下扬子巢湖地区鼓地1井五峰组-高家边组下段页岩地球化学特征及其地质意义

下扬子巢湖地区鼓地1井揭示了上奥陶统五峰组（WF2-3带）和下志留统高家边组下段（LM2带和LM5-6带）页岩。基于该套地层的页岩岩心样品的元素地球化学测试分析，对其沉积构造背景、物源区背景、古气候、古生产力、海水深度和盐度、氧化还原条件进行了研究。结果表明，鼓地1井五峰组-高家边组下段页岩主量元素、微量元素以及稀土元素纵向分布不均匀，LM2带与WF2-3带和LM5-6带相比明显异常。沉积时期的构造环境主要为活动大陆边缘，同时兼具大陆岛弧的特征。物源具有长英质物源和成熟大陆石英物源混合物源的特征。WF2-3带和LM5-6带为浅水环境，底层海水含氧高，气候温暖湿润，古生产力较低，海水较浅且盐度较低；LM2带为深水环境，海水盐度高、滞留程度较弱，底层海水缺氧，气候干燥炎热，古生物生产力较强。

Geochemical characteristics and geological significance of shale in the lower member of Wufeng-Gaojiabian Formation of Well Gudi 1 in Chaohu area,Lower Yangtze region

Well Gudi 1 reveals the strata of the WF2-3 member of Wufeng Formation (Upper Ordovician) and the LM2 and LM5-6 members of lower member of Gaojiabian Formation (Lower Silurian). The element geochemistry characteristics of shale samples from the studied strata has been analyzed, and its sedimentary tectonic background, provenance background, paleoclimate, paleoproductivity, seawater depth and salinity, redox conditions are thus studied subsequently. The results show that the vertical distribution of major elements, trace elements and rare earth elements in the shale of the lower member of Wufeng Formation-Gaojiabian Formation of well Gudi 1 is uneven, and the LM2 member is obviously abnormal compared with WF2-3 member and LM5-6 member. The tectonic environment during the sedimentary period is mainly the active continental margin environment, which also has the characteristics of continental island arc. The provenance is characterized by a mixture of felsic provenance and mature continental quartz provenance. WF2-3 and LM5-6 are in shallow water environment, with high oxygen content in bottom seawater, warm and humid climate, low paleoproductivity, shallow seawater and low salinity; LM2 member is a deep-water environment with high seawater salinity and weak retention. The bottom seawater is anoxic, dry and hot climate and strong paleontological productivity.