广西百色盆地古近系沉积特征及其古气候意义

Paleogene Sedimentary Characteristics and Their Paleoclimatic Implications in the Baise Basin,Guangxi

通过研究广西百色盆地地表斩龙颈剖面、百东河剖面、六吜剖面、那周剖面记录的沉积特征、沉积标志、粘土矿物组合类型及CaCO3指数的古气候信息,再结合ESR测年数据,确定了古近系古新统晚期六吜组一始新统晚期百岗组(63.1～33.7MaBP)地层时间序列,反应该区自晚古新世至始新世晚期气候由半干早、干旱—潮湿(偏凉)—温暖潮湿—潮湿(偏热)—温暖潮湿向偏干转化的6个古气候演变阶段。

Four exposed sections at Zhanlongjing, Baidonghe, Liuniu and Nazhou were investigated in the Baise basin, Guangxi. Paleoclimatic information was gained based on the sedimentary characteristics and criteria, clay mineral assemblage types and CaCO3 index recorded by these sections. Then according to the paleoclimatic information, combined with the ESR dating data, the time sequence for the sediments of the late Paleocene Liuniu Formation to late Eocene Baigang Formation （63.1-33.7 Ma BP） was determined, which indicates that in the study area there occurred six paleoclimatic evolution stages, i.e. the semi-arid and arid, humid （slightly cool）, warm-humld, humid （slightly hot）, warm-humid and slightly arid stages, from late Paleocene to late Eocene.