从轮藻探讨南海北部大陆架的地层划分对比

根据南海北部大陆架18个钻井561个样品的分析鉴定,说明含有Characeae,Clavatoraceae和营养体三类轮藻。依据化石特征其地层时代为早、晚白垩世,古新世,渐新世和晚第三纪。其中早、晚白垩世和古新世地层的轮藻化石和岩性,可分别与广东陆地上,下白垩统官草湖群,上白垩统大塱山组及古新统(土布)心组和西(土布)组等对比,表明两者在白垩纪—古新世期间连为一体。恩平组沉积后隆升,自渐新世起南海北部大陆架逐渐沉降并形成今日南海。

STRATIGRAPHIC DIVISION AND CORRELATION OF THE NORTH PART OF THE CONTINENTAL SHELF OF THE SOUTH CHINA SEA BASED ON CHAROPHYTES

The author has analysed 561 microfossil samples from eighteen drill holes inthe north part of the continental shelf of the South China Sea, and has foundCharophytes, including Characeae, Clavatoraceae and Vegetives. Based on the fea-tures and distribution of the Charophytes, Lower Cretaceous, Upper Cretaceous, Pale-ocene, Oligocene and Neogene strata may be distinguished. Among other things,the charophytes and lithology of the Lower Cretaceous, Upper Cretaceous andPaleocene strata may be correlated with those of the Lower Gretaceous GuancaohuGroup, Upper Cretaceous Dalangshan Formation and Paleocene Buxin Formationand Xibu Formation in the continent of Guangdong Province. It is indicated thatboth were connected in the period from the Gretaceous to Paleocene, and havethe same or similar paleogeography and depositional euvironmend. After the EnpingFormation was deposited, the crust rose and then there occurred differentiation.The Pearl River delta no longer sank after the Lower Eocene Huayong Formationwas deposited, and the north part of the continental shelf of the South ChinaSea began to sink at the beginning of the Oligocepe until it formed the present-day South China Sea.