DOCSLIB.ORG

Genesis of the Nanyangtian Scheelite Deposit in Southeastern Yunnan Province, China: Evidence from Mineral Chemistry, Fluid Incl

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Genesis of the Nanyangtian Scheelite Deposit in Southeastern Yunnan Province, China: Evidence from Mineral Chemistry, Fluid Incl Acta Geochim (2018) 37(4):614–631 https://doi.org/10.1007/s11631-017-0257-0 ORIGINAL ARTICLE Genesis of the Nanyangtian scheelite deposit in southeastern Yunnan Province, China: evidence from mineral chemistry, fluid inclusions, and C–O isotopes 1 1 1 1 1 Qianru Cai • Yongfeng Yan • Guangshu Yang • Fuju Jia • Chao Li Received: 19 April 2017 / Revised: 22 November 2017 / Accepted: 26 December 2017 / Published online: 16 January 2018 Ó Science Press, Institute of Geochemistry, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract The Nanyangtian skarn-type scheelite deposit is the formation of the Nanyangtian deposit is related to an important part of the Laojunshan W–Sn polymetallic Laojunshan granitic magmatism. metallogenic region in southeastern Yunnan Province, China. The deposit comprises multiple scheelite ore bodies; Keywords Fluid inclusion Á C–O isotopes Á Skarn Á multilayer skarn-type scheelite ore bodies are dominant, Scheelite deposit Á Nanyangtian with a small amount of quartz vein-type ore bodies. Skarn minerals include diopside, hedenbergite, grossular, and epidote. Three mineralization stages exist: skarn, quartz– 1 Introduction scheelite, and calcite. The homogenization temperatures of fluid inclusions in hydrothermal minerals that formed in The Laojunshan W–Sn metallogenic district is an impor- different paragenetic phases were measured as follows: tant mineral resource base in Yunnan Province. Various 221–423 °C (early skarn stage), 177–260 °C (quartz– W–Sn polymetallic deposits surround the Laojunshan scheelite stage), and 173–227 °C (late calcite stage). The granitic pluton: the Nanyangtian-Chayeshan W metallo- measured salinity of fluid inclusions ranged from 0.18% to genic belt in the east, the Dazhushan-Xinzhai Sn–W met- 16.34% NaCleqv (skarn stage), 0.35%–7.17% NaCleqv allogenic belt in the north, and the Manjiazhai-Tongjie Zn– (quartz–scheelite stage), and 0.35%–2.24% NaCleqv (late Sn–In metallogenic belt in the southwest. Ten years ago, a calcite vein stage). Laser Raman spectroscopic studies on large Nanyangtian scheelite deposit containing high-grade fluid inclusions in the three stages showed H2O as the main ore with considerable prospecting potential was discov- component, with N2 present in minor amounts. Minor ered; it has since been the subject of several studies. Pre- amounts of CH4 were found in the quartz–scheelite stage. It vious research has focused on the geological setting, was observed that the homogenization temperature gradu- geochemistry, and fluid inclusions of minerals in this ally reduced from the early to the late mineralization deposit and has produced a detailed chronology of events 13 stages; moreover, d CPDB values for ore-bearing skarn in (Zeng et al. 1999; Shi et al. 2011; Wang et al. 2012; Feng the mineralization period ranged from - 5.7% to - 6.9% et al. 2011a, b), thereby paving the way for further 18 and the corresponding d OSMOW values ranged from 5.8% prospecting. to 9.1%, implying that the ore-forming fluid was mainly Previous work in the field of fluid inclusions includes: sourced from magmatic water with a minor amount of Feng et al. (2011a, b) work on quartz and garnet in the meteoric water. Collectively, the evidence indicates that Nanyangtian scheelite deposit; Li (2013) research of fluid inclusions in quartz, garnet, and calcite in the Yanggouhe deposit; and Zhang et al.’s (2014) study of inclusions in skarn mineral and quartz in the Guanfang scheelite deposit & Yongfeng Yan using a thermometer and laser Raman spectrometer. Pre- [email protected] vious research on the source of ore-forming fluids and ore 1 Kunming University of Science and Technology, genesis by fluid inclusion analysis has not been compre- Kunming 650093, China hensive. As gangue minerals and ore minerals have 123 Acta Geochim (2018) 37(4):614–631 615 different characteristics, the condition of ore minerals The study area is in the southeastern Yunnan–western cannot be gleaned by analyzing gangue (Campbell and Guixi metallogenic belt, which lies to the west of the Robinson-Cock 1987; Campbell and Panter 1990; Gia- Nanling W–Sn polymetalloic metallogenic belt. Laojun- mello et al. 1992). All three publications mentioned above shan therefore experiences frequent geologic activity, focused on the characteristics of fluid inclusions in gangue contains many active faults, and has excellent metallogenic minerals rather than in ore; by analyzing fluid inclusions of conditions. ore minerals, the current work aims to provide more rele- Because of a lack of upper Ordovician, Silurian, Juras- vant information on the properties of metallogenic fluids. sic, and Cretaceous strata, other strata are fully exposed in Following a description of the geological setting and the area. According to lithology, the Laojunshan rock body lithology of the Nanyangtian scheelite deposit, we discuss can be divided into seven intrusive bodies: the Tuantian skarn mineralogical characteristics and the associated medium- to fine-grained granitic, Laochengpo fine-grained evolutionary process. Next, we report data from fluid granitic, Huashitou two-mica adamellite, Malutang med- inclusions in gangue and ore minerals, focusing particu- ium- to fine-grained two-mica adamellite, Taipingtou larly on the analysis of scheelite fluid inclusions. Finally, medium- to fine-grained two-mica adamellite, Qingjiao information about the ore-forming fluid and a logical micrograin two-mica adamellite, and Kouha granite-por- explanation of the genesis of the Nanyangtian skarn phyry intrusions. The Cambrian strata are exposed in the scheelite deposit are provided. external contact zone of the Laojunshan rock body, which is mainly composed of schist, plagioclasite hornblende 1.1 Regional geology schist, amphibolite, and carbonate. Under magmatic hydrothermalism, carbonate altered to stratiform skarn, in Laojunshan is located at the intersection of the peri-Pacific which the scheelite ore body occurs. and Tethyan Himalayan tectonic syntaxes and at the The Cambrian strata comprise the Chongzhuang For- junction of the South China fold system, Ailaoshan fold mation in the Lower Cambrian series ( 1” ch), and the ” system, North Vietnam Block, and Yangtze Plate (Fig. 1). Longha ( 2” l) and Tianpeng formations ( 2t) in the Middle Fig. 1 Schematic tectonic map (a) and regional geological map (b) (after Zijin Tungsten Industry Group Co. LTD 2014) 123 616 Acta Geochim (2018) 37(4):614–631 Cambrian series. The Chongzhuang Formation exists with direction of motion (from southeast to northwest). It is mainly in the Nanyangtian mining area and can be classi- thought that the nappe fault may have been formed by the fied into three lithologic members: the lower Geling section decoupling detachment of the Nanwenhe metamorphic ” 1 ( 1ch ), comprising granite gneiss and plagioclase gneiss; core complex. The Nanyangtian sliding fracture is the ” 2 the middle Nanyangtian Section ( 1ch ), comprising ver- highest sliding fracture within the nappe structure and is delite biotite granulite, biotite plagioclase gneiss, two-mica exposed to the east of the mining area near Nanyangtian. schist, and tremolite-zoisite-diopside skarn; and the upper The southwest section of the fault is intruded by Dulong ” 3 Taiyangping section ( 1ch ), comprising muscovite mon- super-unit granite; the upper wall of the fault relates to the zonitic gneiss. The Longha Formation is exposed mainly in Laochengpo intrusion and contains Nanwenhe sequence Wenshan and Maguan as a hoary-white medium-embedded gneissic fine-grained granite. The major fracture surface dolomite marble with a middle layer containing a small has strong mylonitization, and a quartz vein is sheared into amount of phyllite and a bottom layer containing mus- a ‘‘Z’’ fold and a rootless fold by the fault. The hanging covite schist. The Tianpeng Formation occurs exclusively wall mainly consists of schist within the Chongzhuang in the Dulong mining area. Its bottom layer is gneiss; its Formation, and the cleavage tendency is southeast. The middle layer contains ore-bearing rocks mainly comprising schist and gneiss have a small asymmetric fold plunging actinolite, diopside, and chlorited skarn; and the rocks in its toward 200°–220° at an angle of 8°–15°. upper stratum are dolomitic phyllite, mica quartz schist, The Yanshanian Laojunshan granitic pluton outcrops to and interbedded marble (Jia 2010). the east of the mining area. Local igneous activity exhibits The Wenshan-Malipo Fault lies to the north of the multiphase and multistage characteristics. Evolutionary Laojunshan granite body, the Maguan-Dulong Fault lies to periods (from ancient times to the current day) have the south, and the Nanwenhe Fault is an almost east–west resulted in three rock types: medium-coarse monzogranite, direction. The secondary fault of Laojunshan provides medium-fine monzogranite, and granite porphyry (the conditions suitable for W–Sn ore formation. Regional spread of which is reduced from the first rock body to the metamorphism is strong, owing to multistage tectonism. A third, with the late-stage rock body intruding into the early low-temperature regional dynamo metamorphism of gran- rock body). The main part of the outcropped bedrock in the ulite and schist occurred during the Caledonian-Indosinian. mining area is gneissic fine-grained granite porphyry with a In addition, contact metamorphism occurred with the mineral composition of 40% plagioclase, 40% quartz, and intrusion of Laojunshan granite during the Yanshanian, 10% biotite. The gneiss composition
Load more

Recommended publications
  • Structure and Physical Properties of Hydrogrossular Mineral Series
    STRUCTURE AND PHYSICAL PROPERTIES OF HYDROGROSSULAR MINERAL SERIES A THESIS IN PHYSICS Presented to the Faculty of the University of Missouri-Kansas City in Partial requirements for the degree MASTER OF SCIENCE By PUJA ADHIKARI M.Sc, Tribhuban University, Kathmandu, Nepal, 2010 Kansas City, Missouri 2015 ©2015 PUJA ADHIKARI ALL RIGHTS RESERVED Structure and physical properties of Hydrogrossular mineral series Puja Adhikari, Candidate for the Master of Science Degree University of Missouri-Kansas City, 2015 ABSTRACT The mineral hydrogrossular series (Ca3Al2(SiO4)3-x(OH) 4x; 0 ≤ x ≤ 3) are important water bearing minerals found in the upper and lower part of the Earth’s mantle. They are vital to the planet’s hydrosphere under different hydrothermal conditions. The composition and structure of this mineral series are important in geoscience and share many commonalities with cement and clay materials. Other than the end members of the series x = 0 (grossular) and x = 3 (katoite) which have a cubic garnet structure, the structure of the series is totally unknown. We used large-scale ab initio modeling to investigate the structures and properties for hydrogrossular series for x = 0, 0.5, 1, 1.5, 2, 2.5, 3. Results indicate that for x > 0 and x < 3, the structures are tetragonal. This shows that there is structural change related to the lowering of overall symmetry associated with the composition of SiO4 tetrahedra and AlO6 octahedra. Total Bond order also explains the reason behind the change in the compressibility of the series. The electronic structure, mechanical and optical properties of the hydrogrossular series are calculated and the results for grossular and katoite are in good agreement with the available experimental data.
    [Show full text]
  • A Review of Flotation Separation of Mg Carbonates (Dolomite and Magnesite)
    minerals Review A Review of Flotation Separation of Mg Carbonates (Dolomite and Magnesite) Darius G. Wonyen 1,†, Varney Kromah 1,†, Borbor Gibson 1,† ID , Solomon Nah 1,† and Saeed Chehreh Chelgani 1,2,* ID 1 Department of Geology and Mining Engineering, Faculty of Engineering, University of Liberia, P.O. Box 9020 Monrovia, Liberia; [email protected] (D.G.W.); [email protected] (Y.K.); [email protected] (B.G.); [email protected] (S.N.) 2 Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA * Correspondence: [email protected]; Tel.: +1-41-6830-9356 † These authors contributed equally to the study. Received: 24 July 2018; Accepted: 13 August 2018; Published: 15 August 2018 Abstract: It is well documented that flotation has high economic viability for the beneficiation of valuable minerals when their main ore bodies contain magnesium (Mg) carbonates such as dolomite and magnesite. Flotation separation of Mg carbonates from their associated valuable minerals (AVMs) presents several challenges, and Mg carbonates have high levels of adverse effects on separation efficiency. These complexities can be attributed to various reasons: Mg carbonates are naturally hydrophilic, soluble, and exhibit similar surface characteristics as their AVMs. This study presents a compilation of various parameters, including zeta potential, pH, particle size, reagents (collectors, depressant, and modifiers), and bio-flotation, which were examined in several investigations into separating Mg carbonates from their AVMs by froth flotation. Keywords: dolomite; magnesite; flotation; bio-flotation 1. Introduction Magnesium (Mg) carbonates (salt-type minerals) are typical gangue phases associated with several valuable minerals, and have complicated processing [1,2].
    [Show full text]
  • Overview of Tungsten Indicator Minerals Scheelite and Wolframite with Examples from the Sisson W-Mo Deposit, Canada
    Overview of tungsten indicator minerals scheelite and wolframite with examples from the Sisson W-Mo deposit, Canada M. Beth McClenaghan1, M.A. Parkhill2, A.A. Seaman3, A.G. Pronk3, M. McCurdy1 & D.J. Kontak4 1Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, Canada K1A 0E8 (e-mail: [email protected]) 2New Brunswick Department of Energy and Mines, Geological Surveys Branch, P.O. Box 50, Bathurst, New Brunswick, Canada E2A 3Z1 3New Brunswick Department of Energy and Mines, Geological Surveys Branch, P.O. Box 6000, Fredericton, New Brunswick, Canada E3B 5H1 4Department of Earth Sciences, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 These short course notes provide an overview of published lit- Table 1. List of regional surveys and case studies conducted around erature on the use of scheelite and wolframite as indicator min- the world in which scheelite and/or wolframite in surficial sediments erals for W, Mo, and Au exploration. The use of scheelite and have been used as indicator minerals. wolframite in stream sediments is well documented for mineral Mineral Media Location Source of Information exploration but less so for using glacial sediments (Table 1). scheelite stream sediments Pakistan Asrarullah (1982) wolframite stream sediments Burma ESCAP Scretariat (1982) The Geological Survey of Canada has recently conducted a scheelite, wolframite stream sediments USA Theobald & Thompson (1960) glacial till and stream sediment indicator mineral case study scheelite stream sediments, soil Thailand Silakul (1986) around the Sisson W-Mo deposit in eastern Canada. scheelite stream sediments Greenland Hallenstein et al. (1981) Preliminary indicator mineral results from this ongoing study scheelite stream sediments Spain Fernández-Turiel et al.
    [Show full text]
  • Geology of Tungsten Deposits in North-Central Chile
    UNITED STATES DEPARTMENT OF THE INTERIOR J. A. Krug, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director Bulletin 960-C GEOLOGY OF TUNGSTEN DEPOSITS IN NORTH-CENTRAL CHILE BY JAMES F. McALLISTER AND CARLOS RUIZ F. Prepared in cooperation with the DEPARTAMENTO DE MINAS Y PETROLED DE CHILE under the auspices of INTERDEPARTMENTAL COMMITTEE ON SCIENTIFIC AND CULTURAL COOPERATION, DEPARTMENT OF STATE Geologic Investigations in the American Republics, 1947 (Pages 89-108) UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1948 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C. Price $1.75 CONTENTS Page Abstract____..______________________________._ 89 Introduction___________________________-__________ __________-___ 89 Geology_________________________________..._ 92 Rocks.____________________________________ 92 Structure____________________________________ 92 Minerals. _.---_.----_..---_.------_- _- -- 92 Type, size, and grade of ore deposits.------------._-----_-_-_-_-_ 93 Descriptions of mining properties__________-___-_-_-_---__--_---____- 94 Salamanca region____________________________________________ 94 Castaneda de Llamuco mine--___----------_-------_------__ 94 Picbe prospect... ________.- _ . 97 Domeyko region_______________________________________________ 97 El Durazno district.-..__-___.___--_____-__________...___ 97 Boliviana mine-..._________-____-._--._._-__-_--__-__. 99 Minillas property......____________________________________ 99 Vallenar region______________________________________________ 101 San Antonio mining property.______________________________ 102 Zapallo de Chehuque mining property_________*____-______- 104 Metric equivalents____-____-_____-_______-----_-__--_-_-_-__--_-- 106 Index.--.___-____-_._______________._______________ 107 Page PLATE 21. Geologic map of the Castaneda de Llamuco tungsten deposit. In pocket 22. Plan of workings, Castafieda de Llamuco mine. _-____-___ In pocket 23.
    [Show full text]
  • Implications for Environmental and Economic Geology
    UNIVERSITY OF CALIFORNIA RIVERSIDE Kinetics of the Dissolution of Scheelite in Groundwater: Implications for Environmental and Economic Geology A Thesis submitted in partial satisfaction of the requirements for the degree of Master of Science in Geological Sciences by Stephanie Danielle Montgomery March 2013 Thesis Committee: Dr. Michael A. McKibben, Chairperson Dr. Christopher Amrhein Dr. Timothy Lyons Copyright by Stephanie Danielle Montgomery 2013 The Thesis of Stephanie Danielle Montgomery is approved: _________________________________________ _________________________________________ _________________________________________ Committee Chairperson University of California, Riverside ABSTRACT OF THE THESIS Kinetics of the Dissolution of Scheelite in Groundwater: Implications for Environmental and Economic geology by Stephanie Danielle Montgomery Masters of Science, Graduate Program in Geological Sciences University of California, Riverside, March 2013 Dr. Michael McKibben, Chairperson Tungsten, an emerging contaminant, has no EPA standard for its permissible levels in drinking water. At sites in California, Nevada, and Arizona there may be a correlation between elevated levels of tungsten in drinking water and clusters of childhood acute lymphocytic leukemia (ALL). Developing a better understanding of how tungsten is released from rocks into surface and groundwater is therefore of growing environmental interest. Knowledge of tungstate ore mineral weathering processes, particularly the rates of dissolution of scheelite (CaWO4) in groundwater, could improve models of how tungsten is released and transported in natural waters. Our research focused on the experimental determination of the rates and products of scheelite dissolution in 0.01 M NaCl (a proxy for groundwater), as a function of temperature, pH, and mineral surface area. Batch reactor experiments were conducted within constant temperature circulation baths over a pH range of 3-10.5.
    [Show full text]
  • Geology Club Mineral: Collecting Trip
    Geology Club: Mineral Collecting Trip (10 October 2009) Trip Notes by Charles Merguerian STOP 1 – Grossular Garnet Locality, West Redding, Connecticut. [UTM Coordinates: 630.71E / 4575.38N, Bethel quadrangle]. Covering roughly 60 acres of land, this enigmatic massive fine-grained grossularite garnet + diopside rock in West Redding has made many mineral collectors and geologists take notice. Walk up the steep slope east of Simpaug Turnpike to see highly fractured, massive cinnamon-colored grossular garnet rock, part of a 0.6-km wide heart-shaped mass found at the faulted contact between the Stockbridge Marble (OCs) and injected muscovitic schist of the Rowe Schist member (OCr) of the Hartland Formation (Figure 1). According to Rodgers et al. (1985), we are very near Cameron’s Line (red and black line in Figure 1). Figure 1 – Geologic map of the area surrounding Stop 1 showing the Proterozoic gneissic rocks (Yg) and Cambrian Dalton Schist (Cd) to the west, the Stockbridge Marble (OCs), Cameron’s Line (CL in red), the injected schistose rocks of the Rowe Formation (OCr), and an Ordovician granitoid (Og) that may be responsible for this unusual Ca++-enriched skarn deposit. Note the NW-trending high-angle brittle faults that cut the region. (Adapted from Rodgers et al. 1985.) Two knolls at this locality are almost entirely composed of grossularite garnet (var. essonite) and lesser clinopyroxene. Mostly the garnet occurs alone with minor quartz and localized quartz veining has been observed. Chemical analysis of the garnet (SiO2 = 39.10%, CaO = 34.85%, Al2O3 = 19.61%, and total FeO+Fe2O3 = 5.44%), are quite similar to published analyses of grossular garnet, including the phenomenal grossular garnet crystals from Morelos, Mexico.
    [Show full text]
  • Fluorian Garnets from the Host Rocks of the Skaergaard Intrusion: Implications for Metamorphic Fluid Composition
    American Mineralogist, Volume 75, pages 859-873,1990 Fluorian garnets from the host rocks of the Skaergaard intrusion: Implications for metamorphic fluid composition CRAIG E. MANNING, * DENNIS K. BIRD Department of Geology, Stanford University, Stanford, California 94305, U.S.A. ABSTRACT Zoned, silica-deficient, calcic garnets containing up to 5 mol% F substitution for 0 formed during contact metamorphism of basalts by the Skaergaard intrusion in East Greenland. Fluorian calcic garnets occur as a retrograde alteration of prograde wollastonite and clinopyroxene that fills vesicles and vugs in lavas 30-70 m from the intrusion. Para- genetically equivalent phases include fluorite, wollastonite, calcic clinopyroxene, prehnite, quartz, and calcite. Electron microprobe analysis shows that the garnets are :::-:93mol% grossular-andradite (grandite) solid solutions and that the F content does not fully com- pensate for the silica deficiency, suggesting the presence of a hydrous component in the garnets. The garnets display discontinuous zoning with respect to Al and Fe, and increases in F, calculated OH, and the Si deficiency with increasing Al concentration are observed. The garnets formed at temperatures between 200 and 420°C based on the coexisting mineral assemblage, and stratigraphic reconstructions indicate pressures of ~ 1 kbar. Assessment of isobaric, isothermal phase relations in the system CaO-A1203-Si02-H20- HF allows estimation of fluid characteristics in equilibrium with fluorian grandite-bearing assemblages. The presence of fluorite, wollastonite, quartz, and calcite with these garnets combined with fluid inclusion data require that the activity (a) of H20 was ~ 1 and that aH.aF was 10-105 to 10-10.0in the coexisting hydrothermal solutions at 200-420 °C and 1 kbar.
    [Show full text]
  • The Effect of Reduced Activity of Anorthite on the Reaction Grossular
    AmericanMineralogist, Volume61, pages 889-896,1976 The effectof reducedactivity of anorthiteon thereaction grossular * quartz : anorthite* wollastonite:a modelfor plagioclasein the earth'slower crust anh upper mantle K. E. WrNnoMr AND A. L. BoerrcHrnl Department of Geosciences,The Pennsyluania State (lniuersity Uniuersity Park, Pennsyluania 16802 Abstract The reaction CasAlrSiaor, + SiO, : CaAlzSiros + 2 CaSiOg (erossular) (quartz) (anortbite) (wollastoDite) wasinvestigated at l10ooC,using intermediate-composition plagioclase to determinethe shift of the equilibriumpressure as a functionof compositionat pressureand temperaturecondi- tions representativeof the earth'slower crustand uppermantle. For compositionswithin the rangeAnro-,00, activity of the anorthitecomponent is equalto its molefraction. For composi- tions more albitic than about Anro,the activity of the anorthitecomponent equals its mole fractionmultiplied by a constantfactor of 1.2.This latter behavioris interpretedas a resultof anorthite-likedomains being in an energeticallyunfavorable environment for thesecomposi- tions. Applicationof the data obtainedfrom subsolidusexperiments to meltingbehavior indicates that plagioclaseliquids do not obey Raoult'sLaw, but havean activitycoefficient similar to crystallineplagioclase. This hypothesisis supportedby high-pressuremelting experiments for both anhydrousand hydroussystems. In parts of the lower crustcomposed of basicrock (e.g.gabbro), the calcicplagioclase will be consumedat relativelyshallow levels and over a narrow (2-3 km)
    [Show full text]
  • The Journal of Gemmology Editor: Dr R.R
    he Journa TGemmolog Volume 25 No. 8 October 1997 The Gemmological Association and Gem Testing Laboratory of Great Britain Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street, London Eel N SSU Tel: 0171 404 1134 Fax: 0171 404 8843 e-mail: [email protected] Website: www.gagtl.ac.uklgagtl President: Professor R.A. Howie Vice-Presidents: LM. Bruton, Af'. ram, D.C. Kent, R.K. Mitchell Honorary Fellows: R.A. Howie, R.T. Liddicoat Inr, K. Nassau Honorary Life Members: D.). Callaghan, LA. lobbins, H. Tillander Council of Management: C.R. Cavey, T.]. Davidson, N.W. Decks, R.R. Harding, I. Thomson, V.P. Watson Members' Council: Aj. Allnutt, P. Dwyer-Hickey, R. fuller, l. Greatwood. B. jackson, J. Kessler, j. Monnickendam, L. Music, l.B. Nelson, P.G. Read, R. Shepherd, C.H. VVinter Branch Chairmen: Midlands - C.M. Green, North West - I. Knight, Scottish - B. jackson Examiners: A.j. Allnutt, M.Sc., Ph.D., leA, S.M. Anderson, B.Se. (Hons), I-CA, L. Bartlett, 13.Se, .'vI.phil., I-G/\' DCi\, E.M. Bruton, FGA, DC/\, c.~. Cavey, FGA, S. Coelho, B.Se, I-G,\' DGt\, Prof. A.T. Collins, B.Sc, Ph.D, A.G. Good, FGA, f1GA, Cj.E. Halt B.Sc. (Hons), FGr\, G.M. Howe, FG,'\, oo-, G.H. jones, B.Se, PhD., FCA, M. Newton, B.Se, D.PhiL, H.L. Plumb, B.Sc., ICA, DCA, R.D. Ross, B.5e, I-GA, DGA, P..A.. Sadler, 13.5c., IGA, DCA, E. Stern, I'GA, DC/\, Prof. I.
    [Show full text]
  • Solubility of Grossular, Ca3al2si3o12, in H2O–Nacl
    Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 71 (2007) 5191–5202 www.elsevier.com/locate/gca Solubility of grossular, Ca3Al2Si3O12,inH2O–NaCl solutions at 800 °C and 10 kbar, and the stability of garnet in the system CaSiO3–Al2O3–H2O–NaCl Robert C. Newton, Craig E. Manning * Department of Earth and Space Sciences, University of California Los Angeles, Los Angeles, CA 90095-1567, USA Received 8 February 2007; accepted in revised form 16 August 2007; available online 19 September 2007 Abstract The solubility and stability of synthetic grossular were determined at 800 °C and 10 kbar in NaCl–H2O solutions over a large range of salinity. The measurements were made by evaluating the weight losses of grossular, corundum, and wollastonite crystals equilibrated with fluid for up to one week in Pt capsules and a piston-cylinder apparatus. Grossular dissolves con- gruently over the entire salinity range and displays a large solubility increase of 0.0053 to 0.132 molal Ca3Al2Si3O12 with increasing NaCl mole fraction (XNaCl) from 0 to 0.4. There is thus a solubility enhancement 25 times the pure H2O value over the investigated range, indicating strong solute interaction with NaCl. The Ca3Al2Si3O12 mole fraction versus NaCl mole frac- tion curve has a broad plateau between XNaCl = 0.2 and 0.4, indicating that the solute products are hydrous; the enhancement effect of NaCl interaction is eventually overtaken by the destabilizing effect of lowering H2O activity. In this respect, the sol- ubility behavior of grossular in NaCl solutions is similar to that of corundum and wollastonite.
    [Show full text]
  • Nomenclature of the Garnet Supergroup
    American Mineralogist, Volume 98, pages 785–811, 2013 IMA REPORT Nomenclature of the garnet supergroup EDWARD S. GREW,1,* ANDREW J. LOCOCK,2 STUART J. MILLS,3,† IRINA O. GALUSKINA,4 EVGENY V. GALUSKIN,4 AND ULF HÅLENIUS5 1School of Earth and Climate Sciences, University of Maine, Orono, Maine 04469, U.S.A. 2Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada 3Geosciences, Museum Victoria, GPO Box 666, Melbourne 3001, Victoria, Australia 4Faculty of Earth Sciences, Department of Geochemistry, Mineralogy and Petrography, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland 5Swedish Museum of Natural History, Department of Mineralogy, P.O. Box 50 007, 104 05 Stockholm, Sweden ABSTRACT The garnet supergroup includes all minerals isostructural with garnet regardless of what elements occupy the four atomic sites, i.e., the supergroup includes several chemical classes. There are pres- ently 32 approved species, with an additional 5 possible species needing further study to be approved. The general formula for the garnet supergroup minerals is {X3}[Y2](Z3)ϕ12, where X, Y, and Z refer to dodecahedral, octahedral, and tetrahedral sites, respectively, and ϕ is O, OH, or F. Most garnets are cubic, space group Ia3d (no. 230), but two OH-bearing species (henritermierite and holtstamite) have tetragonal symmetry, space group, I41/acd (no. 142), and their X, Z, and ϕ sites are split into more symmetrically unique atomic positions. Total charge at the Z site and symmetry are criteria for distinguishing groups, whereas the dominant-constituent and dominant-valency rules are critical in identifying species. Twenty-nine species belong to one of five groups: the tetragonal henritermierite group and the isometric bitikleite, schorlomite, garnet, and berzeliite groups with a total charge at Z of 8 (silicate), 9 (oxide), 10 (silicate), 12 (silicate), and 15 (vanadate, arsenate), respectively.
    [Show full text]
  • Role of Sodium Carbonate in Scheelite Flotation – a Multi-Faceted Reagent
    Helmholtz-Zentrum Dresden-Rossendorf (HZDR) Role of sodium carbonate in scheelite flotation – a multi-faceted reagent Kupka, N.; Rudolph, M.; Originally published: October 2018 Minerals Engineering 129(2018), 120-128 DOI: https://doi.org/10.1016/j.mineng.2018.09.005 Perma-Link to Publication Repository of HZDR: https://www.hzdr.de/publications/Publ-27114 Release of the secondary publication on the basis of the German Copyright Law § 38 Section 4. CC-BY-NC-ND 4.0 *Manuscript Click here to view linked References Role of sodium carbonate in scheelite flotation – a multi-faceted reagent 1 1,a 1 2 Nathalie Kupka ; Martin Rudolph 3 1 Helmholtz Institute Freiberg for Resource Technology, Helmholtz Zentrum Dresden-Rossendorf, Chemnitzer 4 Straße 40, 09599 Freiberg, Germany 5 a 6 [email protected] 7 8 Abstract 9 10 Even though sodium carbonate is a reagent frequently used in flotation, its role is mostly described as 11 a buffering pH modifier and a pulp dispersant. In the case of scheelite flotation, it has been hinted that 12 13 sodium carbonate improves both grade and/or recovery but the mechanism itself is ambiguous at best 14 or at least has not been distinctly reported in the literature. Furthermore, the addition of depressants 15 such as sodium silicate or quebracho could be triggering additional mechanisms. Through batch 16 flotation testwork on a skarn scheelite ore with high calcite content, single mineral flotation and 17 contact angle measurements, this article aims at demonstrating that sodium carbonate is a multi- 18 faceted reagent, which serves as a buffering pH modifier, a pulp dispersant precipitating calcium and 19 20 magnesium ions in suspension, a depressant for calcite and calcium silicates and also a promoter for 21 scheelite.
    [Show full text]