Paleoclimate characteristics of the Paleogene Wenchang-Enping Formation in Wenchang B Sag,Zhusan Depression
Paleoclimate plays an important role in the production and preservation of organic matter and is crucial for the development of source rocks,while warm and humid paleoclimate conditions are generally considered to be conducive to the formation of high-quality source rocks.The Paleogene E2w and E2e are the most important source rock development intervals in Wenchang B Sag,Zhusan Depression,and the restoration of paleoclimate during their sedimentary period plays a crucial role in the selection of source rocks in the sag.In this paper,the paleoclimate characteristics of the sedimentary period are obtained by analyzing the palynological assemblage and the data of main and trace elements from well WB-1 and WB-2 mud and shale samples from Wenchang B sag.The characteristics of palynological assemblages indicate that the climate of source rocks from E2w-E2e formation in the depression was tropical-subtropical and semi-humid.Among the main trace elements,the paleoclimate sensitive elements Sr/Cu and CIA further confirmed the characteristics of warm and humid climate in this period.In particular,the Mn/Mg and Rb/Sr ratios emphasized that the climate conditions in the deposition period of the second member of the E2w2 were the most warm and humid.Therefore,the deposition period of the second member of the E2w2 is considered to be the best period for the development of high-quality source rocks in Wenchang B Sag.
Zhu Ⅲ DepressionWenchang B SagPaleogenepaleoclimatehigh-quality source rocks
NETL
NSTL
万方数据
