摘要
从第四纪地层划分、环境、构造活动、近现代洞庭湖构造沉降特征与发展趋势等方面,介绍了洞庭盆地第四纪地质研究现状。前人对洞庭盆地及其周缘地区分别建立了覆盖区和露头区第四纪地层系统,其中覆盖区第四纪下限年龄达3Ma左右。不同研究者对第四纪气候演化和全新世以来的气候与环境演化的认识存在程度不一的差异。对洞庭盆地周缘网纹红土的成因存在水成和风成两种不同观点。对盆地构造活动存在断陷、坳陷、先断陷后坳陷以及其他多种不同观点。对于构造因素和非构造因素对现代湖泊的控制作用存在不同看法。在洞庭湖未来演变趋势方面,由于研究问题的角度不一致,有的认为洞庭湖会逐渐加深扩大,有的认为不久将萎缩消亡。重复水准测量资料对比显示近现代洞庭湖构造沉降速率为3～10mm/a;而沉积速率法计算的晚更新世以来的平均沉降速率为0.06～0.25mm/a,局部为0.62mm/a。最后提出洞庭盆地第四纪地质今后研究的主要方向是气候演化的多指标约束、各次级构造单元构造-沉积特征的详细解剖、覆盖区晚更新世—全新世沉积特征的精细调查以及洞庭湖现代沉降特征的GPS监测等。
This paper introduces the status of Quaternary geology research about Quaternary strata,environment,tectonic movement and origin of modern lakes of Dongting Basin,and subsiding features and evolutional tendency of the lake.The Quaternary stratum systems of cropped areas and covered areas in Dongting Basin and its periphery had been set up,in which the age of floor Quaternary deposits in covered areas is about 3Ma.However,opinions vary about the cognitions of Quaternary and Holocene climatic and environmental evolution.About the origin of the vermicular red earth around the basin,some believe it should be from aqueous sediments,but others consider it from aeolian sediments.Also different ideas are proposed about the characteristics or tectonic activities of Dongting Basin in the Quaternary.For example they should be faulted,or depressional or early faulted-late depressional.Some people emphasize notectonic factors,some stress tectonic factors and while others emphasize notectonic and tectonic factors to-gether about the origin of modern lakes.Some people hold that Dongting Lake will deepen and expand, while others believe that the lake will soon shrink and wither away.The modern subsidence rate of Dongting Lake is 3～10mm/a according to double leveling,while the average subsidence rate since Late Pleistocene was 0.06～0.25mm/a with 0.62mm/a in locality according to sediments.As a summary,the paper points out the future research trends of Quaternary geology of Dongting Basin such as multiple indexes constraint on the climatic evolution,detailed studies on the tectonic-sedimentary features of every sec-ondary tectonic units,careful research on the Late Pleistocene-Holocene sediments of cropped areas and GPS monitoring about modern tectonic subsidence of Dongting Lake.
出处
《地质科技情报》
CAS
CSCD
北大核心
2010年第5期1-8,14,共9页
Geological Science and Technology Information
基金
中国地质调查局地质大调查项目(1212010610706)
国家自然科学基金项目(40771213)
关键词
洞庭盆地
第四纪
地层
环境
构造活动
湖泊成因
沉降速率
Dongting Basin
Quaternay
stratum
environment
tectonic movement
origin of lake
subsid-ence rate
