上海市15-17ka.BP.的古地貌与工程地质条件

编制了100m以浅多幅地质剖面图和30ka.BP.以来多个时段的古地理图。这些图件清楚地反映出在于25－24.5ka.BP和17－15ka.BP的低海面时期，地面曾经历过两次强烈的侵蚀切割。本文着重分析研究埋深60m以浅各陆相粘性土层（俗称暗绿色粘土或硬粘土层）的成因、时代、空间分布和17－15ka.BP间的古叶貌格局及其与工程地质分区的关系。

Palaeo-geomorphology and Its Engineering Geological Significance During 15 - Ka. B. P. In Shanghai Urban Area

According to the data of more than 2000 engineering bore cores and experimental result of over 20 representative bore cores, sedimentary environment and spatial distribution of the shallow Quaternary stratum ( <60m) .especially several continental caly or subclay bands, we drew up several maps of geoglogical sections and the paleoland map( 1 :50000) during 15 - 17Ka. B. P.. It is discovered that there are great difference between the landform during 15 - 17Ka. B. P. and modern landform. During 15 - 17Ka. B. P. , there were two old rivers. One lies in the west and flows the south,while the other lies in the urban area and flows the east. Due to the cutting of the two rivers,a large platform is formed and 2 -3terrace s are found along the rivers. This sort of paleolandform structure determines the later sedimentation and stratum structure of different landform units. Thus,the spatial distribution of 60m Quaternary strata and their engineering geoglogy condition becomes very complicated. According to paleolandform distribution and stratum structure difference, the authors compiled a map of different area of engineering geoglogy (1: 50000). It discussed the geotechnical geological conditions of natural area and three stub foundation areas and important problems in application . We hope the study will play an important role in the engineering survey, desitgning and construction in Shanghai area.