| 陆建军,王鹤年,沈渭洲,戴爱华.河台金矿同位素地质研究[J].地质找矿论丛,1990,(1):84-92 |
| 河台金矿同位素地质研究 |
| STUDY ON ISOTOPE GEOLOGY OF HETAI GOLD DEPOSIT |
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| DOI：10.6053/j.issn.1001-1412.1990.1. 008 |
| 中文关键词: 河台金矿床 稳定同位素 物质来源 成矿热液 |
| 英文关键词: |
| 基金项目: |
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| 中文摘要: |
| 氢、氧同位素研究表明河台金矿床成矿溶液由变质-岩浆水和大气降水混合而成,且随着成矿作用进行,加入到热液中的大气降水就愈多。硫、铅同位素特征表明它们均来自于震旦系地层。稳定同位素结合矿床地质和地球化学研究表明成矿物质金等是通过变质作用、混合岩化作用和岩浆作用从震旦系含金矿源层中活化转移而来。 |
| 英文摘要: |
| The Hetai gold deposit occurs in mylonite zones produced by ductile deformation of the Sinian strata, and is associated in space with metamorphic rocks, migmatites, and granites. δ18O values of quartz from gold ores range from 7.0 to 14.5‰, with an average being 10.6‰; δDH2O values of fluid inclusions in quartz vary from -54.0 to -84.0‰, with an average being -67.9‰; Calculated δ18OH2O values of fluids in equilibrium with quartz and calcite vary significantly from -5.21 to 8.04‰. δ18OH2O values tend to decrease gradually with decreasing temperature. The values of δDH2O and δ18OH2O show marked scattering, and fall on the δDH2O-δ18OH2O diagram between meteoric -water line and the area of metamorphic and magmatic waters. The oxygen and hydrogen isotope characteristics indicate that ore-forming fluids were mixturs of meteoric, metamorphic and magmatie waters. The early hydrothermal fluids were more likely to be composed mainly of metamorphic and magamatic waters. Meteoric water might have played a more important role at lower temperature. δ34S values of pyrites range from -3.1 to -1.7‰(the average being -2.28‰), which are comparable to those from mylonites(the average of δ34S-1.9‰). The averages of 206Pb/204Pb in pyrite, galena, metamorphics and feldspar seperated from pegmatites and granites are 18.899, 18.828, 19.53, 18.613 and 18.532 respectively; The 207Pb/204Pb 15.734, 15.732, 15.88, 15.680, and 15.613 respectively; The 208Pb/204Pb 39.244, 39.178, 38.41, 38.726, and 38.656. All these lead isotopes are radiogenic and have high μ values, which indicate their derivation from the upper crust enriched in uranium. The calibrated lead isotopes of metamorphics(206Pb/204Pb being 19.10, 207Pb/204Pb, 15.877)are analogous to those of ore lead. Sulfur and lead isotope characteristics imply that ore-forming component may have been derived from the source strata of gold. The gold contents in the Sinian strata are very high(the average 13.6 pbb). Gold from the strata were mobilized, transported, and enriched in favourable places during regional metamorphism, migmatization, fault-metamorphism, and magmatism. |
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