| 青藏高原南北地体壳幔热结构差异的大地热流证据 |
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| HEAT FLOW EVIDENCE FOR THE DIFFERENTIATED CRUST-MANTLE THERMAL STRUCTURES OF THE NORTHERN AND SOUTHERN TERRANES OF THE QINGHAI-XIZANG PLATEAU |
| The average thickness of the crust reaches 70 km. in the Qinghai-Xizang Plateau, meanwhile the surface hydrothermal manifestations are widespread over the Himalayan Geothermal Belt. In addition, high heat flow was observed in South-Xizang, and the DSS, gravity and magnetic survey, as well as MTS all unanimously revealed a series of geophysical features of a warm crust. This compatibility of a thick yet warm crust in the Qinghai-Xizang Plateau fully evidenced geophysically has been once again proved by a N-S heat flow profile study, reflecting not only the peculiarity of the crustmantle thermal structure, but also the close genetic relation between the deep-seated formation process of such a specific thermal structure and the tectono-dymanic environment. Thus, the first step was forwarded towards the study on the unitary thereto- tectonic evolution of the Qinghai-Xizang Plateau. The N-S heat flow profile consists of the following 13 study areas：Pumuyiong Lake (n＝5，q=91 mW/m2)，Yangzhuoyiong Lake (n=4, q=146mW/m2),Luobusha(q= 60mW/m2), Northern Subburb of Lhasa (q=66mW/m2), Maqu(q＝106MW/m2), Yanbajing(q＝108mW/m2), Yangyingxiang (q= 3 64m W/m2 ), Laduogang(q＝338mW/m2），Naqu(q＝319mW/m2)，Lunbula ( n＝2，q＝140mW/m2），Tuotuohe (q＝47MW/m2)，Northern Foothill of Kunlun Mts. (q＝42mW/m2), and Xitieshan(q＝42mW/m2). The heat flow distribution pattern is noted with：（1) heat flow highs in South and lows in North, (2) stable in North and fluctuating in South, and (3) low heat flow belt affiliated to the Yarlung-Zangbo Suture Zone of bordering significance among the anomalously high heat flow regions in the south. Based on this pattern and considering the forms and boundary conditions of deformations and the heat source patterns (including shear-heating)of the different terranes, the whole Qinghai-Xizang Plateau can be divided into three parts: (1)cold united block of the four old teraanes in north with thick crust-thick lithosphere structure, (2) enormously squized-shortened hot Lhasa-Gangdise Terrane in the middle, accompanied by mufti-layered tectonically induced deep thermal activities of thickened crust-thinned lithosphere structure, and (3) overthrust-thickened warm Himalayan Terrane in south, accompanied by magmatic emplacement of anatectic type and crust-originated abnormal thermal structure of shearheating genesis. |
| SHEN Xian-jie,ZHANG Wen-ren,YANG Shu-zhen,GUAN Ye,JIN Xu.1990.HEAT FLOW EVIDENCE FOR THE DIFFERENTIATED CRUST-MANTLE THERMAL STRUCTURES OF THE NORTHERN AND SOUTHERN TERRANES OF THE QINGHAI-XIZANG PLATEAU[J].Acta Geoscientica Sinica,11(2):203-214. |
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