Tanggu district lies 45km in the east of Tianjin,border on the Bohai sea in the east. It’s 50kin long from,south to north and 25kin wide from east to west,the total area is 802.8kin~2. It’s a place where the Tianjin Economic and Technological Development Zone is located, and an important frade port in the north of China.The terrain of this area is smooth,the ground height is about 1-3m. It mainly contains Haihe river water system whose upper reaches are mainly for storing water, and the lower reaches,for developing the shipping business.This area which is a littoral deposit environment lies in the North-east of North-China plain subsidence area of the second subsidence zone of New Huaxia structure system.In this area,the formation of Mesozoic group is universal non-existance, the Upper Teritiary system directly overlies the Lower Palaeozoic group basement. The formation of Quaternary system is a parallel discordant contact with the underlying Upper Teritiary system,the depth of its bottom boundary is 500
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