – : 2 3 % : – : % the nepheline-like crystals are lower than those of normative 11 61 wt Fe O =3, 39 4 65 wt FeO = 7 02, 10 01 : – : % : – : % : – : feldspar but higher than those of normative nepheline. Rela- wt MnO =, 0 17 0 19 wt MgO, = 9 02 11 49 wt % : – : 2% 2 tive to synthesized silicon-rich nepheline [55], based on 8 CaO, = and 9 10 12 35 wt Na O=3, with33 Na42O75 wtK2O. TheK O= loss 2 5 – 2 oxygens, the nepheline has very low Na + K, high Si + Al on1 10 ignition2 47 wt (LOI)P isO 1.98=1125.46 wt%,1 23 wt whichCO is slightly=017 lower3 80 3+ 2 +Fe ( 4.0), and minor Mg and Ca. However, considering wtthan the totalH O=1 content94 of3 12 CO wt2 +H2O. The LOI> should be a that the Ca contents are very low and those of Mg a little function of the content of carbonate and serpentine because higher, we> speculate that the nepheline-like crystals contain the samples are fresh and show negligible alteration. Other minor pyroxene or occurred as solid solution with minor basanites have Al2O3 and CaO contents that are commonly – – – pyroxene, as inferred from the ternary diopside nepheline 12.0 wt% and 10.0 wt%, respectively [51, 62 65], or Al2O3 sanidine system at 2 GPa [60]. Except for a few analysis contents of 12.0 wt% [66]. In comparison, the Zaolin basa- points (Supplementary Data Table 5), the compositions are >nite has lower> Al2O3 and CaO (except one sample, ZX14- fi fi restricted to the eld de ned by the Barth join, and the 38), which likely> explains the lack of plagioclase that crystal- quartz end-member exceeds 40 (Table 1), which might be lized from the magma. In a total alkali–silica (TAS) classifica- relevant to the nepheline in the basanite appearing in a tion diagram (Figure 7), the data fall in the basanite field. quenched glass or metastable phase [61] and containing Based on the various aforementioned features, including minor diopside [60]. SiO2 contents of 50 wt% and normative nepheline and

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 10 LITHOSPHERE

16 1000

12 Tephritic photolite 100 10 Photolitic tephrite

O (wt. %) Tranchyandesite 2 8

Basaltic trachyandesite O+K

Trachytic Rock/chondrite 2 6 10 basalt Na 4 Basanite

Basaltic Picritic Basalt Andesite Dacite rhyodacite 2 basalt andesite 1 0 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 40 45 50 55 60 65 70 75 80 SiO (wt. %) 2 (a) Figure 7: (Na2O+K2O) versus SiO2 diagram of the Zaolin basanite 1000 (classiﬁcation from [126]). The plotted data were adjusted for LOI, and the oxide contents were recalculated to 100%.

olivine contents of 10%, the rock samples can be classified as basanite. The high Mg# (0.75–0.66) ( 100 ð Þ ) values> imply that the basanitic magma is close to primary2+ magma [67]. The TFeO/MgOMg# ratios = atomic lie in Mg/ the – rangeMg + of Fe 1.1 1.3, showing that the magma experienced minor differentiation. 10 The Zaolin basanite is characterized by high contents of mantle Rock/primitive Ni (244–299 ppm), Cr (307–389 ppm), Ba (352–618 ppm), and Sr (1183–1466 ppm), reflecting the characteristics of primary magma [67]. In primitive-mantle-normalized spider- grams (Figure 8(a)), all samples show overall enrichment in 1 P Y K U Sr Ti Er Ta Zr La Ba Lu Pb Eu Ce Tb Rb Hf Yb Dy Nd Gd Ho Nb Sm highly incompatible elements relative to less incompatible Tm elements, with positive Nb and Ta anomalies and negative (b) K and Pb anomalies, but no depletion of high-field-strength CBSEC MORB elements (HFSEs), similar to the patterns of oceanic island OIB Zaoline basanite basalt (OIB; [68]) and of Cenozoic basalts in southeastern China (CBSEC) (Figure 8). The chondrite-normalized Figure 8: Trace-element variation diagrams for the Zaolin basanite. rare-earth element (REE) patterns of the basanite samples (a) Chondrite-normalized REE diagrams (chondrite REE data are characterized by enrichment of light REEs (LREEs) from [127]). (b) Primitive-mantle-normalized spider diagrams of ( : – : ) and a lack of Eu or Ce anomalies incompatible elements for the basanite (primitive-mantle data (Figure 8), implying the absence of low-temperature alter- from [127]). For comparison, the average compositions of present- day OIB [68] and Cenozoic basalts in southeastern China (CBSEC; ation and plagioclase fractional crystallization. High LREE La/Yb= 46 1 53 8 [128]) are also plotted. contents (La–Eu: 256–318 ppm) and Gd/Yb ratios (6.0–6.7) and low heavy REE (HREE) contents (Gd–Lu: 18.7– 21.6 ppm) indicate residual garnet in the source. The samples between DMM and EMI (Figure 9). Accordingly, crustal con- also show strong negative Ti anomalies and weak negative Zr tamination is inferred to have been negligible. and Hf anomalies, with high Zr/Hf ratios of 38.0–46.0, also similar to those of OIB [69] and CBSEC (Figure 8). 5.4. Geochronology of the Basanite. To determine the age of crystallization of the basanite, large and high-density phenocrysts and xenocrysts were removed by handpicking and 5.3. Sr–Nd Isotope Compositions. The Sr and Nd isotope gravity separation to maximize the potassium concentration. ratios of 12 basanite samples are listed in Table 2. The The Ar–Ar isotope data for the matrix of the basanite are 86Sr/87Sr ratios lie in a narrow range of 0.70358–0.70385 listed in Table 3. The analysis yielded a plateau age of : and the 143Nd/144Nd ratios in a narrow range of 0.512715– : , an isochron age of : : with an initial 40 36 : : 0.512913, similar to basanites in the Hefei basin [8], Nüshan Ar/ Ar ratio of , and an inverse isochron44 age05 : : 40 36 [70], Shandong [71], and Jiangsu [72] in eastern China ±052 Ma with an initial 43Ar/5±0Ar9Ma ratio of ε ε – (Figure 9). The calculated Nd(t) and Nd(0) values are (Figures 10(a) 10(c),298 respectively).2±46 Therefore, the basanitic – – fi 2.52 6.73 and 1.50 5.36, respectively. These isotope values 43magma5±2 cooling5Ma age is interpreted as 44 Ma, con rming298 ± that 14 are also similar to those of the OIB array intermediate the magmatism was unrelated to the large-scale Mesozoic

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 11

Table 2: Nd and Sr isotopic compositions of the Zaolin basanite from Jiangxi Province.

87 86 87 86 σ 87 86 143 144 147 144 σε ε Samples Rb/ Sr Sr/ Sr 2 Sr/ Sr(i) Nd/ Nd Sm/ Nd 2 Nd(0) Nd(t) TDM2(Ma) ZX14-35 0.047 0.703738 0.000011 0.70371 0.127 0.512636 0.000009 1.76 2.73 685 ZX14-36 0.057 0.703732 0.000015± 0.70370 0.125 0.512694 0.000008± 2.85 3.86 593 ZX14-37 0.072 0.703703 0.000008 0.70366 0.124 0.512626 0.000007 1.50 2.52 702 ZX14-38 0.067 0.703750 0.000014 0.70371 0.122 0.512767 0.000007 4.21 5.27 477 ZX14-39 0.082 0.703717 0.000010 0.70367 0.122 0.512789 0.000005 4.66 5.71 442 ZX14-40 0.059 0.703746 0.000014 0.70371 0.124 0.512763 0.000005 4.17 5.20 483 ZL23 0.053 0.703633 0.000014 0.70360 0.121 0.512634 0.000011 1.62 2.68 689 ZL24 0.073 0.703582 0.000011 0.70354 0.104 0.512792 0.000009 4.47 5.78 436 ZL25 0.093 0.703728 0.000011 0.70367 0.140 0.512788 0.000010 4.90 5.69 443 ZL26 0.065 0.703672 0.000008 0.70363 0.124 0.512788 0.000007 4.66 5.68 444 ZL27 0.171 0.703846 0.000010 0.70374 0.100 0.512841 0.000011 5.36 6.73 358 ZL28 0.169 0.703853 0.000010 0.70375 0.100 0.512761 0.000011 3.80 5.16 486 ZL29 0.073 0.703652 0.000011 0.70361 0.114 0.512827 0.000006 5.29 6.45 381

DMM 0.5133 MORB 0.5131 Nd Hawaii 144 0.5129 Southeast China Nd/

143 0.5127

Kergulelen 0.5125

0.5123 EMI 0.7022 0.7030 0.7038 0.7048 0.7054 0.7062 0.7070 87Sr/86Sr

Figure 9: 86Sr/87Sr and 143Nd/144Nd isotope data for the Zaolin basanite and comparison with data of Cenozoic basalts from southeastern China (from [2]) and other localities (from Stille et al., 1983; Storey et al., 1988). Small circles: this study.

– – W Cu metal mineralization (J3 K1) in the area. This age is the CO2-bearing system. As the water and CO2 contents in close to the 44 Ma age of lamprophyre [20] and the 41 Ma the Zaolin magma are unknown, we assumed a melt pressure age of alkaline basalt [19] in Jiangxi Province, reflecting an of 8–20 kbar and water contents of 0.5, 1.0, and 5.0 wt% [65]. Eocene magmatic event in this part of eastern China. Subse- According to equation 22 of Putirka [73], the calculated tem- quent alkaline basaltic magmatism migrated eastward and perature of the melt for these three water contents is 1254– southward and was widely distributed across eastern China 1320 C, 1243–1307 C, and 1160–1216 C, respectively. In – during the Miocene ([3, 9, 17]). contrast,° the calculated° melt temperature° is 1100 1202 C – with a pressure of 8 20 kbar based on the equation of Das-° 6. Discussion gupta et al. [75] for a CO2-bearing system. Combining these results for the two systems (hydrous and CO2-bearing), the 6.1. Temperature and Pressure of Formation of the Basanitic conditions for melt in equilibrium with xenocrystalline oliv- – – Magma. To estimate the temperature and pressure condi- ine are estimated to be 1100 1320 C with CO2 and 0.5 tions of the magma, olivine–melt equilibrium and clinopyr- 5.0 wt% H2O in the upper mantle [76].° oxene–melt equilibrium geothermobarometers were applied When the clinopyroxene–melt equilibrium geothermo- [73]. In Figure 11, only xenocrystalline olivine is in equilib- barometer [73] was applied, melt–clinopyroxene was found to be in disequilibrium on account of the large differential rium with the whole-rock chemical composition as melt with – ol–liq cpx liq : : of KD – from : : (Figure 11). If a barome- KD (Fe–Mg) close to [63]. CO2 would facilitate (Fe Mg) fl ter based on clinopyroxene only with equations 32c and 32d uid exsolution from such magma, meaning that the H2O of Putirka [73] is used with ð – Þ : – : , then content is low in some0 30 CO ±2 0-rich03 basanite and phonolite 0 27 ± 0 03 magmas, generally 1 wt% [74]. Therefore, we present results the calculated temperature–pressure (T–P) range is 932– – Fe Mg for two types of magmatic system: hydrous and CO2-bearing 1244 C and 10 26 kbar. TheseKD temperature=0282 estimates0 299 are [65, 73, 75], using< the geothermobarometer of Putirka [73] lower° than those for the melt in equilibrium with xenocrys- for the hydrous system and that of Dasgupta et al. [75] for talline olivine (1100–1320 C) as well as those for Zhejiang °

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 on 28 September 2021 by guest Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf 12

Table 3: 40Ar/39Ar analytical data for matrix from the basanite in Zhuxi tungsten-copper deposit area, Jiangxi Province. 40 39 (36 39 37 39 38 39 40 ∗ 39 39 −14 40 39 σ Heating step T ( C) ( Ar/ Ar)m Ar/ Ar)m ( Ar/ Ar)m ( Ar/ Ar)m Ar / Ar Ar ( 10 mol) Ar (%) Ar(Cum.) (%) Apparent (Ma) Sample: ZL-7, weight° = 44.64 mg, J = 0:005709 1 700 434.0325 1.4303 0.0000 0.3060 11.3718× 0.04 2.62 0.18 age ± 1 2 800 94.2414 0.3111 0.4608 0.0940 2.3361 0.94 2.48 4.21 : : 113 ± 33 3 850 61.8430 0.1969 0.3436 0.0614 3.6847 1.07 5.96 8.77 : : 23 90 ± 0 84 4 900 32.7495 0.0979 0.3016 0.0375 3.8385 2.11 11.72 17.81 : : 37 56 ± 0 74 5 940 17.0053 0.0435 0.3168 0.0247 4.1649 1.90 24.49 25.93 : : 39 11 ± 0 51 6 980 13.3335 0.0305 0.3995 0.0218 4.3555 1.96 32.66 34.32 : : 42 39 ± 0 55 7 1020 12.0611 0.0262 0.5889 0.0219 4.3725 1.38 36.24 40.25 : : 44 31 ± 0 55 8 1070 9.0551 0.0162 0.8178 0.0192 4.3298 8.14 47.79 75.11 : : 44 48 ± 0 77 9 1100 9.1751 0.0173 3.0583 0.0286 4.2967 5.46 46.71 98.47 : : 44 05 ± 0 45 10 1140 20.3865 0.0781 69.6492 0.1649 2.3808 0.31 11.02 99.80 : : 43 72 ± 0 46 11 1240 181.3000 0.6418 225.4088 0.1735 9.3106 0.05 4.20 100.00 24 4±24 93 ± 16 LITHOSPHERE LITHOSPHERE 13

0.0040 600

160 ZL-7 550 0.0035 AgeAge = 43.43.5±2.55±2.5 Ma 500 120 IncludesIncludes 4040Ar/Ar/36ArAr = 298298±14±14

Ar 450 � Ar 0.003 MSWDMSWD = 2.1

Plateau age = 44.05±0.52 Ma (1 ) 40 40 MSWD = 0.88 Ar/

Ar/ 400 40 Age (Ma) Age 80 980°C – 1100°C 40 39 0.0025 Includes 72.5% of the Ar 350 980 C – 1100 C 300 Age = 43.5±0.9 Ma 40 0.0020 Includes 40Ar/36Ar = 298.2±4.6 250 MSWD = 1.7

90 0.0015 200 0204060 80 100 0 0.0200 0.0400 0.0600 0.0800 0.1000 0.1200 0 20 40 60 39 40 Cumulative 39Ar percent 39Ar/40Ar Ar/ Ar

(a) (b) (c)

Figure 10: Ar–Ar isotope analytical spectrum of the Zaolin basanite: (a) plateau age; (b) isochron age; (c) inverse isochron age.

spheric mantle (≥1.0; [77]). De Paolo and Daley [78] also 95 considered that indicates an asthenospheric source and a lithospheric source. Melts originated from asthenosphericLa/Nb< mantle 1 have La/Ta ratios close to 10 – 90 [79]. The ZaolinLa/Nb> basanite 1 yields Nb/La ratios of 1.2 1.6 and Olivine Olivine La/Ta ratios of 11–13.4, suggesting that the melt was derived removal accumulation from an asthenospheric source but not lithospheric mantle 85 [80]. Zr/Ta and Nb/Hf ratios, which are independent of metasomatism, crustal contamination, and differentiation, can also indicate source characteristics. High Zr/Ta ( 200) and low Nb/Hf ( 4) ratios reflect a depleted source, whereas 80 low Zr/Ta ( 200) and high Nb/Hf ( 4) ratios indicate> an Magma mixing Fo(=100 ⨯ olivine Mg#) enriched asthenospheric< mantle source [81, 82]. The Zaolin Differentiation – basanite samples< have low Zr/Ta ratios> (50 55) and high 75 Nb/Hf ratios (12.0–16.3; Table 1). Furthermore, the high 143 144 86 87 ol-liq Nd/ Nd and low Sr/ Sr ratios, as well as the trace- KD(Fe-Mg) =0.30±0.03 and rare-element patterns, are in accordance with an OIB- 70 type asthenospheric source. These characteristics are consis- 40 50 60 70 80 90 tent with those of the Cenozoic alkaline basalts in eastern 100 ⨯ Mg# liquid China, which are generally thought to have been derived from low-degree partial melting of asthenospheric mantle Figure 11: Assessment of equilibrium between olivine and melt – – – ([3, 9, 14, 17, 30 34, 83 86]). based on the Fe Mg exchange reaction (Roeder and Emslie, 1970). Two likely sources have been identified for the Cenozoic alkaline basalts in eastern China: reconstructed silicon- Cenozoic tholeiitic and weakly alkaline basalts [14]. These deficient and silicon-enriched pyroxenite [85, 87] and car- lower estimates are probably attributable to the magma sys- bonated mantle peridotite containing minor eclogite and tem containing H2O and CO2, which causes a decrease in pyroxenite [39, 88]. The inclusions of ephritic–trachyandesi- the solvus line of the melt system. tic and tholeiitic glasses ( : – : %) in olivine phenocrysts of the alkaline basalts of eastern China are 6.2. Magma Source of the Basanite. Most of the Zaolin basa- thought to have been capturedSiO2 from=46 early4 56 melts2wt of the source, nite samples have relatively low LOI values of 2.2 to equivalent to pyroxenite [87]. However, much earlier stage 3.4 wt.% (Table 2), as well as Ba/Rb values (10.8–14.1 with a melts have been observed in anhydrous spinel and garnet mean of 12.0) similar to those of intraplate basalts ( 12; peridotite xenoliths in alkaline basalts of northeastern, north- [68]), suggesting that postmagmatic alteration of the samples ern, central, and southern China [89], in which melt inclu- fi was insigni cant. This inference is consistent with the petro-~ sions in olivine and pyroxene comprise SiO2- and alkaline- – % graphic observations, which show that the samples are gener- rich glasses ( and K2O Na2O), with fi – – ally fresh, and con rms that the whole-rock geochemical and Al2O3 CaO TiO2-rich clinopyroxene, spinel, and feldspar mineral chemical data are reliable. daughter crystalsSiO [89].2 =60 These68 wt melt inclusions> are interpreted Some elements and isotopes can be used to determine the to be captive mantle fluid materials and are multistage inclu- source of basalt, such as HFSEs being depleted relative to sions [87, 89–92]. Thus, we infer that the captive early melts LREEs in the lithospheric mantle, with the Nb/La ratio being within and between grains would have been affected by mix- lower in OIBs originating from the lithospheric mantle ing, crystallization, and differentiation during magma ascent, (≤0.5) and higher in OIBs originating from the astheno- with the components captured by olivine and pyroxene in the

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 14 LITHOSPHERE

magma being evolved products, meaning that the glasses Petrologic experiments have confirmed that low-degree entrained in olivines are not necessarily representative of partial melting of carbonated peridotite can yield nepheline- the primary composition of the source. In contrast, the high bearing silicate magma [75, 102]. Moreover, CO2-bearing Mg# and positive εNd(t) values of the Zaolin basanite show melt and fluid inclusions [70, 103–106] and carbonate- that the source underwent a low degree of partial melting. bearing pyrolite xenoliths [49] in basalt are commonly The inclusion assemblage in olivine phenocrysts is Ti- observed, showing that carbonate exists in the mantle and fl diopside + spinel + nepheline + sanidine, similar to the participates in mantle reactions. Such CO2-bearing uid Zaolin basanite itself (Table 1; Figure 5(a)), suggesting that inclusions record very high pressures, corresponding to the early melt resembled the late melt compositionally and near-mantle depths [104]. The presence of carbonate min- that the melt experienced weak differentiation. In the basa- erals; carbonate-like trace-element patterns of K, Pb, Ti, nite, the olivine phenocrysts that crystallized from magma and Zr; negative Hf anomalies; high Zr/Hf ratios (38–46); are rarely zoned, and they have narrow rims. The clinopyr- and high Ca/Al ratios of olivine in the Zaolin basanite oxene phenocrysts are also rarely zoned, and most of the (Figures 4(a), 5(c)–5(g), and 8(b); Tables 1 and 2) suggests clinopyroxene occurs in the matrix. The melt might have that the source of the alkaline basalts of southeastern China resided within the upper mantle, considering the above- was carbonated peridotite [39, 45, 107]. calculated T–P conditions of olivine and clinopyroxene crystallization. 6.3. Evolution of the Basanite. Various studies have been con- Zeng et al. [39] proposed that the source of alkaline ducted on alkaline basalts and their relationship to carbonate basalts in eastern China was mainly carbonated peridotite [46, 49, 52, 53]. Experiments have shown that partial melting with minor eclogite, on the basis that carbonatite is highly of carbonated peridotite can generate carbonate melting, or enriched in incompatible elements but not in K, Zr, Hf, or CO2-rich silicate melting and carbonate liquidation, or Ti and has extremely high Zr/Hf and Ca/Al ratios. K, Zr, carbonated silicate melt after crystal fractionation and differ- Hf, and Ti anomalies are expected on account of their much entiation [108, 109]. Carbonate ocelli in silicate (basalt, kim- higher bulk partition coefficients compared with REEs under berlite, and eclogite), which were initially explained in terms mantle conditions for carbonatite melt [93]. The addition of of liquidation between silicate and carbonate liquids, have fl a carbonate component or CO2 ux to peridotite can lead to subsequently been recognized as the products of magmatic enrichment in REEs but not in K, Zr, Hf, or Ti [64]. Trace- differentiation or evolved products [109]. The early crystal- element modeling using depleted upper mantle plus 0.3 and lized carbonate from a carbonate–silicate melt comprises 1.0 wt% carbonatite yielded similar trace-element patterns dolomite and magnesium calcite, and the late-crystallized to those of natural alkaline basalts, as well as high Zr/Hf carbonate is siderite [49]. Carbonate-bearing silicate magma ratios. Silica-deficient garnet pyroxenite or eclogite cannot dissociates along the solidus line and forms coprecipitated produce negative Ti anomalies unless there is residual rutile carbonate and silicate crystals. As the surface energy of car- in the mantle source, which would result in Ti, Nb, and Ta bonate is higher than that of silicate melt, carbonate melt depletion in melts [94]. However, zircon would not signifi- exists between silicate crystals that are unable to indepen- cantly fractionate Zr from Hf [95]. Therefore, garnet pyroxe- dently migrate from the silicate melt and are removed only nite (garnet pyroxene) cannot produce melts with both after crystallization of the silicate or liquidation [109, 110]. high Zr/Hf ratios and negative Zr and Hf anomalies. Eclogite Therefore, carbonate crystallizes later than silicate melt. (garnet pyroxene)< can produce melts with negative Zr and Though carbonate-bearing basalts are rarely reported in Hf anomalies but with low Zr/Hf ratios [96]. Therefore, Cenozoic in China, they are much more common in Meso- pyroxenite> and eclogite cannot explain the fractionation of zoic alkaline basalts [54, 111, 112]. These rocks are all found Zr and Hf and are not the main contributors to alkaline in sedimentary carbonate strata, and the wall rock with high fl basalts [66]. fCO2 probably prevents CO2-rich uids of alkaline basaltic fl ff Lithospheric mantle metasomatized by CO2 uid yields magma from di using during solidus depression and magma fi a silica-de cient melt that shows high CaO/Al2O3 and upwelling [54, 111, 112]. The studied Zaolin basanite also La/Zr ratios and low Ti/Eu ratios [97–99]. The Zaolin basa- outcrops within the Permian carbonate strata. Carbonate – – nite has LaN/ZrN (3.5 4.4) and TiN/EuN (0.6 0.7) ratios minerals in this basanite occur with two types of texture: close to those of the calculated parental magma ( polycrystalline (which might have formed during late, rapid : – : ; : – : ) in equilibrium with car- crystallization) and augen-like. The MgO + FeO content of – N N bonatite liquid [100]. The HfN/YN ratios (4.1 4.4)La /Zr of the= the carbonate in the basanite is much higher than 50 wt% 3basanite8 11 3 areTi alsoN/Eu similarN =018 to those0 54 of an alkaline basalt com- (Supplementary Data Table 4), which means that this plex in Brazil (3.9–9.4) [100]. In addition, olivine with high carbonate was miscible with basanitic silicate magma at Ca/Al ratios overlapping those of HIMU basalt is inter- high temperature and pressure and separated later during preted to be related to carbonated metasomatism of the sub- solidus depression, according to the experimental results of lithospheric mantle [101]. Some of the olivine (analysis Lee and Wyllie [109]. The carbonates have heterogeneous points 20, 39, and 72 in Supplementary Data Table 1) in chemical compositions (Figures 5(c)–5(e), coarser grains), the Zaolin basanite have high Ca/Al ratios (36.5, 29.8, and indicating a change from high-temperature miscible to low- 31.7, respectively; : ). Together, the above temperature immiscible phases. Furthermore, the Zaolin characteristics indicate the carbonated nature of the source basanite carbonates differ markedly from the carbonate of for the Zaolin basanite,others but < not 16 a2 metasomatic origin. the host rock (Permian strata), which is mainly calcite. Few

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 15

fractures are observed around the carbonate augens and 0.6 siderite, and some of the carbonate minerals are interspersed Hawaiian with diopside (Figure 5(c)) and Ti-magnesite (Figure 4(a)), tholeiite olivines suggesting that the carbonate melt produced minerals similar 0.4 in size to that of diopside in the matrix and crystallized fi around the silicates and oxides. The ner siderite observed Hainan in the silicate minerals of diopside, sanidine, and nepheline- basal like minerals probably coprecipitated with these minerals 0.2 olivines fi Fractional (Figures 5(c), 5(d), and 5(g), ne-grained areas). The other (wt. %) in olivine NiO type of carbonate, distributed along the margins of, and crystallization Common olivines fractures in, olivine phenocrysts, was formed by late-stage 0 hydrothermal fluid from the melt when P–T conditions had 45 50 55 60 65 70 75 80 85 90 95 dropped substantially. The hydrothermal fluids likely Fo (%) separated from the basanitic magma as a result of the Figure – hydrous nature of the melt and CO escaping from the 12: NiO Fo compositional variations of olivine phenocrysts 2 and xenocrysts (after [118]). The fractional crystallization trend is magma during ascent at shallow levels in the crust. from Sato (1977). The field “common olivines” depicts the The lack of zoning in olivine and clinopyroxene and the compositional range of olivines from peridotite xenoliths, orogenic high Mg# of the melt indicate that the residence time of the massifs and ophiolites, oceanic abyssal basalts, and MORB [117], melt within the crust was short and that polybaric crystalliza- whereas “Hawaiian tholeiite olivines” denotes the range of olivines tion did not occur [63]. The low Fo values (79–85) of olivine, from Hawaiian tholeiite basalts [117] and the “Hainan basalt in contrast to the high Mg# values and the existence of man- olivines” field is from Wang et al. [24]. tle xenoliths, show that olivine and clinopyroxene accumu- lated in the melt but that differentiation was negligible. In addition, the high Ni and Cr contents of the magma also sug- blages and chemistry, geochemistry, and source. During the gest insignificant fractional crystallization of olivine and neg- evolution of the basanitic magma, melt converged and crys- ligible fractional crystallization of clinopyroxene in the tallized at mantle depths, and olivine and clinopyroxene phe- Zaolin basanite [113]. Zr/Y and Zr/Nb ratios also can indi- nocrysts grew. Owing to the rapid ascent of the magma under cate the degree of partial melting, with high Zr/Y and low high-temperature ( 1250 C) and low-viscosity (low-SiO2) Zr/Nb ratios indicating low-degree partial melting and vice conditions, olivine and clinopyroxene° did not readily crystal- ff versa [114]. The Zaolin basanite is inferred to have originated lize and di erentiate,~ meaning that crystal sizes were small from low-degree partial melting on account of its high Zr/Y ( 0.5 mm), and the melt had high Mg# values and high Cr (11.1–12.8) and low Zr/Nb (2.8–3.4) ratios, consistent with and Ni contents and was in disequilibrium with olivine and the values of Mg#, Cr, and Ni [80]. pyroxene.< Microliths of clinopyroxene and olivine, followed During the partial melting of garnet lherzolite and spinel by spinel, sanidine + Si-rich nepheline, and carbonate, crys- lherzolite, garnet preferentially incorporates HREEs relative tallized while the melt ascended through the crust. Ca was to spinel [115, 116], resulting in high La/Yb and Gd/Yb ratios incorporated largely into diopside and less readily into – in the melt. The chondrite-normalized REE patterns of the MgCO3 FeCO3 [50], leading to the formation of carbonate Zaolin basanite indicate a garnet residue in the source and (and feldspar) and late-crystallized minerals poor in Ca. Dur- that the melt had high La/Yb (46–54) and Gd/Yb ratios ing the late stage, Al and Si entered mainly the sanidine and (6.1–6.7) and low HREE contents (18.7–21.6 ppm; Table 2). nepheline-like melt. K was mainly consumed and incorpo- In addition, all of the olivines in the basanite plot in the com- rated into sanidine. Na and the remaining K, as well as Si, mon olivine field for peridotite xenoliths, orogenic massifs were incorporated in the nepheline, which was the last min- and ophiolites, abyssal peridotite, and MORB [117], without eral to crystallize, with variable SiO2 contents ranging from an abnormally high NiO content, suggesting that the source 45 to 52 wt% (Table 1). No plagioclase was formed in the lacked a pyroxenite component (Figure 12; [118]). The fol- magma owing to the insufficient Si, Al, and Ca in the melt. lowing factors indicate that apatite existed in the source: the Carbonate melt crystallized late and was controlled mainly Zaolin basanite contains more P2O5 ( 1 wt%) than other by early crystallized silicates; these carbonates formed as basanites ( 1 wt%) [51, 62–65], the melt inclusions of olivine polycrystalline and ocellar carbonates, with sizes similar to in the Baekdusan basanite [119] and the> Ross Island alkaline those of the silicate minerals [110], as either phenocrysts or magmas [74],< and the observed positive P anomaly in in the matrix. primitive-mantle-normalized REE patterns. When partial Previous studies on mantle xenoliths captured by Ceno- melting occurred, apatite would have readily formed in the zoic alkaline basalts show that the lithospheric mantle of melt, thereby increasing the positive P anomaly. In addition, eastern China is fertile, reflecting the upwelling of astheno- experiments have shown that when the melt temperature spheric mantle that replaced ancient lithospheric mantle ≥ drops below 1100 C and SiO2 is 48 wt%, apatite starts to [20, 44, 86, 120]. South China is also considered to have fer- crystallize from the° melt [74], which might explain the pres- tile juvenile lithospheric mantle and locally preserved relict ence of apatite in the matrix of the Zaolin basanite. Proterozoic mantle [20, 44]. The Cr# of spinel and clinopyr- In accordance with the above findings, the evolution of oxene is a sensitive indicator of the extent to which mantle the Zaolin basanite can be inferred from its mineral assem- peridotites have lost their basaltic components [20, 67, 121].

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 16 LITHOSPHERE

The Zaolin basanite entrained mantle xenocrysts of olivine 7. Conclusion and spinel, in which the olivine has a very narrow range of Fo (89.6–90.7), similar to the values for peridotite xeno- A systematic study of the petrography, mineral chemistry, – – liths in eastern China. However, the Cr# (0.28–0.64) and major and trace elements, Sr Nd isotopes, and Ar Ar ages Mg# (0.52–0.68) values of the spinels are refractory rather of the Zaolin basanite from southeastern China allows us to than fertile, reflecting that the lithospheric mantle is relict. constrain its petrogenesis including forming conditions, source, and evolution processes and thereby the origin of Three spinel xenocrysts contain much higher Cr2O3 continental basalts. The major conclusions of the study are ( 40 wt%) and lower Al2O3 ( 12.0 wt%) contents (Supple- mentary Data Table 3) than those of spinel lherzolite and as follows. harzburgite> xenoliths in alkaline< basalts in eastern China ([5, 9, 20, 44]) and resemble those from peridotite (1) The basanitic magma was in equilibrium with xeno- – inclusions in kimberlite [122]. These features suggest that cryst olivine at 1100 1320 C and mantle depths. the lithospheric mantle beneath Jingdezhen underwent Olivine and clinopyroxene phenocrysts° might have high-degree partial melting and partly formed at very high been retained in the mantle and later rapidly pressure, with the residual lithospheric mantle fragments ascended to the surface in the melt with only a short being captured by rapidly ascending basanitic melt and residence time in the crust brought to the surface. (2) The Zaolin basanite contains mantle xenocrysts, i.e., Our calculations show that the Zaolin basanite melt was kink-banded olivines, olivines + orthopyroxenes, – in equilibrium with olivine at 1160 1320 C and pressures and chromites, and shows high Cr and Ni contents – of 8 20 kbar. Considering the existence of° carbonate melt and depleted Sr and Nd isotopes. These features – as well as garnet (2.5 3.0 GPa) in the source, the Zaolin basa- indicate an origin from low-degree partial melting nitic magma is inferred to have been derived from a depth of of asthenosphere mantle and enriched mantle, which 70 km [62, 109, 123, 124]. Spinels in the matrix of the Zaolin was subsequently metasomatized by carbonate melt basanite are clearly inherited from spinel of the relict litho- (3) The evolution of the Zaolin basanite was established >spheric mantle, as shown by the high Cr2O3 contents of these spinels, their compositional inhomogeneity, and the presence from the mineral assemblages and chemistry, geochemistry, and source. During rapid ascent, the basa- of both Cr2O3 and TiO2 in single spinel grains (Table 1). As the basanitic magma formed at high temperature and given nitic melt captured fragments of lithospheric mantle. that spinel has a lower melting point than silicates (olivine Small amount of olivine and pyroxene phenocrysts and pyroxene), the trapped spinel from the relict lithospheric began to crystallize in the spinel stability field at high mantle was easily melted and reacted with alkaline silicate T and P. CO2 largely dispersed, with only a small melt, then was dispersed and subsequently crystallized late amount being retained in the silicate melt with the when the temperature dropped during magma ascent. Owing pressure decrease during ascent. Olivine and pyrox- to the slow rate of Cr3+ diffusion, the characteristics of high ene were first crystallized and then carbonate and spinel, followed by sanidine and then nepheline. Owing Cr2O3 content and compositional inhomogeneity of the dispersed spinel were retained in the matrix. Therefore, the to the lack of Si, Al, and Ca, no plagioclase formed in occurrence of the Zaolin basanite illustrates that the litho- the magma spheric mantle under Jingdezhen, Jiangxi Province, in the (4) The lithospheric mantle beneath the Jingdezhen area Yangtze Block has not been completely replaced by upwelling in Jiangxi Province was probably relict Proterozoic asthenosphere mantle and was captive by the basanitic mantle that underwent a high degree of partial melt- magma generated by low-degree partial melting of deep car- ing or melt extraction. In contrast to the fertile litho- bonated peridotite. spheric mantle of eastern China, the lithospheric Major element and REE concentrations and U–Th–Pb, – – mantle in Jiangxi Province has not been completely Sm Nd, and Rb Sr isotope systematics reported for Ceno- replaced by asthenospheric mantle. The occurrence zoic volcanic rocks in northeastern and eastern China have fi of the Zaolin basanite, as well as other alkaline basalt con rmed that these volcanic rocks, characteristically lacking or lamprophyre dikes, shows that Eocene (ca. 44 Ma) the calc-alkaline suite of orogenic belts, were emplaced in a magmatism ever took place in southeastern China. rift system that developed as a result of subduction of the fi This magmatism was related to the rift tectonic set- western Paci c plate beneath the eastern Asiatic continental ting of the eastern China continent margin. This subduction and rifting caused extension- induced passive asthenospheric upwelling and decompres- sion melting ([35] and references therein), thereby explain- Data Availability ing the petrogenesis of Cenozoic basalts in eastern China. Our Ar–Ar dating shows that the Zaolin basanite was formed Representative microprobe data for minerals in the Zaolin at 44 Ma, similar to the ages of the Guangfeng alkaline basalt basanite are listed in Supplementary Data Tables 1–6. The dike and the Anyuan lamprophyre dike. The dynamic setting analytical major- and trace-element data for 12 samples of inferred for the Cenozoic basalts in eastern China can also the basanite are listed in Table 1. The Sr and Nd isotope reasonably explain the dynamics for the Zaolin basanite, ratios of 12 basanite samples are listed in Table 2. The Ar– although more evidence is needed. Ar isotope data for the matrix of the basanite are listed in

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 17

Table 3. Figure captions Figure 1: simplified Cenozoic volcanic for the Zaolin basanite and comparison with data of geology and tectonic framework of eastern China (modified Cenozoic basalts from southeastern China (from [2]) and after E and [9, 39]). Figure 2: geological map of the Zaolin other localities (from Stille et al., 1983; Storey et al., 1988). area, Jingdezhen, Jiangxi Province (modified after [37, 45]). Small circles: this study. Figure 10: Ar–Ar isotope analytical Figure 3: field photographs and photomicrographs of the spectrum of the Zaolin basanite: (a) plateau age; (b) isochron Zaolin basanite: (a, b) photographs showing the basanite age; (c) inverse isochron age. Figure 11: assessment of (dotted white line) within Permian carbonate strata and equilibrium between olivine and melt based on the Fe–Mg displaced by a fault (solid white line); (c) photograph of a exchange reaction (Roeder and Emslie, 1970). Figure 12: hand specimen (ZL-36); (d) photomicrograph of the Zaolin NiO–Fo compositional variations of olivine phenocrysts and basanite (cross-polarized light) showing porphyritic texture xenocrysts (after [118]). The fractional crystallization trend with olivine phenocrysts; (e) clinopyroxene phenocrysts is from Sato (1977). The field “common olivines” depicts the (plane-polarized light). ol: olivine; Cpx: clinopyroxene. compositional range of olivines from peridotite xenoliths, Figure 4: photomicrographs of basanite under an optical orogenic massifs and ophiolites, oceanic abyssal basalts, and microscope. (a) Augen carbonates (transmitted light). The MORB [117], whereas “Hawaiian tholeiite olivines” denotes cpx occurs as columnar crystals in the matrix. Spinel occurs the range of olivines from Hawaiian tholeiite basalts [117] as inclusions in carbonate and between carbonate grains. and the “Hainan basalt olivines” field is from Wang et al. [24]. (b) Kink-banded olivine xenocryst with a clear margin (cross-polarized light). Other phenocrysts are olivine that Conflicts of Interest crystallized from magma. (c) Ol + opx xenocrysts (reflected light). (d) Brown spinel xenocryst and tiny dark spinels The authors declare that they have no conflicts of interest. (transmitted light). ol: olivine; opx: orthopyroxene; cpx: clinopyroxene; sp: spinel; Car: carbonate; rim: rim of Acknowledgments olivine or spinel. Figure 5: back-scattered electron images of the Zaolin basanite. (a) Inclusions of cpx, sp, and ne in This work was supported by the Program of Department olivine, similar to the mineral assemblage in the matrix. of Science and Technology (No. 2016YFC0600203), the Needle-like apatites occur in the matrix. (b) Zoned National Natural Science Foundation of China (No. clinopyroxene phenocryst. In the matrix, sanidine and 41873059), and the China Geological Survey Project (No. nepheline appear as light and dark, respectively, distributed DD20190001). We thank Dr. Zhiming Yang for discussions between columnar clinopyroxene grains. (c) Augen of on petrologic genesis. We express gratitude to Dr. Xiaohong siderite interspersed with cpx and sp. (d) Augen of Mao for assistance with microprobe analyses at the Key Lab- carbonate showing distinct phase separation, with the dark oratory of Continental Dynamics, Department of Natural parts of the carbonate being Mg-rich magnesite and light Resources, China. We also thank geological engineers includ- parts being Fe-rich siderite. (e) Heterogeneous carbonate ing Limin Shu, Luchuan Luo, and Tao Xie from the 912 Geological Team, Bureau of Geology and Mineral Resources with MgO and FeO contents of 50%. (f) Spinel xenocryst fi eroded by magma, showing a Ti- and Fe-rich rim and of Jiangxi Province, for their help with eld sampling. Com- ments and suggestions from Dr. Leonid Danyushevsky fractures, whereas its inner part~ is primarily chromite, rich in Mg and Cr. (g) Eroded spinel with several compositional greatly improved an earlier version of the manuscript. zones. Near the spinel is siderite coexisting with ne and cpx. (h) Eroded spinel, rich in Ti and Fe, or Ti-magnesite. Supplementary Materials The tiny (light-colored) minerals scattered in the matrix of Supplementary Data Table 1: representative microprobe data images (a–h) are Cr–Ti–Mg–Fe spinel. ol: olivine; cpx: for olivine from the Zaolin basanite, Jiangxi Province. Sup- clinopyroxene; sp: spinel; Car: carbonate; ap: apatite; ne: plementary Data Table 2: representative microprobe data nepheline; sa: sanidine. Figure 6: classification of pyroxene for clinopyroxene from the Zaolin basanite, Jiangxi Province. [125] into diopside, augite, pigeonite, enstatite, and Supplementary Data Table 3: representative microprobe data ferrosilite. The data point in the enstatite field is of opx for spinel from the Zaolin basanite, Jiangxi Province. Supple- interspersed with olivine xenocrysts. The circle near the mentary Data Table 4: representative microprobe data for center, on the diopside–augite boundary, represents the nepheline from the Zaolin basanite, Jiangxi Province. Supple- compositions of the cpx near felsic enclaves. Figure 7: mentary Data Table 5: representative microprobe data for (Na2O + K2O) versus SiO2 diagram of the Zaolin basanite sanidine from the Zaolin basanite, Jiangxi Province. Supple- (classification from [126]). The plotted data were adjusted mentary Data Table 6: representative microprobe data for for LOI, and the oxide contents were recalculated to 100%. carbonate from the Zaolin basanite, Jiangxi Province. Figure 8: trace-element variation diagrams for the Zaolin (Supplementary Materials) basanite. (a) Chondrite-normalized REE diagrams (chondrite REE data from [127]). (b) Primitive-mantle-normalized References spider diagrams of incompatible elements for the basanite (primitive-mantle data from [127]). For comparison, the [1] Y. Wang, Z. F. Zhao, Y. F. Zheng, and J. J. Zhang, “Geochem- average compositions of present-day OIB [68] and Cenozoic ical constraints on the nature of mantle source for Cenozoic basalts in southeastern China (CBSEC; [128]) are also continental basalts in east-central China,” Lithos, vol. 125, plotted. Figure 9: 86Sr/87Sr and 143Nd/144Nd isotope data no. 3-4, pp. 940–955, 2011.

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 18 LITHOSPHERE

[2] H. B. Zou, A. Zindler, X. S. Xu, and Q. Qi, “Major, trace ele- [17] S. X. Hu, Y. Y. Zao, Z. H. Hu, J. H. Guo, and B. H. Xu, “Evo- ment, and Nd, Sr and Pb isotope studies of Cenozoic basalts lution and development of tectonics and magmatism at the in SE China: mantle sources, regional variations, and tectonic active continental margin of the East China during Mesozoic significance,” Chemical Geology, vol. 171, no. 1-2, pp. 33–47, and Cenozoic,” Acta Petrologica Sinica, vol. 10, pp. 370–381, 2000. 1994. [3] X. S. Xu and X. Xie, “Late Mesozoic–Cenozoic basaltic rocks [18] H. F. Wang, X. C. Yang, B. Q. Zhu, S. K. Fan, and T. M. Dai, and crust mantle interaction, SE China,” Geological Journal of “K–Ar geochronology and evolution of Cenozoic volcanic China Universities, vol. 11, pp. 318–334, 2005. rocks in eastern China,” Geochimica, vol. 1, pp. 1–12, 1988. [4] A. R. Basu, Wang Junwen, Huang Wankang, Xie Guanghong, [19] D. G. Yu, F. W. Ye, and Y. Wang, “Active succession estab- and M. Tatsumoto, “Major element, REE, and Pb, Nd and Sr lishment for volcanic intrusive complex in middle–late Creta- isotopic geochemistry of Cenozoic volcanic rocks of eastern ceous in Guangfeng, Jiangxi and its geological implication,” China: implications for their origin from suboceanic-type Geotectonica et Metallogenia, vol. 25, pp. 271–276, 2001. mantle reservoirs,” Earth and Planetary Science Letters, [20] J. P. Zheng, S. Y. O'Reilly, W. L. Griffin, M. Zhang, F. Lu, and vol. 105, no. 1-3, pp. 149–169, 1991. G. L. Liu, “Nature and evolution of Mesozoic-Cenozoic litho- [5] J. S. Chi, The study of Cenozoic basalts and the upper mantle spheric mantle beneath the Cathaysia block, SE China,” beneath eastern China (attachment: kimberlites), Published Lithos, vol. 74, no. 1-2, pp. 41–65, 2004. by China University of Geosciences, Wuhan, 1988. [21] I. Metcalfe, “Allochthonous terrane processes in Southeast [6] S. L. Chung, B. M. Jahn, S. J. Chen, T. Lee, and C. H. Chen, Asia,” Philosophical Transactions of the Royal Society of Lon- “Miocene basalts in northwestern Taiwan: evidence for EM- don, vol. 331, pp. 625–640, 1990. ” type mantle sources in the continental lithosphere, Geochi- [22] K. Tu, M. F. Flower, R. W. Carlson, M. Zhang, and G. Xie, “Sr, – mica et Cosmochimica Acta, vol. 59, no. 3, pp. 549 555, 1995. Nd, and Pb isotopic compositions of Hainan basalts (South [7] S. L. Chung, S. S. Sun, K. Tu, C. H. Chen, and C. Y. Lee, “Late China): implications for a subcontinental lithosphere Dupal Cenozoic basaltic volcanism around the Taiwan Strait, SE source,” Geology, vol. 19, no. 6, pp. 567–569, 1991. China: product of lithosphere-asthenosphere interaction dur- [23] S. Y. Yu, Y. G. Xu, S. H. Zhou et al., “Late Cenozoic basaltic ” ing continental extension, Chemical Geology, vol. 112, no. 1- lavas from the Changbaishan-Baoqing Volcanic Belt, NE – 2, pp. 1 20, 1994. China: products of lithosphere-asthenosphere interaction [8] B. L. Cong, Q. C. Wang, H. Z. Zhang, X. Yan, and L. L. Jiang, induced by subduction of the Pacific plate,” Journal of Asian “Petrogenesis of Cenozoic volcanic rocks in Hefei basin, Earth Sciences, vol. 164, pp. 260–273, 2018. ” – China, Acta Petrologica Sinica, vol. 12, pp. 370 381, 1996. [24] X. C. Wang, Z. X. Li, X. H. Li et al., “Temperature, pressure, [9] M. L. E and D. S. Zhao, Cenozoic basalts of eastern China and and composition of the mantle source region of Late Ceno- their deep sourced xenoliths, Scientific Publishing House, Bei- zoic basalts in Hainan Island, SE Asia: a consequence of a jing, 1987. young thermal mantle plume close to subduction zones?,” [10] Q. Fan and P. R. Hooper, “The Cenozoic basaltic rocks of Journal of Petrology, vol. 53, no. 1, pp. 177–233, 2012. eastern China: petrology and chemical composition,” Journal [25] X. C. Wang, Z. X. Li, X. H. Li, J. Li, Y. G. Xu, and X. H. Li, of Petrology, vol. 32, no. 4, pp. 765–810, 1991. “Identification of an ancient mantle reservoir and young [11] W. M. Fan and M. A. Menzies, “Geochemistry of volcanic recycled materials in the source region of a young mantle rocks and ultramafic xenoliths from eastern China: implica- plume: implications for potential linkages between plume tions for the structure of the lower lithosphere,” Geotectonica and plate tectonics,” Earth and Planetary Science Letters, – et Metallogenia, vol. 18, pp. 332–346, 1994. vol. 377-378, pp. 248 259, 2013. [12] M. F. Flower, M. Zhang, C. Y. Chen, K. Tu, and G. Xie, “Mag- [26] X. C. Wang, S. A. Wilde, Q. L. Li, and Y. N. Yang, “Continen- fl matism in the South China Basin: 2. Post-spreading Quater- tal ood basalts derived from the hydrous mantle transition ” nary basalts from Hainan Island, south China,” Chemical zone, Nature, vol. 6, no. 1, 2015. Geology, vol. 97, no. 1-2, pp. 65–87, 1992. [27] X. Yu, L. H. Chen, and G. Zeng, “Growing magma chambers fl ” fi [13] X. H. Li, “Cretaceous magmatism and lithospheric extension control the distribution of small-scale ood basalts, Scienti c in Southeast China,” Journal of Asian Earth Sciences, vol. 18, Reports, vol. 5, no. 1, article 16824, 2015. no. 3, pp. 293–305, 2000. [28] X. Yu, C. T. A. Lee, L. H. Chen, and G. Zeng, “Magmatic fl [14] Y. Q. Li, C. Q. Ma, P. T. Robinson, Q. Zhou, and M. L. Liu, recharge in continental ood basalts: insights from the Chi- ” “Recycling of oceanic crust from a stagnant slab in the mantle feng igneous province in Inner Mongolia, Geochemistry, – transition zone: evidence from Cenozoic continental basalts Geophysics, Geosystems, vol. 16, no. 7, pp. 2082 2096, 2015. in Zhejiang Province, SE China,” Lithos, vol. 230, pp. 146– [29] P. Guo, Y. Niu, L. Ye et al., “Lithosphere thinning beneath 165, 2015. west North China Craton: Evidence from geochemical and ” [15] R. X. Liu, W. J. Chen, J. Z. Sun, and D. M. Li, “The K–Ar age Sr-Nd-Hf isotope compositions of Jining basalts, Lithos, – and tectonic environment of Cenozoic volcanic rocks in vol. 202-203, pp. 37 54, 2014. China,” in The Age and Geochemistry of Cenozoic Volcanic [30] Y. L. Niu, “Generation and evolution of basaltic magmas: Rock in China, R. X. Liu, Ed., pp. 1–43, Seismology Publ, Bei- some basic concepts and a new view on the origin of Meso- jing, 1992. zoic–Cenozoic basaltic volcanism in eastern China,” Geologi- – [16] K. Tu, M. F. J. Flower, R. W. Carlson, G. H. Xie, C. Y. Chen, cal Journal of China Universities, vol. 11, pp. 9 46, 2005. and M. Zhang, “Magmatism in the South China Basin: 1. Iso- [31] J. Charvet, H. Lapierre, and Y. W. Yu, “Geodynamic signifi- topic and trace-element evidence for an endogenous Dupal cance of the Mesozoic volcanism of southeastern China,” mantle component,” Chemical Geology, vol. 97, no. 1-2, Journal of Southeast Asian Earth Sciences, vol. 9, no. 4, pp. 47–63, 1992. pp. 387–396, 1994.

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 19

[32] K. J. Hsü, J. L. Li, H. H. Chen, Q. C. Wang, S. Sun, and A. M. magmas and for residual melts with melilite,” Mineralogy C. Sengör, “Tectonics of South China: key to understanding and Petrology, vol. 56, no. 3-4, pp. 225–250, 1996. fi ” West Paci c geology, Tectonophysics, vol. 183, no. 1-4, [47] Z. X. Dong and J. X. Zhou, “The typomorphic characteristics – pp. 9 39, 1990. of chromites from kimberlites in China and the significance [33] M. A. Menzies, W. M. Fan, and M. Zhang, “Palaeozoic and in exploration of diamond deposits,” Acta Geologica Sinica, Cenozoic lithoprobe and the loss of 120km of Archean lith- vol. 4, pp. 284–299, 1980. ” osphere, Sino Korean craton, China, in Magmatic Processes [48] C. Q. Wang, X. R. Du, and J. X. Liu, “Keluo–Wudalianchi– and Plate Tectonics, H. M. Prichard,> T. Alabaster, N. B. W. Erkeshan volcanic group. Chapter 7: mineral chemistry of Harris, and C. R. Neary, Eds., vol. 76 of Geological Society, the basanite,” Journal of East China University of Science – London, Special Publications: Home, pp. 71 81, 1993. and Technology, vol. 2, pp. 97–112, 1987. “ [34] X. M. Zhou and W. X. Li, Origin of Late Mesozoic igneous [49] D. A. Ionov, S. Y. O'Reilly, Y. S. Genshaft, and M. G. Kopy- rocks in Southeastern China: implications for lithosphere lova, “Carbonate-bearing mantle peridotite xenoliths from subduction and underplating of mafic magmas,” Tectonophy- Spitsbergen: phase relationships, mineral compositions and sics, vol. 326, no. 3-4, pp. 269–287, 2000. trace-element residence,” Contributions to Mineralogy and [35] P. Sun, Y. L. Niu, P. Y. Guo, L. Ye, J. J. Liu, and Y. X. Feng, Petrology, vol. 125, no. 4, pp. 375–392, 1996. “ Elemental and Sr-Nd-Pb isotope geochemistry of the Ceno- [50] J. R. Goldsmith, D. L. Graf, J. Witters, and D. A. Northrop, zoic basalts in Southeast China: Insights into their mantle “Studies in the system CaCO –MgCO –FeCO3: 1. Phase ” 3 3 sources and melting processes, Lithos, vol. 272-273, relations; 2. A method for major-element spectrochemical – pp. 16 30, 2017. analysis; 3. Compositions of some ferroan dolomites,” Jour- [36] Z. D. Li, H. Quan, Z. T. Li et al., Mesozoic to Neozoic igneous nal of Geology, vol. 70, no. 6, pp. 659–688, 1962. rocks and their deep processes, Geological Press, 2003. [51] M. Radivojević, M. Toljić, S. M. Turki, Z. Bojić,K.Šarić, and [37] X. Pan, Z. Hou, M. Zhao et al., “Geochronology and geo- V. Cvetković, “Neogene to quaternary basalts of the Jabal chemistry of the granites from the Zhuxi W-Cu ore deposit Eghei (Nuqay) area (south Libya): two distinct volcanic in South China: Implication for petrogenesis, geodynamical events or continuous volcanism with gradual shift in magma setting and mineralization,” Lithos, vol. 304-307, pp. 155– composition?,” Journal of Volcanology and Geothermal 179, 2018. Research, vol. 293, pp. 57–74, 2015. [38] J. Oshika, Y. Arakawa, D. Endo, T. Shinmura, and Y. Mori, [52] R. E. Harmer, C. A. Lee, and B. M. Eglington, “A deep mantle “A rare basanite distribution in the northern part of the source for carbonatite magmatism: evidence from the nephe- Izu-Bonin volcanic arc, Japan: petrological and geochemical linites and carbonatites of the Buhera district, SE Zimbabwe,” constraints,” Journal of volcanology and geothermal research, Earth and Planetary Science Letters, vol. 158, no. 3-4, pp. 131– vol. 270, pp. 76–89, 2014. 142, 1998. [39] G. Zeng, L. H. Chen, X. S. Xu, S. Y. Jiang, and A. W. Hof- [53] R. Halama, T. Vennemann, W. Siebel, and G. Markl, “The mann, “Carbonated mantle sources for Cenozoic intra-plate Grønnedal-Ika carbonatite–syenite complex, South Green- alkaline basalts in Shandong, North China,” Chemical Geol- land: carbonatite formation by liquid immiscibility,” Journal ogy, vol. 273, no. 1-2, pp. 35–45, 2010. of Petrology, vol. 46, no. 1, pp. 191–217, 2005. [40] R. Steiger and E. Jäger, “Subcommission on geochronology: [54] Y. X. Xue and Y. F. Zhu, “Genesis of the siderite in Jurassic convention on the use of decay constants in geo- and cosmo- olivine basalt, Karamay, Xinjiang, Northwest China,” Acta chronology,” Earth and Planetary Science Letters, vol. 36, Petrologica Sinica, vol. 23, pp. 1108–1122, 2007. – no. 3, pp. 359 362, 1977. [55] W. A. Dollase and W. M. Thomas, “The crystal chemistry [41] K. Ludwig, Isoplot/Ex, version 3.0: a geochronological tool kit of silica-rich alkali-deficient nepheline,” Contributions to for Microsoft Excel, vol. 43, Berkeley Geochronology Center Mineralogy and Petrology, vol. 66, no. 3, pp. 311–318, Special Publication, Berkeley, 2001. 1978. [42] M. Matusiak-Malek, J. Puziewicz, T. Ntaflos, M. Gregoire, [56] N. Li, L. Y. Zhang, Y. W. Zhao, Y. Y. Cao, and X. D. Pan, A. Kukula, and P. M. Wojtulek, “Origin and evolution of rare “Genesis of potassic minerals in the Xiaogulihe–Keluo– amphibole-bearing mantle peridotites from Wilcza Gora Wudalianchi–Erkeshan volcanic rock belt, Northeast China (SW Poland), Central Europe,” Lithos, vol. 286–287, and their geological implications,” Acta Petrologica Sinica, pp. 302–323, 2017. vol. 28, no. 4, pp. 1173–1180, 2012. [43] S. Arai, “Characterization of spinel peridotites by olivine–spi- [57] C. S. Liu, X. M. Chen, R. C. Wang, H. Hu, W. L. Zhang, and nel compositional relationships: review and interpretation,” M. Y. Lai, “Mineralogic characteristics and genesis for shilling Chemical Geology, vol. 113, no. 3-4, pp. 191–204, 1994. sodalite syenite, Nanling area, South China,” Acta Mineralo- – [44] X. Xu, S. Y. O’reilly, W. L. Griffin, and X. Zhou, “Genesis of gica Sinica, vol. 22, pp. 261 269, 2002. young lithospheric mantle in Southeastern China: an LAM– [58] L. Melluso, V. Morra, H. Riziky et al., “Petrogenesis of a ICPMS trace element study,” Journal of Petrology, vol. 41, basanite-tephrite-phonolite volcanic suite in the Bobaomby no. 1, pp. 111–148, 2000. (Cap d'Ambre) peninsula, northern Madagascar,” Journal of – [45] L. H. Chen, G. Zeng, S. L. Hu, X. Yu, and X. Y. Chen, “Crustal African Earth Sciences, vol. 49, no. 1-2, pp. 29 42, 2007. recycling and genesis of continental alkaline basalts: case [59] J. F. G. Wilkinson and H. D. Hensel, “Nephelines and anal- study of the Cenozoic alkaline basalts from Shandong Prov- cimes in some alkaline igneous rocks,” Contributions to Min- ince, Eastern China,” Journal of China University of Geos- eralogy and Petrology, vol. 118, pp. 79–91, 1994. – ciences, vol. 18, pp. 6 27, 2012. [60] A. K. Gupta, S. Chattopadhyay, B. Chattopadhyay, and [46] L. Melluso, V. Morra, and P. di Girolamo, “The Mt. Vulture M. Arima, “Experimental study of the system diopside- volcanic complex (Italy): evidence for distinct parental nepheline-sanidine at 0.1, 1 and 2 GPa [P (H2O) = P (Total)]:

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 20 LITHOSPHERE

Its significance in the genesis of alkali-rich basic and ultraba- beneath Ross Island, Antarctica,” Journal of Petrology, sic rocks,” Lithos, vol. 86, no. 1-2, pp. 91–109, 2006. vol. 57, no. 1, pp. 93–118, 2016. [61] C. M. B. Henderson and F. G. F. Gibb, “Felsic mineral crystal- [75] R. Dasgupta, M. M. Hirschmann, and N. D. Smith, “Partial ff ” lization trends in di erentiating alkaline basic magmas, melting experiments of peridotite + CO2 at 3 GPa and genesis Contributions to Mineralogy and Petrology, vol. 84, no. 4, of alkalic ocean island basalts,” Journal of Petrology, vol. 48, pp. 355–364, 1983. no. 11, pp. 2093–2124, 2007. [62] J. Dostal, J. G. Shellnutt, and J. Ulrych, “Petrogenesis of the [76] A. Gómez-Ulla, O. Sigmarsson, and G. H. Gudfinnsson, Cenozoic alkaline volcanic rock series of the České Středohoří “Trace element systematics of olivine from historical erup- Complex (Bohemian Massif), Czech Republic: a case for two tions of Lanzarote, Canary Islands: constraints on mantle lineages,” American Journal of Science, vol. 317, no. 6, source and melting mode,” Chemical Geology, vol. 449, pp. 677–706, 2017. pp. 99–111, 2017. [63] J. Reyes, L. E. Lara, and D. Morata, “Contrasting P-T paths [77] D. R. Smith, J. Noblett, R. A. Wobus, D. Unruh, and of shield and rejuvenated volcanism at Robinson Crusoe K. Chamberlain, “A review of the Pikes Peak batholith, Front Island, Juan Fernandez Ridge, SE Pacific,” Journal of Vol- Range, central Colorado: a “type example” of A-type granitic canology and Geothermal Research, vol. 341, pp. 242–254, magmatism,” Rocky Mountain Geology, vol. 34, pp. 93–116, 2017. 1999. [64] S. Tappe, K. A. Smart, A. Stracke, R. L. Romer, D. Prelevic, [78] D. J. DePaolo and E. E. Daley, “Neodymium isotopes in and P. van den Bogaard, “Melt evolution beneath a rifted cra- basalts of the southwest basin and range and lithospheric ton edge: 40Ar/39Ar geochronology and Sr-Nd- Hf-Pb isotope thinning during continental extension,” Chemical Geology, systematics of primitive alkaline basalts and lamprophyres vol. 169, no. 1-2, pp. 157–185, 2000. ” from the SW Baltic Shield, Geochimica et Cosmochimica [79] R. N. Thompson and M. A. Morrison, “Asthenospheric and – Acta, vol. 173, pp. 1 36, 2016. lower-lithospheric mantle contributions to continental [65] A. Weit, R. B. Trumbull, J. K. Keiding, W. H. Geissler, S. A. extensional magmatism: an example from the British Tertiary Gibson, and I. V. Veksler, “The magmatic system beneath Province,” Chemical Geology, vol. 68, no. 1-2, pp. 1–15, 1988. the Tristan da Cunha Island: insights from thermobarometry, [80] S. Kürüm and Ö. Tanyıldızı, “Geochemical and Sr-Nd isoto- melting models and geophysics,” Tectonophysics, vol. 716, pic characteristics of Upper Cretaceous (calc- alkaline) and no. Special Issue, pp. 64–76, 2017. Miocene (alkaline) volcanic rocks: Elazığ, Eastern Taurides, [66] H. Zou and Q. Fan, “U-Th isotopes in Hainan basalts: impli- Turkey,” Journal of African Earth Sciences, vol. 134, cations for sub-asthenospheric origin of EM2 mantle end- pp. 332–344, 2017. member and the dynamics of melting beneath Hainan [81] E. Y. Ersoy, C. Helvacı, and M. R. Palmer, “Petrogenesis of Island,” Lithos, vol. 116, no. 1-2, pp. 145–152, 2010. the Neogene volcanic units in the NE–SW-trending basins [67] F. A. Frey and M. Prinz, “Ultramafic inclusions from San in western Anatolia, Turkey,” Contributions to Mineralogy Carlos, Arizona: petrologic and geochemical data bearing and Petrology, vol. 163, no. 3, pp. 379–401, 2012. on their petrogenesis,” Earth and Planetary Science Letters, [82] B. Kasapoglu, Y. E. Ersoy, I. Uysal et al., “The petrology of vol. 38, no. 1, pp. 129–176, 1978. Paleogene volcanism in the Central Sakarya, Nallıhan Region: [68] S. S. Sun and W. F. McDonough, “Chemical and isotopic sys- Implications for the initiation and evolution of post-colli- tematics of oceanic basalts: implications for mantle composi- sional, slab break- off-related magmatic activity,” Lithos, tion and processes,” Geological Society, London, Special vol. 246-247, pp. 81–98, 2016. – Publications, vol. 42, no. 1, pp. 313 345, 1989. [83] M. Faure, Y. Sun, L. Shu, P. Monié, and J. Charvet, “Exten- [69] C. Cucciniello, L. Melluso, A. P. le Roex et al., “From olivine sional tectonics within a subduction-type orogen. The case nephelinite, basanite and basalt to peralkaline trachyphono- study of the Wugongshan dome (Jiangxi Province, southeast- lite and comendite in the Ankaratra volcanic complex, Mad- ern China),” Tectonophysics, vol. 263, no. 1-4, pp. 77–106, agascar: 40Ar/39Ar ages, phase compositions and bulk-rock 1996. geochemical and isotopic evolution,” Lithos, vol. 274-275, [84] J. Yan, Y. J. An, and J. F. Chen, “Isotopic characteristics of the pp. 363–382, 2017. Mesozoic to Cenozoic basic rocks from eastern China: char- [70] L. Q. Xia, Z. C. Xia, and X. Y. Xu, “Origin and evolution of acter of magmatic source and deep processes,” Geological middle-pleistocene basanitic magmas from Nüshan, China,” Review, vol. 57, pp. 532–540, 2011. Acta Petrologica Sinica, vol. 10, pp. 223–235, 1994. [85] J. J. Zhang, Y. F. Zheng, and Z. F. Zhao, “Geochemical evi- [71] X. C. Zhi, D. G. Chen, Z. Q. Zhang, and J. H. Wang, “The dence for interaction between oceanic crust and lithospheric neodymium and strotium isotopic composiions of Cenozoic mantle in the origin of Cenozoic continental basalts in east- alkalic basalts from Penglai and Lingqu, Shandong Province,” central China,” Lithos, vol. 110, no. 1-4, pp. 305–326, 2009. Geological Review, vol. 40, pp. 526–533, 1994. [86] X. C. Zhi and X. Qin, “Re–Os isotope geochemistry of [72] X. C. Zhi and D. G. Chen, “Neodymium and strostium isoto- mantle-derived peridotite xenoliths from eastern China: con- pic compositions for later tertiary alkalic basalts from Liuhe– straints on the age and thinning of lithosphere mantle,” Acta Yizheng, Jiangsu Province, China,” Acta Petrologica Sinica, Petrolgica Sinica, vol. 20, pp. 989–998, 2004. vol. 10, pp. 382–389, 1994. [87] S. P. Qian, Z. R. Ren, Y. H. Zhang et al., “Mantle source char- [73] K. Putirka, “Thermometers and barometers for volcanic sys- acteristics of Cenozoic basalts in eastern China,” Geotectonica tems,” Reviews in Mineralogy and Geochemistry, vol. 69, et Metallogenia, vol. 39, pp. 1119–1140, 2015, (In Chinese no. 1, pp. 61–120, 2008. with English abstract). [74] K. Iacovino, C. Oppenheimer, B. Scaille, and P. Kyle, “Storage [88] L. H. Chen, G. Zeng, S. Y. Jiang, A. W. Hofmann, X. S. Xu, and evolution of mafic and intermediate alkaline magmas and M. B. Pan, “Sources of Anfengshan basalts: subducted

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 LITHOSPHERE 21

lower crust in the Sulu UHP belt, China,” Earth and Plane- [102] K. Hirose, “Partial melt compositions of carbonated perido- tary Science Letters, vol. 286, no. 3-4, pp. 426–435, 2009. tite at 3 GPa and role of CO2in alkali-basalt magma genera- ” [89] Q. C. Fan, J. L. Sui, P. Xu, N. Li, Q. Sun, and T. H. Wang, “Si- tion, Geophysical Research Letters, vol. 24, no. 22, – rich and alkaline-rich melting inclusions in mantle pyrolite in pp. 2837 2840, 1997. eastern China and their implication to the lithospheric evolu- [103] Q. C. Fan, R. X. Liu, P. Xu, and Z. R. Lin, “Intermediate-acidic tion,” Science in China Series D-Earth Sciences, vol. 35, silicate melt existed in continental mantle of eastern China,” pp. 907–913, 2005. Chinese Science Bulletin, vol. 16, pp. 1535-1536, 1996. [90] Q. C. Fan, R. X. Liu, Z. R. Lin, X. L. Chu, R. Zhao, and W. G. [104] A. Golovin and V. Sharygin, “Petrogenetic analysis of fluid Huo, “Preliminary study of carbon isotope in mantle CO2 and melt inclusions in minerals from mantle xenoliths from fluid inclusion from eastern China,” Geochimica, vol. 25, the Bele pipe basanites (North Minusa depression),” Russian pp. 264–269, 1996. Geology and Geophysics, vol. 48, no. 10, pp. 811–824, 2007. [91] R. X. Liu, Q. C. Fan, Z. R. Lin, J. M. Yuan, and J. G. Sun, “Dis- [105] Y. J. Liu, Z. L. Li, Q. Z. Wu, M. F. Zhao, and H. S. Jiang, “Melt- covery of polyphase solid fillers in mantle fluid inclusions and ing inclusion study of minerals in some basalts from eastern its significance,” Chinese Science Bulletin, vol. 18, pp. 2177– China,” Geochimica, vol. 3, pp. 216–226, 1985. 2180, 1993. [106] M. J. Zhang, X. B. Wang, G. Liu, Q. B. Wen, and L. W. Li, [92] L. G. Peng, R. X. Liu, and Q. C. Fan, “Fluid and melt inclusion “The fluid compositions and C, O isotopic geochemistry of researches of pyrolite xenoliths from the shore of southeast- Cenozoic alkali basalts in eastern China,” Geochimica, ern China,” Acta Petrologica Sinica, vol. 10, pp. 440–448, vol. 27, pp. 452–457, 1998. 1994. [107] D. R. Nelson, A. R. Chivas, B. W. Chappell, and M. T. McCul- [93] R. Dasgupta, M. M. Hirschmann, W. F. McDonough, loch, “Geochemical and isotopic systematics in carbonatites M. Spiegelman, and A. C. Withers, “Trace element partition- and implications for the evolution of ocean-island sources,” ing between garnet lherzolite and carbonatite at 6.6 and 8.6 Geochimica et Cosmochimica Acta, vol. 52, no. 1, pp. 1–17, GPa with applications to the geochemistry of the mantle 1988. and of mantle- derived melts,” Chemical Geology, vol. 262, [108] W. J. Lee and P. J. Wyllie, “Petrogenesis of carbonatite no. 1-2, pp. 57–77, 2009. magmas from mantle to crust constrained by the system – – – – [94] S. F. Foley, M. G. Barth, and G. A. Jenner, “Rutile/melt parti- CaO (MgO + FeO) (Na2O+ K2O) (SiO2+Al2O3+TiO2) ” – tion coefficients for trace elements and an assessment of the CO2, Journal of Petrology, vol. 39, no. 3, pp. 495 517, 1998. influence of rutile on the trace element characteristics of sub- [109] W. J. Lee and P. J. Wyllie, “Processes of crustal carbonatite duction zone magmas,” Geochimica et Cosmochimica Acta, formation by liquid immiscibility and differentiation, eluci- vol. 64, no. 5, pp. 933–938, 2000. dated by model systems,” Journal of Petrology, vol. 39, [95] R. L. Linnen and H. Keppler, “Melt composition control of no. 11-12, pp. 2005–2013, 1998. Zr/Hf fractionation in magmatic processes,” Geochimica et [110] W. G. Minarik, “Complications to carbonate melt mobility Cosmochimica Acta, vol. 66, no. 18, pp. 3293–3301, 2002. due to the presence of an immiscible silicate melt,” Journal – [96] S. Klemme, J. D. Blundy, and B. J. Wood, “Experimental con- of Petrology, vol. 39, no. 11-12, pp. 1965 1973, 1998. straints on major and trace element partitioning during par- [111] S. S. Chen, Y. P. Su, J. P. Zheng, and Y. Wei, “Geochemical tial melting of eclogite,” Geochimica et Cosmochimica Acta, characteristics of Karamay Jurassic basalts and implication vol. 66, no. 17, pp. 3109–3123, 2002. on crust–mantle interaction,” Geochimica, vol. 42, pp. 29– [97] M. B. C. Coltorti, C. Bonadiman, R. W. Hinton, F. Siena, and 45, 2013. B. G. J. Upton, “Carbonatite metasomatism of the oceanic [112] J. LIU, H. F. Zhang, J. G. Sun, and J. Ye, “Geochemical upper mantle: evidence from clinopyroxenes and glasses in research on C—O and Sr—Nd isotopes of mantle-derived ultramafic xenoliths of Grande Comore, Indian Ocean,” Jour- rocks from Shandong Province, China,” Science in China nal of Petrology, vol. 40, no. 1, pp. 133–165, 1999. Series D: Earth Sciences, vol. 47, no. 2, pp. 171–180, 2004. [98] S. Klemme, S. R. van der Laan, S. F. Foley, and D. Gunther, [113] G. Zeng, L. H. Chen, A. W. Hofmann, S. Y. Jiang, and X. S. “Experimentally determined trace and minor element parti- Xu, “Crust recycling in the sources of two parallel volcanic tioning between clinopyroxene and carbonatite melt under chains in Shandong, North China,” Earth and Planetary Sci- upper mantle conditions,” Earth and Planetary Science Let- ence Letters, vol. 302, no. 3-4, pp. 359–368, 2011. ters, vol. 133, no. 3-4, pp. 439–448, 1995. [114] M. A. Menzies and P. R. Kyle, Continental volcanism: a crust– [99] R. L. Rudnick, W. F. McDonough, and B. W. Chappell, “Car- mantle probe, M. A. Menzies, Ed., Continental Mantle Clar- bonatite metasomatism in the northern Tanzanian mantle: endon Press, Oxford, 1990. petrographic and geochemical characteristics,” Earth and [115] D. McKenzie and R. K. O'Nions, “Partial melt distributions Planetary Science Letters, vol. 114, no. 4, pp. 463–475, 1993. from inversion of rare earth element concentrations,” Journal [100] L. Chmyz, N. Arnaud, J. C. Biondi, R. G. Azzone, D. Bosch, of Petrology, vol. 32, no. 5, pp. 1021–1091, 1991. and E. Ruberti, “Ar-Ar ages, Sr-Nd isotope geochemistry, [116] M. Pertermann, M. M. Hirschmann, K. Hametner, and implications for the origin of the silicate rocks of the D. Günther, and M. W. Schmidt, “Experimental determina- Jacupiranga ultramafic-alkaline complex (Brazil),” Journal tion of trace element partitioning between garnet and silica- of South American Earth Sciences, vol. 77, pp. 286–309, 2017. rich liquid during anhydrous partial melting of MORB-like [101] C. N. Ngwa, T. H. Hansteen, C. W. Devey, F. M. van der eclogite,” Geochemistry, Geophysics, Geosystems, vol. 5, Zwan, and C. E. Suh, “Origin and evolution of primitive melts no. 5, 2004. from the Debunscha Maar, Cameroon: consequences for [117] A. V. Sobolev, A. W. Hofmann, S. V. Sobolev, and I. K. Niko- mantle source heterogeneity within the Cameroon Volcanic gosian, “An olivine-free mantle source of Hawaiian shield Line,” Lithos, vol. 288-289, pp. 326–337, 2017. basalts,” Nature, vol. 434, no. 7033, pp. 590–597, 2005.

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021 22 LITHOSPHERE

[118] A. R. An, S. H. Choi, Y. Yu, and D. C. Lee, “Petrogenesis of Late Cenozoic basaltic rocks from southern Vietnam,” Lithos, vol. 272-273, pp. 192–204, 2017. [119] H. O. Choi, S. H. Choi, P. Schiano et al., “Geochemistry of olivine-hosted melt inclusions in the Baekdusan (Chang- baishan) basalts: implications for recycling of oceanic crustal materials into the mantle source,” Lithos, vol. 284-285, pp. 194–206, 2017. [120] F. Y. Wu and D. Y. Sun, “The Mesozoic magmatism and lithospheric thinning in eastern China,” Journal of Changchun University of Science and Technology, vol. 29, pp. 313–318, 1999. [121] S. Preb, G. Wirr, H. Seck, D. Eonov, and V. Kovalenko, “Spi- nel peridotite xenoliths from the Tariat Depression, Mongo- lia. I: Major element chemistry and mineralogy of a primitive mantle xenolith suite,” Geochimica et Cosmochi- mica Acta, vol. 50, no. 12, pp. 2587–2599, 1986. [122] A. R. Basu and I. D. MacGregor, “Chromite spinels from ultramafic xenoliths,” Chromium: its Physicochemical Behav- ior and Petrologic Significance, vol. 39, no. 6-7, pp. 937–945, 1975. [123] D. McKenzie and M. J. Bickle, “The volume and composition of melt generated by extension of the lithosphere,” Journal of Petrology, vol. 29, no. 3, pp. 625–679, 1988. [124] P. J. Wyllie and W. H. Huang, “Carbonation and melting – – – reactions in the system CaO MgO SiO2 CO2 at mantle pressures with geophysical and petrological applications,” Contributions to Mineralogy and Petrology, vol. 54, no. 2, pp. 79–107, 1976. [125] N. Morimoto, “Nomenclature of pyroxenes: subcommittee on pyroxenes, Commission on New Minerals and Mineral Names, International Mineralogical Association,” American Mineralogist, vol. 3, pp. 1123–1133, 1988. [126] R. W. Le Maitre, P. Bateman, A. Dudek et al., A Classification of Igneous Rocks and Glossary of Terms, Blackwell, Oxford, 1989. [127] W. F. McDonough and S.-S. Sun, “The composition of the Earth,” Chemical Geology, vol. 120, no. 3-4, pp. 223–253, 1995. [128] R. L. Rudnick and S. Gao, “Composition of the continental crust,” Treatise on Geochemistry, vol. 3, pp. 1–64, 2003.

Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2021/9732167/5292512/9732167.pdf by guest on 28 September 2021