Distribution Pattern of Terrestrial Heat Flow in Bohai Bay Basin, North China

New temperature data from wells in Bohai bay basin increasing associated with the enhancement of oil and gas exploration there provides more reliable information about studying on Terrestrial heat flow pattern. Based on the data from 88 systematic continuous temperature logging curves and more than 1000 well test temperature data, along with the corresponding thermo-physical parameters of rock samples, here we determined 53 heat flow data and estimated other 172 according to thermal resistance method, then the distribution Pattern of heat flow in Bohai Bay basin is presented. Heat flow in Bohai bay basin is relatively large than those in the surrounding mountain areas. For instance, heat flow of Yanshan, north of the basin, is only low as 25 ~ 54 mW/m2, and less than 50 mW/m2 for Taihang mountain to the west, the average heat flow of Luxi Uplift is about 54 mW/m2. Crustal thickness of regions outside the basin to the west and north approximating to 36~44km, apparently is larger than that of basin, which maybe accounts for the high heat flow in Bohai bay basin. Those regions of relatively thin crust within the basin are of middle-high heat flow. Heat flow in such depressions as the Lower Liaohe, Bozhong, Jiyang and Yongqing area northeast of Jizhong Depression, together with Bohai offshore, for example, are all larger than 64 mW/m2, and even high as 70 mW/m2 for some regions with mantle upwelling. Low heat flow appears in those areas with relatively thick crust. For instance, heat flow in Linqing Depression, southwest margin of Jizhong Depression and southern Huanghua Depression, are all less than 64 mW/m2, even less than 60 mW/m2 for those areas with mantle downwelling. Heat flow pattern in Bohai Bay basin is negative correlation with crustal thickness, for those regions with relatively crustal thinning, heat derived from the deep earth is more due to the large lithospheric extension, resulting in the high heat flow; while for those with crustal thickening, heat flow is relatively low owing to small heat from earth interior. Mantle upwelling and crust thinning associated with episodic lithospheric extension in Bohai Bay basin formation, results in deep magma¡_s intrusion into shallow crust and/or eruption into surface, which accounts for the high heat flow background of basin. Bohai Bay Basin is now continuing to subside, along with the heat attenuation process due to not achieving the heat balance.