宁镇地区上奥陶统五峰组—下志留统高家边组底部黑色岩系地球化学特征与沉积环境分析
发布时间：2018-08-22 07:35
【摘要】：下扬子宁镇地区上奥陶统五峰组—下志留统高家边组沉积了一套良好的黑色烃源岩。本文以江苏句容仑山5号井岩心为研究对象,进行系统的岩相学研究与地球化学分析。该套岩系以黑色页岩夹硅质岩为主,夹多层火山灰薄层,笔石化石丰富。其中,五峰组底部发育钙质、硅钙质页岩,顶部以黑色页岩为主,SiO_2含量最高值82.38%,黑色页岩中存在硅质岩夹层,硅质岩夹层的形成可能与上升流及火山喷发带来的热液有关。高家边组底部与五峰组界限附近主要为黑色页岩。底部非黑色页岩段以粉砂-砂质泥岩与灰白-灰黑色页岩为主。δ~(13)C_(org)在奥陶系—志留系界限附近呈明显负偏移,反映海平面的迅速回升。五峰组与高家边组界限处微量元素氧化还原指标U/Th,V/(V+Ni),V/Cr,Ni/Co,V/Sc指示贫氧-缺氧环境,为有机质的保存提供了有利条件。草莓状黄铁矿的发现也为缺氧环境提供了证据。研究区岩石稀土元素配分型式较平坦,在五峰组和高家边组界限处局部出现Ce负异常,指示还原环境,且在界限附近Eu正异常最为显著,反映热液作用的影响。上奥陶统五峰组黑色页岩段和下志留统高家边组黑色页岩段为深水陆棚沉积,是良好的烃源岩发育区,向上至高家边组非黑色页岩段变为浅水陆棚沉积。五峰组—高家边组黑色烃源岩的形成受到了上升流、热液以及海平面回升等因素的多重影响。
[Abstract]:The upper Ordovician Wufeng formation and Lower Silurian Gaojiabian formation in the Lower Yangtze and Ningzhen area have deposited a good set of black source rocks. In this paper, a systematic petrographic study and geochemical analysis are carried out on the core of well No. 5 of Jurong Lun Mountain, Jiangsu Province. The series is mainly composed of black shale intercalated siliceous rocks with multi-layer volcanic ash thin layer and abundant graptolite fossils. In the Wufeng formation, calcareous and siliceous shale are developed at the bottom of Wufeng formation, and the highest content of SiO2 in black shale is 82.38. The formation of siliceous intercalation may be related to upwelling and volcanic eruption. Black shale is mainly near the bottom of Gaojiabian formation and Wufeng formation. The non-black shale formation at the bottom is dominated by silt sandy mudstone and gray white gray black shale. 未 ~ (13) C _ (org) shows a negative migration near the Ordovician-Silurian boundary, which reflects the rapid rise of sea level. At the boundary of Wufeng formation and Gao Jiabian formation, the trace element redox index (U / T V / (V Ni) V / Cr / Ni / CoV / SC) indicates the oxygen-anoxic environment and provides favorable conditions for the preservation of organic matter. The discovery of strawberry pyrite also provides evidence for hypoxia. The REE partitioning pattern of rocks in the study area is relatively flat, and there are negative ce anomalies at the boundary of Wufeng formation and Gajiabian formation, indicating the reduction environment, and the positive EU anomaly near the boundary is the most obvious, which reflects the effect of hydrothermal action. The black shale formation of Wufeng formation of Upper Ordovician and the black shale formation of Gaojiabian formation of Lower Silurian are deep-water shelf deposits, which are good source rock development areas. The formation of black source rocks in Wufeng and Gajiabian formation is influenced by the upwelling, hydrothermal and sea level rise.
【作者单位】： 北京大学地球与空间科学学院;南京大学地球科学与工程学院;
【基金】：江苏省科技支撑计划(工业)(BE2013115)
【分类号】：P534.42;P618.13
，
本文编号：2196424
[Abstract]:The upper Ordovician Wufeng formation and Lower Silurian Gaojiabian formation in the Lower Yangtze and Ningzhen area have deposited a good set of black source rocks. In this paper, a systematic petrographic study and geochemical analysis are carried out on the core of well No. 5 of Jurong Lun Mountain, Jiangsu Province. The series is mainly composed of black shale intercalated siliceous rocks with multi-layer volcanic ash thin layer and abundant graptolite fossils. In the Wufeng formation, calcareous and siliceous shale are developed at the bottom of Wufeng formation, and the highest content of SiO2 in black shale is 82.38. The formation of siliceous intercalation may be related to upwelling and volcanic eruption. Black shale is mainly near the bottom of Gaojiabian formation and Wufeng formation. The non-black shale formation at the bottom is dominated by silt sandy mudstone and gray white gray black shale. 未 ~ (13) C _ (org) shows a negative migration near the Ordovician-Silurian boundary, which reflects the rapid rise of sea level. At the boundary of Wufeng formation and Gao Jiabian formation, the trace element redox index (U / T V / (V Ni) V / Cr / Ni / CoV / SC) indicates the oxygen-anoxic environment and provides favorable conditions for the preservation of organic matter. The discovery of strawberry pyrite also provides evidence for hypoxia. The REE partitioning pattern of rocks in the study area is relatively flat, and there are negative ce anomalies at the boundary of Wufeng formation and Gajiabian formation, indicating the reduction environment, and the positive EU anomaly near the boundary is the most obvious, which reflects the effect of hydrothermal action. The black shale formation of Wufeng formation of Upper Ordovician and the black shale formation of Gaojiabian formation of Lower Silurian are deep-water shelf deposits, which are good source rock development areas. The formation of black source rocks in Wufeng and Gajiabian formation is influenced by the upwelling, hydrothermal and sea level rise.
【作者单位】： 北京大学地球与空间科学学院;南京大学地球科学与工程学院;
【基金】：江苏省科技支撑计划(工业)(BE2013115)
【分类号】：P534.42;P618.13
，
本文编号：2196424
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