得尔布干成矿区(北片)成矿条件初步研究

    THE FORMING CONDITIONS OF NONFERROUS AND PRECIOUS METAL DEPOSITS IN THE NORTH OF DERBUGAN METALLOGENIC PROVINCE

    • 摘要: 该区有色、贵金属矿床的主成矿期为晚侏罗世-早白垩世.不同成因类型矿床成矿温度亦有差异,"斑岩型"属中高温矿床,"火山热液型"属中低温矿床,"新类型"金矿床和"浅成低温热液型"金矿应属低温热液矿床.有色、贵金属矿床中S的来源主要与深源岩浆关系密切,成因类型应属广义的"岩浆热液型矿床",但有少量S来源于容矿岩或为外生S.成矿热液的主体或组成的总趋势,是以岩浆水和大气降水的混合水为特征,热源来自中生代火山侵入岩浆,而莫尔道嘎金矿点是浅成低温热液型,其成矿热液的主体是大气降水.西吉诺山方铅矿包裹体除了显示出岩浆热液的性质外,更多地反映了地下热卤水的介质特征.

       

      Abstract: The north of Derbugan metallogenic provice is located in the north of Inner Mongolia Autonomous Region and the north of Heilongjiang Provice.The principal metallogenetic epoch is J 3-K 1.The metallogenic temperatures vary for different genetic types of deposits.Porphyry-type deposits are formed at high-medium temperature;volcanic hydrothermal type,at medium-low temperature;while "New-type" and epithermal type,at low temperature.The sulfur isotopic values of δ34S form 8 deposits show a high concentration on -6‰ to +6‰.The peak values are around +2‰ to +6‰,indicating that the sulfur in the endogenetic polymetals,gold and silver deposits comes mainly form anatectic magma.The oxygen isotopic values of δ18O from 6 deposits are -4.5‰ and +23.9‰,showing a close relationship to the magmatic oringin.According to the hydrogen isotope of inclusion, the δ18O H2O values range from -12.9‰ to +12.6‰,and the δD is mainly in -89‰ to -105‰.Therefore,the oxygen and hydrogen isotopes of ore-bearing hydrothermal solution reflect the characteristics of magmatic water mixed with miscible fluids from surface precipitation,but the epithermal deposits are characterized by meteoric water.The analysis shows that the metallogenic hydrothermal solution of the deposits is derived from magmatic solution and geothermal brine.

       

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