Abstract:

Gravity and magnetic survey on the scale of 1:100000 is made in the East China Sea and a lot of geological informations were obtained by the first Brigade of Marine Geological survey.Based on the analysis of gravity and magnetic anomaly and the comprehensive interpretation of geological,seismic and drilling data of both continent and Islands,the authors consider that the average Bouguer anomaly in a broad range revealsthe slow uplifting of the Moho and the thinning of the crust from west to east in the East China Sea.The average Moho depth of continental shelf is 30km.The changes of gravity and magnetic anomaly and their strike show that the formationstages of the basement in the studied area progres sively turn younger from northto south and from west to east,i.e.,from the Precambrian to the Pre-Mesozoicand then to the Pre-Miocene.The shapes and distribution regularities of localgravity and magnetic anomaly indicate that the fault stages and volcanic activitiesfrom northwest to southeast have a new tendency of changing from old toyoung,and the regional tectonic framwork contains 3 uplifts and 2 basins,fromwest to east including Zhejiang-Fujian uplift zone the East China Sea shelfbasin,Diaoyu Island upwarping folded zone,Okinawa Trough basin and RyuKyu Archipelago upwarping folded zone.