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Halogen-rich scapolite-biotite rocks from the Tongmugou Pb-Zn deposit, Qinling, northwestern China: implications for the ore-forming processes

Published online by Cambridge University Press:  05 July 2018

Shao-Yong Jiang ,
M. R. Palmer ,
Chun-Ji Xue  and
Yan-He Li
Shao-Yong Jiang
Affiliation:
Department of Geology, University of Bristol, Bristol, BS8 1 RJ, U.K.
M. R. Palmer
Affiliation:
Department of Geology, University of Bristol, Bristol, BS8 1 RJ, U.K.
Chun-Ji Xue
Affiliation:
Xi’an College of Geology, Xi’an, 710054, China
Yan-He Li
Affiliation:
Institute of Mineral Deposits, Beijing, 100037, China
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Abstract

Coexisting scapolite, biotite and hornblende in scapolite-biotite rocks from the Tongmugou Pb-Zn deposit, Qinling, northwestern China are characterized by high levels of chlorine. Scapolite composition varies from EqAn27 to EqAn47 with 47–80 wt.% Cl. The scapolite composition is a sensitive indicator of the NaCl activity in coexisting hydrothermal fluid. Biotite contains 0.3–1.2 wt. % Cl and also has high F contents (0.2–0.7 wt.%). The hornblende is a Cl-rich hastingsite with Cl>3.5 wt.% and high (Na2O + K2O) contents (3.2–3.9 wt. %), high Xk [= K/(K + Na)] values (0.45–0.55) and high XFc [= Fe/(Fe + Mg)] values (0.76–0.79). The chlorine within these minerals is thought to be derived from evolved seawater. The scapolite-biotite rocks are products of Cl-rich alteration of volcanoclastic sedimentary rocks during submarine hydrothermal processes. Multiple-stage hydrothermal activity culminated with the circulation of a high-NaCl fluid that was also responsible for the formation of the massive sulphide deposits.

Keywords

halogensscapolite-biotite rockhydrothermal fluidsChinaPb-Zn deposits
Type
Petrology and Geochemistry
Information
Mineralogical Magazine , Volume 58 , Issue 393 , December 1994 , pp. 543 - 552
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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References

Chou, I-Ming and Eugster, H. P. (1977) Solubility of magnetite in supercritical chloride solutions. Amer. J. Set, 277, 1296–1314.Google Scholar
Dick, L. A. and Robinson, G. W. (1979) Chlorine-bearing potassian hastingsite from a sphalerite skarn in Southern Yukon. Canad. Mineral., 17, 25–6.Google Scholar
Ekstrom, T. K. (1972) The distribution of fluorine among some coexisting minerals. Contrib. Mineral. Petrol., 34, 192–200.CrossRefGoogle Scholar
Evans, B. W., Shaw, D. M. and Haughton, D. R.(1969) Scapolite stoichiometry. Contrib. Mineral. Petrol., 1A, 293-305.CrossRefGoogle Scholar
Grotzinger, J. P. (1986) Shallowing-upward cycles of the Wallace Formation, Belt Supergroup, north-western Montana and northern Idaho. Montana Bureau of Mines Geol. Spec. Pub., 94, 143–60.Google Scholar
Hietanen, A.H. (1967) Scapolite in the Belt Series in the St. Joe-Clearwater Region, Idaho. Geol. Soc. Amer. Spec. Pap., 86, 56pp.Google Scholar
Honnorez, J. and Kirst, P.(1975) Petrology of rodingites from the equatorial Mid-Atlantic fracture zones and their geotectonic significance. Contrib. Mineral. Petrol, 49, 233–57.CrossRefGoogle Scholar
Ito, E. and Anderson, A. T. Jr. (1983) Submarine metamorphism of gabbros from the Mid-Cayman Rise: Petrographic and mineralogic constraints on hydrothermal processes at slow-spreading ridges. Contrib. Mineral. Petrol, 82, 371–88.CrossRefGoogle Scholar
Jacobson, S. S. (1975) Dashkesanite: High-chlorine amphibole from St. Paul's Rocks, Equatorial Atlantic, and Transcausasia. U.S.S.R. Mineral Science Investigations, Contrib. Earth Sci., Smith-sonian Institute, 14, 17–20.Google Scholar
Jiang, S-Y., Palmer, M. R., Li, Y-H. and Xue, C-J.(1993) Chemical compositions of tourmaline in the Yindongzi-Tongmugou Pb—Zn deposits, Qinling, China: Implications for the hydrothermal ore-forming processes. Submitted to Mineral Deposita. Google Scholar
Krutov, G. A. (1936) Dashkesanite: A new chlorine amphibole of the hastingsite group. Mineral. Abstr., 6, 438.Google Scholar
Leake, B. E. (1978) Nomenclature of amphiboles. Canad. Mineral, 16, 501–20.Google Scholar
Leelanandam, C. (1970) A chlorine rich biotite from Kondapalli, Andhra Pradesh, India. Amer. Mineral, 55, 1338–58.Google Scholar
Moine, B., Sauvan, P. and Jarousse, J. (1981) Geochemistry of evaporite-bearing series: A tentative guide to the identification of metaeva-porites. Contrib. Mineral. Petrol, 76, 401–12.CrossRefGoogle Scholar
Mora, C. I. and Valley, J. W.(1989) Halogen-rich scapolite and biotite: Implications for meta-morphic fluid-rock interaction. Amer. Mineral, 74, 721–37.Google Scholar
Munoz, J. L. (1984) F-OH and Cl-OH exchange in micas with applications to hydrothermal ore deposits. Rev. Mineral, 13, 469–93.Google Scholar
Munoz, J. L. and Swenson, A. (1981) Chloride-hydroxyl exchange in biotite and estimation of relative HC1/HF activities in hydrothermal fluids. Econ. Geol, 76, 2212–21.CrossRefGoogle Scholar
Nijland, T. G., Jansen, J. B. H. and Maijer, C. (1993) Halogen geochemistry of fluid during amphibolite-granulite metamorphism as indicated by apatite and hydrous silicates in basic rocks from the Bamble Sector, south Norway. Lithos, 30, 167–89.CrossRefGoogle Scholar
Oen, I. S. and Lustenhouwer, W. J. (1992) Cl-rich biotite, Cl-K hornblende, and Cl-rich scapolite in meta-exhalites, Nora, Bergslagen, Sweden. Econ. Geol, 87, 1638–48.CrossRefGoogle Scholar
Palmer, M. R.(1991) Boron isotope systematics of hydrothermal fluids and tourmalines: A synthese. Isotope Geosci., 14, 111–21.CrossRefGoogle Scholar
Palmer, M. R., and Slack, J. F.(1989) Boron isotopic composition of tourmaline from massive sulfide deposits and tourmalinites. Contrib. Mineral. Petrol, 103, 434–51.CrossRefGoogle Scholar
Pritchard, H. M. and Cann, J. R.(1982) Petrology and mineralogy of dredged gabbro from Gettysburg Bank, eastern Atlantic. Contrib. Mineral. Petrol, 79, 46–55.CrossRefGoogle Scholar
Roedder, E. (1984) Low-to medium-grade meta-morphic environments. Rev. Mineral, 12, 413–72.Google Scholar
Sisson, V. B. (1987) Halogen geochemistry as an indicator of metamorphic fluid interaction with the Ponder pluton, Coast Plutonic Complex, Bristish Columbia, Canada. Contrib. Mineral. Petrol, 95, 123–31.CrossRefGoogle Scholar
Vanko, D. A. (1986) High-chlorine amphiboles from oceanic rocks; products of highly-saline hydro-thermal fluids? Amer. Mineral, 71, 51–59.Google Scholar
Vanko, D. A. and Bishop, F. C. (1982) Occurence and origin of marialitic scapolite in the Humboldt Lopolith N.W. Nevada. Contrib. Mineral. Petrol, 81, 277–89.CrossRefGoogle Scholar
Volfinger, M., Robert, J-L., Velzeuf, D. and Neiva, A. M. R. (1985) Structural control of the chlorine content of OH-bearing silicates (micas and amphiboles). Geochim. Cosmochim. Ada, 49, 37–48.CrossRefGoogle Scholar
Xue, C-J., Qi, S-J. and Liang, W-Y.(1989) A special scapolite—biotite rock in the mid-Devonian marine basin in eastern Qinling. J. Xi'an Coll. Geol, 1, 30–39.Google Scholar
Zhang, B-Y., Chen, D-X., Li, Z-J and Gu, X. M.(1989) The regional geochemistry of the Zhashui-Shanyang mineralization belt. Chinese Geol. Univ. Pub. House, Beijing, 249pp.Google Scholar