中国东部陆相渤海湾盆地东营凹陷古近系沙河街组油页岩中有机质的富集机制一直是研究热点,但关于异养生物及硫循环对有机质富集过程影响的研究较少.通过有机地球化方法对东营凹陷沙河街组第三、四段富有机质烃源岩进行精细研究,认为伴...中国东部陆相渤海湾盆地东营凹陷古近系沙河街组油页岩中有机质的富集机制一直是研究热点,但关于异养生物及硫循环对有机质富集过程影响的研究较少.通过有机地球化方法对东营凹陷沙河街组第三、四段富有机质烃源岩进行精细研究,认为伴随着明显的水体分层,藻类勃发进一步加剧了底水缺氧的条件,海水带来了丰富的硫酸盐促进了强烈的细菌硫还原(Bacterial Sulfur Reduction,BSR)作用,将这种缺氧条件进一步扩展到水柱上部形成透光层缺氧(Photic Zone Euxinia,PZE),而PZE有利于光合自养绿硫菌的剧烈活动.强烈的BSR作用及间歇性的PZE控制东营凹陷古湖盆中藻类等水生生物的组成,原核细菌及海相金藻类对有机质富集有一定贡献.通过分析海相藻类生物标志物C3024-正丙基胆甾烷和透光层缺氧生物标志物异海绵烷与有机碳丰度的关系,研究认为在相对丰富的外源硫酸盐输入、厌氧异养细菌作用、光能自养细菌作用和透光层缺氧条件下形成的硫循环,对东营古湖盆沙河街组烃源岩有机质的富集起主要控制作用.展开更多
Continental epithermal ore deposits are commonly associated with sedimentary organic matter,oils or solid bitumen.These organics embedded in mineral deposits can convey valuable information of the ore genesis.However,...Continental epithermal ore deposits are commonly associated with sedimentary organic matter,oils or solid bitumen.These organics embedded in mineral deposits can convey valuable information of the ore genesis.However,the extent to which the formation of ore minerals was recorded by organic compounds remains largely unknown,as also is how metal-rich ores interfere with the molecular proxies in the temperature regime envisaged for hydrothermal activity.The molecular compositional changes of various polycyclic aromatic steranes and polycyclic aromatic hydrocarbons and compounds derived from the Jinding Pb/Zn deposit,SW China provide new data.Aliphatic regular steranes are present as traces.The transformation from polycyclic aromatic steranes to unsubstituted polycyclic aromatic hydrocarbons is observed to show an increased trend with increasing hydrothermal alteration levels;this is consistent with the transformation from unsubstituted polycyclic aromatic hydrocarbons to heterocyclic compounds.Dehydrocyclization(aromatization)of polycyclic biological compounds and hydrodecyclization(dearomatization)of polycyclic aromatic compounds are two important reaction pathways in hydrothermal systems with moderate temperature.This detailed investigation of organicinorganic interactions of two groups of polycyclic compounds with metal-rich ores provides insights into the questions on how and to what extent the formation of Pb/Zn deposits can be recorded by organics.This work will improve our understanding of carbon reduction,oxidation or condensation in the deep Earth and the carbon exchange between the Earth's crust and mantle,and may shed light on the processes for ultra-deep hydrocarbon exploration.展开更多
文摘中国东部陆相渤海湾盆地东营凹陷古近系沙河街组油页岩中有机质的富集机制一直是研究热点,但关于异养生物及硫循环对有机质富集过程影响的研究较少.通过有机地球化方法对东营凹陷沙河街组第三、四段富有机质烃源岩进行精细研究,认为伴随着明显的水体分层,藻类勃发进一步加剧了底水缺氧的条件,海水带来了丰富的硫酸盐促进了强烈的细菌硫还原(Bacterial Sulfur Reduction,BSR)作用,将这种缺氧条件进一步扩展到水柱上部形成透光层缺氧(Photic Zone Euxinia,PZE),而PZE有利于光合自养绿硫菌的剧烈活动.强烈的BSR作用及间歇性的PZE控制东营凹陷古湖盆中藻类等水生生物的组成,原核细菌及海相金藻类对有机质富集有一定贡献.通过分析海相藻类生物标志物C3024-正丙基胆甾烷和透光层缺氧生物标志物异海绵烷与有机碳丰度的关系,研究认为在相对丰富的外源硫酸盐输入、厌氧异养细菌作用、光能自养细菌作用和透光层缺氧条件下形成的硫循环,对东营古湖盆沙河街组烃源岩有机质的富集起主要控制作用.
基金financially supported by the National Key Research and Development Program of China(Grant No.2019YFA0708504)National Natural Science Foundation of China(Grant Nos.U20B6001,42141021,42102185)。
文摘Continental epithermal ore deposits are commonly associated with sedimentary organic matter,oils or solid bitumen.These organics embedded in mineral deposits can convey valuable information of the ore genesis.However,the extent to which the formation of ore minerals was recorded by organic compounds remains largely unknown,as also is how metal-rich ores interfere with the molecular proxies in the temperature regime envisaged for hydrothermal activity.The molecular compositional changes of various polycyclic aromatic steranes and polycyclic aromatic hydrocarbons and compounds derived from the Jinding Pb/Zn deposit,SW China provide new data.Aliphatic regular steranes are present as traces.The transformation from polycyclic aromatic steranes to unsubstituted polycyclic aromatic hydrocarbons is observed to show an increased trend with increasing hydrothermal alteration levels;this is consistent with the transformation from unsubstituted polycyclic aromatic hydrocarbons to heterocyclic compounds.Dehydrocyclization(aromatization)of polycyclic biological compounds and hydrodecyclization(dearomatization)of polycyclic aromatic compounds are two important reaction pathways in hydrothermal systems with moderate temperature.This detailed investigation of organicinorganic interactions of two groups of polycyclic compounds with metal-rich ores provides insights into the questions on how and to what extent the formation of Pb/Zn deposits can be recorded by organics.This work will improve our understanding of carbon reduction,oxidation or condensation in the deep Earth and the carbon exchange between the Earth's crust and mantle,and may shed light on the processes for ultra-deep hydrocarbon exploration.
