Factors Controlling Deposition of Metallic Minerals in the Meng’entaolegai Ag-Pb-Zn Deposit, Inner Mongolia, China: Evidence from Fluid Inclusions, Isotope Systematics, and Thermodynamic Model

Abstract

The Meng’entaolegai Ag-Pb-Zn vein-type deposit in Inner Mongolia, NE China is hosted in biotite/muscovite granite. This deposit includes the western (Zn-rich, deepest), middle (Zn-Pb rich) and eastern (Pb-Ag-rich, shallowest) ore-blocks. To better understand the metallogenic processes in ore district, we have undertaken a series of studies including fluid inclusion microthermometry, H-O-S-Pb isotope compositions and thermodynamic modeling. Based on fluid inclusion petrography, microthermometry results and HO isotope compositions, the ore-forming H₂O-NaCl fluid inclusions are characterized by medium temperature and medium salinity. And two kinds of fluid processes (boiling in western and middle ore-block and fluid mixing in the eastern ore-block) were identified to explain the ore fluid evolution. More importantly, log ƒ_O2- pH diagrams of δ₃₄S contours with the stability fields of Fe- and Cu-, Zn-, Pb-, and Ag-bearing minerals were constructed to restore the physicochemical conditions of ore-forming fluid in the western (270 °C and 80 bars), middle (250 °C and 70 bars), and eastern (230 °C and 50 bars) ore-blocks. As a result, the ore-forming conditions in the western and middle ore-block were similar. In the eastern ore-block, the fluids may have changed from acidic, S-poor and δ₃₄S(ΣS)≈2.8 to neutral, S-richer and δ₃₄S(ΣS)≈0.5, which imply that neutral S-rich meteoric water was mixed with the magmatic fluid. Meanwhile, the activity of Ag+ was estimated to be about 10 ppm–9 ppm in the middle ore-block, but in the eastern ore-block it was about ~10 ppm–12 ppm. We proposed that the key for Ag ore deposition was likely to be neutralization led by fluid mixing.

Keywords

fluid inclusions / isotope systematics / thermodynamic model / Ag-Pb-Zn deposit / Meng’entalegai / NE China

References

Chen Y J, Chen H Y, Zaw K, . Geodynamic Settings and Tectonic Model of Skarn Gold Deposits in China: An Overview. Ore Geology Reviews, 2011, 31(1/2/3/4): 139-169.

Chi G X, Haid T, Quirt D, . Petrography, Fluid Inclusion Analysis, and Geochronology of the End Uranium Deposit, Kiggavik, Nunavut, Canada. Mineralium Deposita, 2011, 52(2): 211-232.

Chi G X, Lu H Z. Validation and Representation of Fluid Inclusion Microthermometric Data Using the Fluid Inclusion Assemblage (FIA) Concept. Acta Petrologica Sinica, 2011, 24(9): 1945-1953.

Clayton R N, Mayeda T K. The Use of Bromine Pentafluoride in the Extraction of Oxygen from Oxides and Silicates for Isotopic Analysis. Geochimica et Cosmochimica Acta, 2011, 27(1): 43-52.

Driesner T, Heinrich C A. The System H2O-NaCl. Part I: Correlation Formulae for Phase Relations in Temperature-Pressure-Composition Space from 0 to 1 000 °C, 0 to 5 000 bar, and 0 to 1 XNaCl. Geochimica et Cosmochimica Acta, 2011, 71(20): 4880-4901.

Fan H R, Hu F F, Wilde S A, . The Qiyugou Gold-Bearing Breccia Pipes, Xiong’ershan Region, Central China: Fluid-Inclusion and Stable-Isotope Evidence for an Origin from Magmatic Fluids. International Geology Review, 2011, 53(1): 25-45.

Giggenbach W F. Geochemistry of Hydrothermal Ore Deposits, 2nd Edition. Geochimica et Cosmochimica Acta, 2011, 46 5 833

Goldstein R H. Fluid Inclusions in Sedimentary and Diagenetic Systems. Lithos, 2011, 551/2/3/4: 159-193.

Greg M A, David A C. Thermodynamics in Geochemistry: The Equilibrium Model, 2011, Oxford: Oxford University Press, 1189.

Hedenquist J W, Henley R W. The Importance of CO2 on Freezing Point Measurements of Fluid Inclusions; Evidence from Active Geothermal Systems and Implications for Epithermal Ore Deposition. Economic Geology, 2011, 80(5): 1379-1406.

Helgeson H C, Kirkham D H. Theoretical Prediction of the Thermodynamic Behavior of Aqueous Electrolytes at High Pressures and Temperatures; II, Debye-Huckel Parameters for Activity Coefficients and Relative Partial Molal Properties. American Journal of Science, 2011, 274(10): 1199-1261.

Hennet R J C, Crerar D A, Schwartz J. Organic Complexes in Hydrothermal Systems. Economy Geology, 2011, 83(4): 742-764|url|.

Hollister L S, Burruss R C. Phase Equilibria in Fluid Inclusions from the Khtada Lake Metamorphic Complex. Geochimica et Cosmochimica Acta, 2011, 40(2): 163-175.

Jahn B M, . Malpas J, Fletcher C J N, Ali J R, . The Central Asian Orogenic Belt and Growth of the Continental Crust in the Phanerozoic. Aspects of the Tectonic Evolution of China. Special Publication 226, 2011, 73-100.

Jiang S H, Nie F J, Liu Y F, . Geochronology of Intrusive Rocks Occurring in and around the Mengentaolegai Silver-Polymetallic Deposit, Inner Mongolia. Journal of Jilin University (Earth Science Edition), 2011, 46(6): 1755-1769|url|.

Johnson J W, Oelkers E H, Helgeson H C. SUPCRT92: A Software Package for Calculating the Standard Molal Thermodynamic Properties of Minerals, Gases, Aqueous Species, and Reactions from 1 to 5 000 Bar and 0 to 1 000 °C. Computers & Geosciences, 2011, 18(7): 899-947.

Kissin S A, Mango H. Silver Vein Deposits, 2011, Oxford: Treatise on Geochemistry, Elsevier, 425-432.

Klemm L M, Pettke T, Heinrich C A, . Hydrothermal Evolution of the El Teniente Deposit, Chile: Porphyry Cu-Mo Ore Deposition from Low-Salinity Magmatic Fluids. Economic Geology, 2011, 102(6): 1021-1045.

Li X M, Li Z K, Xiong S K, . Mineralization Characteristics of the Laoliwan Ag-Pb-Zn Deposit and Geochemical Features of the Ore-Bearing Granite Porphyry in the Southern North China Craton: Implications for Ore Genesis. Earth Science, 2011, 44(1): 69-87.

Liu C H, Bagas L, Wang F X. Isotopic Analysis of the Super- Large Shuangjianzishan Pb-Zn-Ag Deposit in Inner Mongolia, China: Constraints on Magmatism, Metallogenesis, and Tectonic Setting. Ore Geology Reviews, 2011, 75: 252-267.

Liu Y F, Jiang S H, Bagas L. The Genesis of Metal Zonation in the Weilasituo and Bairendaba Ag-Zn-Pb-Cu-(Sn-W) Deposits in the Shallow Part of a Porphyry Sn-W-Rb System, Inner Mongolia, China. Ore Geology Reviews, 2011, 75: 150-173.

Maanijou M, Rasa I, Lentz D R. Petrology, Geochemistry, and Stable Isotope Studies of the Chehelkureh Cu-Zn-Pb Deposit, Zahedan, Iran. Economic Geology, 2011, 107(4): 683-712.

Mao J W, Xie G Q, Zhang Z H, . Mesozoic Large-Scale Metallogenic Pluses in North China and Corresponding Geodynamic Settings. Acta Petrolei Sinica, 2011, 21: 169-188. (in Chinese with English Abstract)

Ohmoto H. Systematics of Sulfur and Carbon Isotopes in Hydrothermal Ore Deposits. Economic Geology, 2011, 67(5): 551-578.

Ohmoto H, Goldhaber M B. Barnes H L. Sulfur and Carbon Isotopes. Geochemistry of Hydrothermal Ore Deposits, 2011, New York: Wiley, 517-611.

Ouyang H G, Mao J W, Santosh M, . The Early Cretaceous Weilasituo Zn-Cu-Ag Vein Deposit in the Southern Great Xing’an Range, Northeast China: Fluid Inclusions, H, O, S, Pb Isotope Geochemistry and Genetic Implications. Ore Geology Reviews, 2011, 56: 503-515.

Qi J P, Chen Y J, Pirajno F. Geological Characteristics and Tectonic Setting of the Epithermal Deposits in the Northeast China. Journal of Mineralogy & Petrology, 2011, 25: 47-59.

Robinson B W, Kusakabe M. Quantitative Preparation of Sulfur Dioxide, for Sulfur-34/Sulfur-32 Analyses, from Sulfides by Combustion with Cuprous Oxide. Analytical Chemistry, 2011, 47(7): 1179-1181.

Robinson B W, Ohmoto H. Mineralogy, Fluid Inclusions, and Stable Isotopes of the Echo Bay U-Ni-Ag-Cu Deposits, Northwest Territories, Canada. Economic Geology, 2011, 68(5): 635-656.

Roedder E. Ribbe P H. Fluid Inclusions. Reviews in Mineralogy, 1984, Chantilly: Mineralogical Society of America, 644.

Ruan B X, Lü X B, Yang W, . Geology, Geochemistry and Fluid Inclusions of the Bianjiadayuan Pb-Zn-Ag Deposit, Inner Mongolia, NE China: Implications for Tectonic Setting and Metallogeny. Ore Geology Reviews, 2011, 71: 121-137.

Shu Q H, Chang Z S, Lai Y, . Regional Metallogeny of Mo- Bearing Deposits in Northeastern China, with New Re-Os Dates of Porphyry Mo Deposits in the Northern Xilamulun District. Economic Geology, 2011, 111(7): 1783-1798.

Shu Q, Lai Y, Sun Y, . Ore Genesis and Hydrothermal Evolution of the Baiyinnuo’er Zinc-Lead Skarn Deposit, Northeast China: Evidence from Isotopes (S, Pb) and Fluid Inclusions. Economic Geology, 2011, 108(4): 835-860.

Skirrow R G, Walshe J L. Reduced and Oxidized Au-Cu-Bi Iron Oxide Deposits of the Tennant Creek Inlier, Australia: An Integrated Geologic and Chemical Model. Economic Geology, 2011, 97(6): 1167-1202.

Steele-MacInnis M, Lecumberri-Sanchez P, Bodnar R J. HOKIEFLINCS_H2O-NACL: A Microsoft Excel Spreadsheet for Interpreting Microthermometric Data from Fluid Inclusions Based on the PVTX Properties of H2O-NaCl. Computers & Geosciences, 2011, 49: 334-337.

Su W C, Hu R Z, Qi L, . Trace Elements in Fluid Inclusions in the Carlin-Type Gold Deposits, Southwestern Guizhou Province. Chinese Journal of Geochemistry, 2011, 20(3): 233-239.

Taylor H P Jr. The Application of Oxygen and Hydrogen Isotope Studies to Problem of Hydrothermal Alteration and Ore Deposition. Economic Geology, 2011, 69(6): 843-883.

Wang Z G, Wang K Y, Wan D, . Metallogenic Age and Hydrothermal Evolution of the Jidetun Mo Deposit in Central Jilin Province, Northeast China: Evidence from Fluid Inclusions, Isotope Systematics, and Geochronology. Ore Geology Reviews, 2011, 89: 731-751.

Wilde S A, Zhou J B. The Late Paleozoic to Mesozoic Evolution of the Eastern Margin of the Central Asian Orogenic Belt in China. Journal of Asian Earth Sciences, 2011, 113: 909-921.

Wilkinson J J. Fluid Inclusions in Hydrothermal Ore Deposits. Lithos, 2011, 55(1/2/3/4): 229-272.

Wu H Y, Zhang L C, Wan B, . Re-Os and 40Ar/39Ar Ages of the Jiguanshan Porphyry Mo Deposit, Xilamulun Metallogenic Belt, NE China, and Constraints on Mineralization Events. Mineralium Deposita, 2011, 46(2): 171-185.

Wu H Y, Zhang L C, Wan B, . Geochronological and Geochemical Constraints on Aolunhua Porphyry Mo-Cu Deposit, Northeast China, and Its Tectonic Significance. Ore Geology Reviews, 2011, 43(1): 78-91.

Zartman R E, Doe B R. Plumbotectonics-The Model. Tectonophysics, 2011, 75(1/2): 135-162.

Zeng Q D, Liu J M, Zhang Z L, . Geology and Lead-Isotope Study of the Baiyinnuoer Zn-Pb-Ag Deposit, South Segment of the Da Hinggan Mountains, Northeastern China. Resource Geology, 2011, 59(2): 170-180.

Zeng Q D, Liu J M, Zhang Z L, . Geology and Geochronology of the Xilamulun Molybdenum Metallogenic Belt in Eastern Inner Mongolia, China. International Journal of Earth Sciences, 2011, 100(8): 1791-1809.

Zhai D G, Liu J J. Gold-Telluride-Sulfide Association in the Sandaowanzi Epithermal Au-Ag-Te Deposit, NE China: Implications for Phase Equilibrium and Physicochemical Conditions. Mineralogy and Petrology, 2011, 108(6): 853-871.

Zhai D G, Liu J J, Cook N J, . Mineralogical, Textural, Sulfur and Lead Isotope Constraints on the Origin of Ag-Pb-Zn Mineralization at Bianjiadayuan, Inner Mongolia, NE China. Mineralium Deposita, 2011, 54(1): 47-66.

Zhai D G, Liu J J, Wang J P, . Fluid Evolution of the Jiawula Ag-Pb-Zn Deposit, Inner Mongolia: Mineralogical, Fluid Inclusion, and Stable Isotopic Evidence. International Geology Review, 2011, 55(2): 204-224.

Zhai D G, Liu J J, Wang J P, . Zircon U-Pb and Molybdenite Re-Os Geochronology, and Whole-Rock Geochemistry of the Hashitu Molybdenum Deposit and Host Granitoids, Inner Mongolia, NE China. Journal of Asian Earth Sciences, 2014, 79: 144-160.

Zhai D G, Liu J J, Zhang H Y, . Origin of Oscillatory Zoned Garnets from the Xieertala F-Zn Skarn Deposit, Northern China: In-situ LA-ICP-MS Evidence. Lithos, 2014, 190-191: 279-291.

Zhai D G, Liu J J, Zhang H Y, . S-Pb Isotopic Geochemistry, U-Pb and Re-Os Geochronology of the Huanggangliang Fe-Sn Deposit, Inner Mongolia, NE China. Ore Geology Reviews, 2014, 59: 109-122.

Zhang Q, Zhan X Z, Liu Z H, . Trace Element Geochemistry of Meng’entaolegai Ag-Pb-Zn-In Deposit, Inner Mongolia, China. Acta Mineralogica Sinica, 2011, 24(1): 39-47.

Zhang Q, Zhu X Q, He Y L, . Indium Enrichment in the Meng’entaolegai Ag-Pb-Zn Deposit, Inner Mongolia, China. Resource Geology, 2011, 56(3): 337-346.

Zhao Y M, Zhang D Q. Metallogeny and Prospective Evaluation of Copper-Polymetallic Deposits in the Da Hinggan Mountains and Its Adjacent Regions, 2011, Beijing: Seismological Press, 83-106 (in Chinese with English Abstract)

Zhu J J, Hu R, Richards J P, . Genesis and Magmatic- Hydrothermal Evolution of the Yangla Skarn Cu Deposit, Southwest China. Economic Geology, 2011, 110(3): 631-652.

Zhu X Q, Zhang Q, He Y L, . Hydrothermal Source Rocks of the Meng’entaolegai Ag-Pb-Zn Deposit in the Granite Batholith, Inner Mongolia, China: Constrained by Isotopic Geochemistry. Geochemical Journal, 2011, 40(3): 265-275.