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Basic Characteristics of the Earth's Temperature Distribution in Southern China
Author(s) -
Jun Wang,
Shangyao Huang,
Geshan Huang,
Jiyang Wang
Publication year - 1986
Publication title -
acta geologica sinica‐english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 0001-5717
DOI - 10.1111/j.1755-6724.1986.mp60003008.x
Subject(s) - geothermal gradient , china , borehole , geology , latitude , hydrogeology , chine , distribution (mathematics) , geomorphology , geography , paleontology , archaeology , geodesy , geotechnical engineering , mathematical analysis , mathematics
Sourthern China referred to in this paper embraces all the provinces to the south of latitude 32° N within the territory of China, exclusive of Tibet and Taiwan. The paper is based on the data obtained from temperature measurements of 680 boreholes drilled for petroleum, coal and hydrogeology. The depth of these boreholes ranges between 1,000 and 2,000 m in most cases, being generally not less than 400 m and reaching 7,000 m in maximum. Through the elaboration and analysis of the temperature data, isotherm maps showing the temperatures at depths of 1,000 m, 2,000 m and 3,000 m respectively and a geothermal gradient map of southern China have been compiled. These maps indicate that the earth's temperature distribution in southern China is characterized by a relatively low value in areas of its central part and those to the west of the Anning River valley of the western part (30°C, 40°C and 70°C at depths of 1,000 m, 2,000 m and 3,000 m respectively), and a comparatively high value in the southeastern coastal areas and western Yunnan (60°C, 80°C and over 120°C respectively), and that the geothermal gradient also increases from less than 1.5°C/100 m in the central part towards both the east and the west to 2.0‐3.0°C/100 m or even over 4.0°C/100 m. The earth's temperature distribution is strictly controlled by the deep structure of the earth's crust and is very closely related to the character of the regional geological structure. The stable central areas remarkably differ in the earth's temperature distribution from the tectonically active areas such as the southeastern coastal areas and the Jinggu‐Tengchong area in western Yunnan, the former being Jower than the latter. Meanwhile, due to the well‐developed karst features in southern China, the strong groundwater flow may exert certain cooling effect on the temperature down to a depth of about 1,500 m. According to the regularity of the earth's temperature distribution, regional deep structure of the earth's crust, regional geological structure and hydrogeological conditions, the following four models are proposed to explain the mechanism of formation and distribution of the earth's temperature fields in southern China: 1) conduction type; 2) convection type; 3) deep heat‐source conduction‐convection type; and 4) precipitation infiltration cooling type.