珠江三角洲晚第四纪沉积特征

THE SEDIMENTATION CHARACTERISTICS OF ZHUJIANG RIVER DELTA IN LATE QUATERNARY

本文主要研究珠江三角洲的第四纪地层;晚更新世玉木亚间冰期、全新世中期(大西洋期)海侵阶段的地貌景观及珠江三角洲晚第四纪以来的沉积形成过程。

The Quaternary strata in the Pearl River Delta can be divided into two stratigraphic formations, the Zhongshan Formation in late Pleistocene, and the Shunde Formation in Holocene, each of which is subdivided into the upper, middle and lower members.The landscape is characterized by monadnock-errosive platformalluvial plain-submerged valley bay in the trans-gressive stage of Wiirm subglacial period in late Pleistocene. In the transgressive period of the middle Holocene (Atlantic Period), the land features were that the monadnocks and islands were scattered in the whole region with surrounding low hills, and a large area was occupied by estuarine bays except for the bordering areas covered by alluvial plains. In the areas of Shajiao and Shunde and near Zhongtang of Dongguan, two bayhead deltas were present. These features control the characteristics and distribution of the sediment of late Quaternary.The formation process of the Pearl River Delta since late Quaternary can be divided into six stages through two late major transgressions (about 27000 QBP and 7500 QBP)and one earlier major regression (21 000-15 000 QBP). The sedimentary model during late Pleistocene was a 8acustrine and transgressive submerged-valley-bay model, whereas in Holocene it was a fluvial-tidal-controlled complex bay-filled delta model.