A critical review on the occurrence of and its implications of natural hot springs in continental China

Abstract

Hot springs are surface displays of the Earth's internal heat as it travels through the lithosphere. Here, we reviewed the occurrence of hot springs in continental China. We choose seven typical places, including the Yangbajing area, the Taxkorgan area, South China, North China, Guanzhong basin, Gonghe-Guide area, Chuan-Dian (east Tibet plateau) area, to decipher the implication of the occurrence of hot springs. A comprehensive study of topographic features, characterization of faults, seismic catalog, GPS velocity field, and total strain rate shows the first order controlling factors of the occurrence of hot springs are the active faults, water pressure, and deep cycling. The relationship between hot springs distribution and deep thermal background, including thermal lithospheric thickness, Moho discontinuity, lithospheric structure, and Curie point isotherm, was examined. The results show that the deep thermal background can be used as a secondary factor to control the distribution of hot springs. The role of caprock is relatively limited except of the granite distribution area of South China. In South China, the caprock overlying high heat-producing granite can generate hot springs under the presence of water pressure. Further, the distribution of hot springs is strongly coupled with the lithospheric/crustal extensional region, implying a relationship between stress-released area and the occurrence of hot springs. Such a relationship can be used to interpret the tectonic evolution of continental China since the Cenozoic era. Moreover, by integrating the factors of hot spring distribution, we can comprehensively predict the occurrence of hot springs.