莱州湾东部滨海水域第四纪沉积及古地理特征
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摘要
本文通过对６个钻孔和４６ｌｋｍ浅层地震剖面测量获得的测年、微古、孢粉、藻类、古地磁以及岩性特征和地震反射界面等资料的综合分析，将本区第四系划分为中更新统、上更新统和全新统，对各时期的沉积特征进行了较详细的阐述，并对不同时期的沉积相特征和古地理环境的变化进行了初步地揭示。
Quaternary in the study area is divided into Middle Pleistocene,UpperPleistoceneand Holocene according to the comprehensive analyses on the collected 6 drilling coresand 46lkm-shallow seismic profile,The Middle Pleistocene and Upper Pleistocene main-ly consist of continental sediments made up of multicyclic alluvial-pluvial materials. TheUpper Pleistocene is locally intercalated with supralittoral sediments. The Holocene ismainly composed of continental(or supralittoral),inner sublittoral,intertidal andsupralittoral sediments. From EarlyPleistocene to early MiddlePleistocene,the study area didnot receivesediments andwas subjectedto denudation,From the earlt time of the Middle Pleis-tocene,the area had alluvial sediments accumulated in the intermontane valleys andsmall basins. Up to the Late Pleistocene, the study area became a part of the piedmontalluvial plain in the north of the Jiaodong Peninsula,Due to the increase in the differ-ences of neotectonism,the plain and intermontane basin areas were subsiding continu-ously and multicyclic alluvial accumulation of 20-30m thick was formed.During the peri-od of the Cangzhou transgression(the last interglacial),the sea level rose to the positionnot far from the study area,Therefore,local continental alluvial sediments containsupralittoral sediments with foraminifera fossils. At the early time of Holocene,the sealevel reached the present-14m position and the study area was still a land environ-ment.And up to the Middle Holocene,sea water reached the present 5m depth- contourposition,and a set of inner sublittoral and intertidal sediments were developed.From theend of Middle Holocene to the beginning of Late Holocene,the sea water began to re-treat,and the above- mentioned inner sublittoral and intertidal sediments were graduallycovered by alluvium,forn1ing the small piedmont alluvial plain in the north of theLaizhou Bay.
Quaternary in the study area is divided into Middle Pleistocene,UpperPleistoceneand Holocene according to the comprehensive analyses on the collected 6 drilling coresand 46lkm-shallow seismic profile,The Middle Pleistocene and Upper Pleistocene main-ly consist of continental sediments made up of multicyclic alluvial-pluvial materials. TheUpper Pleistocene is locally intercalated with supralittoral sediments. The Holocene ismainly composed of continental(or supralittoral),inner sublittoral,intertidal andsupralittoral sediments. From EarlyPleistocene to early MiddlePleistocene,the study area didnot receivesediments andwas subjectedto denudation,From the earlt time of the Middle Pleis-tocene,the area had alluvial sediments accumulated in the intermontane valleys andsmall basins. Up to the Late Pleistocene, the study area became a part of the piedmontalluvial plain in the north of the Jiaodong Peninsula,Due to the increase in the differ-ences of neotectonism,the plain and intermontane basin areas were subsiding continu-ously and multicyclic alluvial accumulation of 20-30m thick was formed.During the peri-od of the Cangzhou transgression(the last interglacial),the sea level rose to the positionnot far from the study area,Therefore,local continental alluvial sediments containsupralittoral sediments with foraminifera fossils. At the early time of Holocene,the sealevel reached the present-14m position and the study area was still a land environ-ment.And up to the Middle Holocene,sea water reached the present 5m depth- contourposition,and a set of inner sublittoral and intertidal sediments were developed.From theend of Middle Holocene to the beginning of Late Holocene,the sea water began to re-treat,and the above- mentioned inner sublittoral and intertidal sediments were graduallycovered by alluvium,forn1ing the small piedmont alluvial plain in the north of theLaizhou Bay.
引文
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