A NEW SOURCE OF ORGANIC MATTER IN ORE-FORMING FLUID OF METALLIC DEPOSITS: ENCLOSED ORGANIC MATTER OF HYDROCARBON SOURCE ROCKS
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摘要: 金属矿床有机质的来源问题是探讨生物成矿作用的重点和难点之一.赋存于石炭系的南京栖霞山多金属矿床, 其成矿流体中的有机质与下扬子区上、下古生界烃源岩吸咐有机质以及海相原油均存在较大差异.特别是表现在有机质族组成、三环萜的w(C23)/w(C21)比值、三萜w(Ts)/w(Tm)比值、w(γ-蜡烷)/w(C31αβS-升藿烷)比值以及甾烷系列的不同上.相反, 流体中的有机质在诸多方面与寒武系碳酸盐岩(矿床的矿源层之一)的晶胞有机质类似, 两者存在渊源关系.Abstract: The source of the organic matter in the metallic deposit is one of the important and difficult issues for the research into the biological mineralization. Relatively great differences, especially in terms of organic group constituents, w(C23)/w(C21) ratios of tricyclicterpanes, w(Ts)/w(Tm) ratios of triterpene, w(γ-cerotene)/w(C31αβS-hopane) ratios, and steranes series, are present between the organic matter in the metallogenic fluid in the Qixiashan polymetallic deposit, Nanjing occurring in the Carboniferous dolomites, and that, present as marine petroleum, adsorbed in the Upper and Lower Paleozoic hydrocarbon source rocks in the lower Yangtze region. However, the organic matter in the fluid is similar in several aspects to the enclosed organic matter in the Cambrian carbonate rocks (i.e., one of the mineral source strata), since the two kinds of organic matters are related to each other in their origin.
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图 1 烃源岩吸附有机质、晶胞有机质和成矿流体有机质的关系(烃源岩资料据文献[5])
1.矿石包裹体有机质; 2.矿石吸附有机质; 3.烃源岩吸附有机质; 4.烃源岩晶胞有机质; 5.海相原油
Fig. 1. Organic matter in the fluid proved not to be directly from the adsorbed organic matter in hydrocarbon source rocks
图 2 不同赋存状态有机质在萜类分布上的异同点
图中显示了成矿流体有机质在萜类组成上与烃源岩晶胞有机质类似, 而与吸附有机质相差较大, 特别在涂黑处.数字代表碳数.a.成矿流体有机质; b.寒武系(⋲2p) 晶胞有机质; c.赋矿地层(C2) 吸附有机质; d.寒武系(⋲2p) 吸附有机质, 其中b, d资料源自文献[5]
Fig. 2. Terpane distribution of organic matter from different occurrence
表 1 成矿流体有机质与上、下古生界烃源岩吸附有机质的差异
Table 1. Organic matter difference among the fluid and hydrocarbon source rocks in Upper and Lower Paleozoic
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