海南岛东方地区第四系原八所组地层归属再讨论

THE LATE PLEISTOCENE BASUO FORMATION IN THE DONGFANG AREA OF HAINAN ISLAND

根据海南岛东方地区地质调查最新成果,对《海南省岩石地层》晚更新世八所组层型剖面进行精细研究,通过6个钻孔剖面层序、粒度、重矿物、地球化学特征、碎屑锆石年龄数据峰值及与中更新统北海组的接触关系等特征,认为该地区八所组为陆相冲洪积沉积形成,其与北海组物源一致。因此东方地区的八所组与北海组实为同一套地层。应将东方地区原八所组归于北海组,从而导致整个海南岛地层格架发生变化。

As part of the ＂Lithostratigraphy of Hainan Province＂ project, we carried out a detailed study of the stratotype of the late Pleistocene Basuo in the Dongfang area in Hainan Province. We analyzed the se- quence stratigraphy, grain size distribution, heavy minerals, geochemical characteristics, detrital zircon geochronology of the Basuo Fm. at six drill cores, as well as the stratigraphic contact between the Basuo Fro. and the middle Pleistocene Beihai Fro. Our data show that the Basuo Fm. consists of continental dilu- vial deposits, and its sediment provenance is similar to that of the Beihai Fro. Thus, there is no difference between the Basuo and Beihai formations in the Dongfang area. They should belong to the same strati- graphic unit. This study provides a new stratigraphic framework for the Hainan Island.