江汉盆地第四纪地质研究现状

Status of Quaternary Geology Research of Jianghan Basin

从第四纪地层、环境、构造活动、现代湖群成因等方面,介绍了江汉盆地第四纪地质研究现状。针对江汉盆地及其周缘地区已分别建立了覆盖区和露头区第四纪地层系统,其中覆盖区第四系下限年龄达3 Ma左右。不同研究者对第四纪气候与环境演化的认识存在程度不一的差异。基于江汉盆地周老镇钻孔第四纪沉积的砾石特征、重矿物组成及磁学特征的研究表明,长江贯通三峡的时间为1.1 Ma左右。对盆地构造活动存在断陷、坳陷以及其他不同观点。对全新世暨近现代区域主压应力有NE-NNE向和NW向2种不同认识。对于现代湖泊或湖群的成因,或强调非构造因素,或强调构造因素,或认为构造与非构造因素均起到重要作用。最后提出江汉盆地第四纪地质今后研究的主要内容是第四纪气候与环境演化、盆地凹陷区边缘第四系厚度变化特征、覆盖区晚更新世-全新世沉积物的精细调查以及现代江汉盆地升降特征的GPS监测。

This paper introduces the research of Quaternary geology in Jianghan Basin in its Quaternary strata,environment,tectonic movement and origin of modern lakes and the establishment of the Quaternary strata systems of both outcropped and covered in the basin and its periphery areas,in which the floor Quaternary deposits in covered areas are about 3 Ma.It also presents the varying cognitions of Quaternary climatic and environmental evolution among different researchers concerned.The studies on the gravels,heavy minerals and magnetic fabric of the deposits in Zhoulaozheng borehole suggest that the formation age of the Three Gorges is about 1.1 Ma.Some studies propose viewpoints of faults and depressions about the tectonic activities during the Quaternary in the basin.Two different understandings are found about the regional major pressure stress during Holocene or modern period such as NE-to NNE-trending and NW-trending.Some people emphasize no-tectonic factors,and others emphasize tectonic factors and while others emphasize no-tectonic and tectonic factors together about the origin of modern lakes.In the end,the paper puts forward future research trends of Quaternary geology of Jianghan Basin such as Quaternary climatic and environmental evolution,changes of the Quaternary sediment width on the margin of the basin,the further study of the Late Pleistocene-Holocene sediments of cropped areas and GPS monitoring about modern tectonic subsidence of Jianghan Basin.