萍乐坳陷地区吴家坪期沉积环境的元素地球化学指示  

Elemental Geochemical Indication of Sedimentary Environment in Wujiaping Period of Pingle Depression Area

作　　者：肖富强 章双龙 祁星 XIAO Fu-qiang;ZHANG Shuang-long;QI Xing(Jiangxi Coalfield Geological Survey and Research Institute, Nanchang 330001,China)

机构地区：[1]江西省煤田地质勘察研究院,江西南昌330001

出　　处：《东华理工大学学报（自然科学版）》2020年第3期231-239,共9页Journal of East China University of Technology(Natural Science)

基　　金：江西省页岩气专项基金项目(赣页调201502,赣页调201501);江西省煤田地质局2019科技项目(20190107)。

摘　　要：为了解萍乐坳陷地区吴家坪期沉积环境,采用元素地球化学法,对研究区YXZ02井、ZK2601井地层中各种元素含量及变化规律进行研究。结果显示,乐平组官山段Sr/Ba的比值小于老山段,说明官山段到老山段经历了水体由淡转咸过程,推断这一时期发生了一次海侵作用。乐平组官山段、老山段及七宝山组地层中的Ba、Ti、Fe、Zn含量逐渐降低,说明吴家坪期是一个物源供应减少、沉积速率变慢的过程。乐平组官山段下部泥岩段、粉砂岩段V/Cr的比值高于上部砂岩段,老山段中泥岩段的V/Cr比值高于灰岩段,均表明前者沉积环境还原性强于后者。吴家坪早期至晚期Zr含量减少,反映该时期沉积水体逐渐加深。该研究成果可为萍乐坳陷区油气勘探提供参考。In order to understand the Wujiaping sedimentary environment in the Pingle Depression,elemental geochemical methods were used to study the contents and changes of various elements in the formations of wells YXZ02 and ZK2601 in the study area.The results show that the Sr/Ba ratio of the Guanshan section of the Leping Formation is smaller than that of the Laoshan section,indicating that the areas from Guanshan section to the Laoshan section have undergone a process of changing the water body from light to salty.It is inferred that a transgression occurred during this period.The contents of Ba,Ti,Fe,and Zn in the Guanshan section,Laoshan section,and Qibaoshan group of the Leping Formation gradually decreased,indicating that a process of decreasing source supply and slowing down the deposition rate happened in the Wujiaping period.The V/Cr ratio of the lower mudstone section and siltstone section of the Leshan Formation is higher than that of the upper sandstone section,and that the V/Cr ratio of the middle mudstone section of the Laoshan section is higher than that of the limestone section,both indicating that the reducibility of sedimentary environment of the former is stronger than that of the latter.The Zr content in Wujiaping decreased from early to late,reflecting that the sedimentary water body gradually deepened during this period.The research results can provide guidances for oil and gas exploration in Pingle Depression.

关 键 词：萍乐坳陷 吴家坪期 沉积环境 地球化学 元素 

分 类 号：P595[天文地球—地球化学]