Generation Paleoenviromnent and Its Controlling Factors of Lower Cretaceous Lacustrine Hydrocarbon Source Rocks in Changling Depression, South Songliao Basin
Li Hao
Lu Jianlin
Li Ruilei
Wang Baohua
Xu Wen
Zuo Zongxin
Wang Miao
Liu Yazhao
Abstract：Heterogeneity study of lacustrine source rocks relys heavily on a deeper understanding of paleoenvironment and the major controlling factors on their formation.Based on element geochemical and petrological analyses of the paleoenvironment of the Early Cretaceous (from K1h to K1yc) in Changling depression.,the main controlling factors of organic source rocks development were analyzed according to the characteristics of its tectonics and sedimentary and the primary productivity of the source rocks in this study.Results show that from K1 h period to K1 sh stage to K1yc stage,Changling depression experienced paleo-water depth change from deep to shallow,palaeoclimate from humid-semi-humid to semi-arid,palaesalinity from fresh water to brackish water,and reduction condition from enhanced to weakened.From K1sh period to K1yc,the paleoenvironment of Changling depression shows obvious zonation;The correlation between trace element indexs indicating the paleoclimate and water reduction and TOC (Total Organic Carbon) of the source rock samples is significant,while the correlation between the trace element indexs indicating the paleosalinity and TOC of the source rock samples is small.So the paleoclimatic and redox conditions are the main environmental factors of the development of Lower Cretaceous lacustrine source rocks in Changling fault depression;K1 sh2 Formation high quality source rock which developed in equilibrium compensation stage,humid climate,hypoxia and high initial productivity is widely distributed.Followed by K1 sh1 Formation and K1 h 2 Formation,the organic source rock of K1yc Formation is relatively developed in the south and east,and the distribution is relatively limited.
Keywords：trace elementhydrocarbon source rockpaleoenvironmentmain controlling factorChangling depressionSongliao basinpetroleum geology
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 1774-1786 )