投稿时间：2012-04-27
修订日期：2013-05-05
中文摘要:乌拉根铅锌矿床位于塔里木盆地西北缘的喀什凹陷中,含矿岩石为一套中-新生代砂砾岩,矿区伴随铅锌矿化普遍产出大量油气残留物、干沥青等有机质。文章通过有机碳、硫、氯仿沥青"A"及其族组成和饱和烃气相色谱分析等有机地球化学方法,对乌拉根铅锌矿的有机质进行测试分析,进而探讨了有机质在铅锌矿床形成过程中的作用。测试结果显示,乌拉根矿区铅锌的有机碳、硫含量均较高,表明其铅锌的成矿作用与油气的还原作用关系密切,铅锌等成矿元素是在还原状态下沉淀富集的。矿区有机质的氯仿沥青"A"变化不大(0.004%~0.025%)。A的族组分中,总烃平均为46.22%,"非烃+沥青质"平均为53.77%,饱和烃/芳香烃平均为9.59,具I型有机母质特征。饱和烃气相色谱参数特征分析显示,有机质以海相为主,母质来源以藻类为主。矿区样品中,Pr/Ph为0.41~1.84,平均为1.04,说明有机质是处在还原环境中的;OEP为0.75~1.07,平均为0.92,显示了有机质高成熟的特征;CPI为1.03~1.30,平均为1.16,指示热演化程度较高。综合野外证据和测试结果,表明油气活动参与了乌拉根铅锌矿床的成矿作用,油气还原是成矿金属元素富集沉淀成矿的重要因素。
Abstract:The Wulagen lead-zinc deposit, located in Kashi Sag on the northwestern margin of the Tarim basin of Xinjiang, is hosted in Mesozoic-Cenozoic sandstones and conglomerates, where lots of organic matters are widely spread, such as residues of oil and gas and dry asphalt. This paper mainly presents analytical data of organic carbon, sulfur, chloroform bitumen "A" and its group composition, and saturated hydrocarbons detected by gas chromatography in ore bodies and host rocks, so as to better understand the roles of organic mater in the minera-lization of lead and zinc. The results show that the composition of organic and sulfur in lead-zinc ores is relatively rich, suggesting that the lead-zinc mineralization was closely related to the reduction of oil and gas. The content of chloroform bitumen "A" in organic matter varies from 0.004% to 0.025%. The ratio of total hydrocarbons is 46.22% on average, that of "non-hydrocarbon+asphaltenes" is 53.77% on average, and the average ratio of saturated hydrocarbons to aromatic hydrocarbons is 9.59, implying that the organic matter is similar to I-type parent material. These characteristics suggest that the organic matter might have been sourced from the marine algae. The ratios of Pr/Ph in ores and rocks vary from 0.41 to 1.84, with 1.04 on average, indicating a deoxidization environment for the organic matter. Odd-even predominance indices (OEP) vary from 0.75 to 1.07, averagely 0.92, showing that the maturity of organic matter is relatively high. Carbon preference indices (CPI) are from 1.03 to 1.30, with 1.16 on average, indicating a higher degree in thermal evolution. Field evidence and analytical results of organic matter in ores and rocks suggest that the oil and gas took part in the lead-zinc mineralization, and the deoxidization of oil and gas played an important role in the deposition and enrichment of ore-forming elements such as lead and zinc.
文章编号：
中图分类号：P618.42;P618.43
文献标志码：
基金项目:本文得到国家自然科学基金项目(41072071);国家重点基础研究发展计划(973)项目(2007CB411305);国家305项目(2011BAB06B05-03)中国地质科学院地质力学研究所基本科研业务费项目(DZLXJK201209)和公益性行业科研专项(深部探测项目)(2011311191-02)的联合资助
引用文本：
韩凤彬,陈正乐,刘增仁,陈柏林,崔玲玲,丁文君,蒋荣宝,李丽.2013.西南天山乌拉根铅锌矿床有机地球化学特征及其地质意义[J].矿床地质,32(3):591~602HAN FengBin,CHEN ZhengLe,LIU ZengRen,CHEN BaiLin,CUI LingLing,DING WenJun,JIANG RongBao,LI Li.2013.Organic geochemistry of Wulagen Pb-Zn deposit in Southwest Tianshan Mountains and its implications[J].Mineral Deposits32(3):591~602
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