摘要
长江口区因古地形的差异和海平面的变动在地质时期形成不同的沉积环境。根据微古分析,综合岩性,孢粉、测年等资料研究,晚第四纪以来,本区古地理经历了5个阶段:1.末次冰期亚间冰期(35000—25000年前)为海相和过渡相沉积;2.末次冰期晚期(20000—15000年前)本区普遍为河、湖相沉积;3.冰后期早期(14000—10000年前)气候转暖、海面上升,本区海侵各处不一;4.冰后期中期(10000—7000年前)气候湿暖,河口湾达到最大范围;5.冰后期晚期(7000年前—现代)三角洲发育阶段,属河口相环境。
There are a variety of sedimentary environments changing with time in Yangtze Estuary area due to its changeable paleotopography and fluctuation of eustatic sea level. The paleogeographic evolution of Yangtze Estuary since the Late Quaternary has involved 5 stages according to the data on micropaleontology, lithology, palynology, and dating: 1. During the sub-inter-glaciation in the Lastest Glaciation(35,000-25,000 yrs. B.P.), after the Pseu-dorotalia Transgression, this area changed basically into marine and transi-tional facies; 2. In the late stage of the Lastest Glaciation with a lower sea level(20,000-15,000 yrs. B.P.)the climates were cold and dry and this area is interpreted as a fluviolacustrine facies; 3. The early post-glaciation(14,000-10,000 yrs. B.P.)is characterized by the global warming and rapid eu-static sea level. The transgression reached this ancient valley with various facies in different parts; 4. During the middle of post-glaciation(10,000-7,000 yrs. B.P.)climates warmed and wetted and the Yangtze Estuary exten-ded itself to the maximum; 5. In the late post-glaciation(7,000 yrs. B.P. recent), the Yangtze Delta started to set up and the delta plain extended itself towards the sea rapidly. The estuarine facies predominated the whole area.
出处
《同济大学学报（自然科学版）》
EI
CAS
CSCD
1992年第4期459-466,共8页
Journal of Tongji University:Natural Science
基金
国家自然科学基金
关键词
长江口
晚第四纪
微体古生物
Yangtze Estuary
Late Quaternary
Paleogeography
Micropaleonlology
