Causes of Geothermal Fields and Characteristics of Ground Temperature Fields

Abstract

There are many arguments on energy sources and main controlling factors of geothermal fields, so a systematic study on the distribution of ground temperature fields shall be necessary. In this paper, the cooling rate of abnormal heat source and the heat transfer of paleo-uplift model are simulated by using the forward heat conduction method of geothermal field. Combining with a large number of geothermal field exploration examples, the following conclusions are drawn: 1) The magmatic activity has no direct contribution to the modern geothermal field when the time of magmatic activity is more than 0.5Ma, and Tengchong and Qinghai-Tibet regions, which are most likely to have modern magmatic activities in the mainland of China, had their magmatic activities 0.5Ma years ago; 2) The temperature of most geothermal fields can be obviously divided into three sections from shallow to deep: high geothermal gradient (H), low geothermal gradient (L), and low temperature (D). Temperature contours on the profiles are mirror reflections, indicating that heat transfer is dominated by heat conduction, rather than by "heat sources" with abnormal high temperatures, which provide heat for geothermal fields. 3) Physical property difference (thermal conductivity) of near-surface (0-10km) strata is the main controlling factor of geothermal field.