【摘要】 本文依据红海湾浅层地震和四个钻孔资料,研究调查区第四纪沉积特征,划分为四个层组和五套沉积物,指出本区晚更新世以来至少经历过两次海侵和一次海退.更多还原

【Abstract】 Plenty of data have been obtained using geophysical approach combining with drilling in survey of Quaternary sediments in Honghai Bay, Guangdong Province,Shallow seifiles profiles clearly show four reflected units of loose sediments: Unit I, II, III and IV from top to bottom with total thickness of 18-70m. The Quaternary deposits can be divided into five layers: The bottom of Unit IV is yellow sand and gravel; The middle and upper parts of Unit IV and the lower part of Unit III are grey silty mud; The upper part of Unit III is particoloured piebald clay; and Unit II and Unit I are sandy sediments and grey argillaceous silt respectively. C14 dating indicate that the fifth, fourth and third layers are late Miocene, and the second and first layers are Holocene.Two transgressions and one regression occured in the Quaternary in the Honghai Bay. The Bay was exposed as land about 28,000?0,000 years ago, with the sediments dominated by !coarse diluvial elastics. After 28,000 years BP, sea water invaded into the southern part of this region, estuarine fine deposits accumulate there. The sea water retreated from this region during Wtirm-glaciation, then terrigenous piebald clay deposited. The sea level rose again and arrived at the area Which recent depth is about 15m approximately at 8,000 years ago, then stopped over at the level for a short period, and coarse grained littoral sediment was deposited. The sea level continued to rise about 6,000 years B.P. and reached the present position about 2,500 years B.P..更多还原