【摘要】：下?lián)P子寧鎮(zhèn)地區(qū)上奧陶統(tǒng)五峰組—下志留統(tǒng)高家邊組沉積了一套良好的黑色烴源巖。本文以江蘇句容侖山5號(hào)井巖心為研究對(duì)象,進(jìn)行系統(tǒng)的巖相學(xué)研究與地球化學(xué)分析。該套巖系以黑色頁(yè)巖夾硅質(zhì)巖為主,夾多層火山灰薄層,筆石化石豐富。其中,五峰組底部發(fā)育鈣質(zhì)、硅鈣質(zhì)頁(yè)巖,頂部以黑色頁(yè)巖為主,SiO_2含量最高值82.38%,黑色頁(yè)巖中存在硅質(zhì)巖夾層,硅質(zhì)巖夾層的形成可能與上升流及火山噴發(fā)帶來(lái)的熱液有關(guān)。高家邊組底部與五峰組界限附近主要為黑色頁(yè)巖。底部非黑色頁(yè)巖段以粉砂-砂質(zhì)泥巖與灰白-灰黑色頁(yè)巖為主。δ~(13)C_(org)在奧陶系—志留系界限附近呈明顯負(fù)偏移,反映海平面的迅速回升。五峰組與高家邊組界限處微量元素氧化還原指標(biāo)U/Th,V/(V+Ni),V/Cr,Ni/Co,V/Sc指示貧氧-缺氧環(huán)境,為有機(jī)質(zhì)的保存提供了有利條件。草莓狀黃鐵礦的發(fā)現(xiàn)也為缺氧環(huán)境提供了證據(jù)。研究區(qū)巖石稀土元素配分型式較平坦,在五峰組和高家邊組界限處局部出現(xiàn)Ce負(fù)異常,指示還原環(huán)境,且在界限附近Eu正異常最為顯著,反映熱液作用的影響。上奧陶統(tǒng)五峰組黑色頁(yè)巖段和下志留統(tǒng)高家邊組黑色頁(yè)巖段為深水陸棚沉積,是良好的烴源巖發(fā)育區(qū),向上至高家邊組非黑色頁(yè)巖段變?yōu)闇\水陸棚沉積。五峰組—高家邊組黑色烴源巖的形成受到了上升流、熱液以及海平面回升等因素的多重影響。
[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.
【作者單位】： 北京大學(xué)地球與空間科學(xué)學(xué)院;南京大學(xué)地球科學(xué)與工程學(xué)院;
【基金】：江蘇省科技支撐計(jì)劃(工業(yè))(BE2013115)
【分類號(hào)】：P534.42;P618.13
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本文編號(hào)：2196424