中国及相邻海域地温场分布规律的研究
GEOTHERMAL FIELD DISTRIBUTION IN CHINA AND ADJACENT SEA AREAS
-
摘要: 引言地温场是地球物理场的组成部份,地温场信息从一个侧面反映了地球的物理特性。近年来,不少学者从不同方面,不同程度地对我国陆地和海域,以及东部邻区的地温场性质和地质意义进行过研究,已积累了一些地温场资料。为了对中国及相邻海域的地温场分布特征有一总体的认识,我们试图对目前所获得的各种地热信息进行综合分析。为了便于讨论,参考上述发表的国内外文献,收集了某些煤田、油气田和部份省市的地温资Abstract: On the basis of measurements of the temperatures of hot springs,earth surface and wells and heat flow in lakes and seas, a geothermal field information map of China and adjacent sea areas have been compiled.In the map China is di vided into eight geothermal regions.According to these data combined with related geophysical data, some views are proposed about the geothermal field distribution and evolution of crustal structure. A lot of geotherma activities and high heat flow values show that the crust of the Xizang(Tibet)geothermal region is in a hot state,with local shallow molten masses.Absorption of seimic waves,negative magnetic anomalies and MT anomalous zones at depths of 10—20km all support the hypothesis. The North China geothermal region is large Meso—Cenozoic subsidence basin.As it experienced a rift development stage,its local geothermal background is higher.Local hot points appear at places where the crust becomes thin and Ourie isothermal surface becomes shallow. The crust of the Taiwan and East China Sea geothermal is fairly thin(20—30)km and fractures are well developed.This faciliates the ascent of hot fluids and gives rise to middle-low temperature hydrothermal activity. The heat flow data from the South China Sea(average 2.08 HFU)show that there is no subduction zone between the continental slope and the deep sea basin and that in stead passive continental margins may possibly exist. Greadual thickening of China’s crust from east to west may explains a decrease in geothermal gradient from east to west. In the end the paper discusses the relationships between the geothermal regions and the development of geothermal resources and oil prospects.