Thermal State and Rheological Strength of the Lithosphere beneath Western Part of China and Its Adjacent Region
详细信息
- 责任者：Wang Yang (School of Earth Sciences and Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Cheng Suhua
- 刊名：Earth Science Frontiers
- 出版年：2013
- 卷期：20(1)
- 关键词：岩石圈 ; lithosphere ; 地热场 ; geothermal fields ; 中国 ; China
- 页码：p.182-189
- 图表：illus., 48 refs.
- 分类号：0400
- issnNo：ISSN1005-2321
- isbnNo：CN11-3370/P
摘要
Lithospheric temperatures beneath the western part of China and its adjacent region were estimated by local isostasy equilibrium-constrained geothermal calculation in this study.Maps of the lateral temperature variation at depths of 40100km and Moho boundary are presented for the western part of China and its adjacent region,and meanwhile,the thermal thickness of the lithosphere is calculated as represented by the depth of 1350℃isotherm.The results show that the temperatures at depth are low in the northwestern part of China continent,and the eastern part of Kazakhstan and Upper Yangtze massif(Sichuan Basin),as well as in central and western parts of Mongolia and the central part of Tibetan plateau,but those are high in the northern and eastern parts of Tibetan plateau as well as the middle segment of Tianshan orogenic belt.Among China continent and its adjacent region,lithosphere is thicker than 180km beneath the Junggar Basin,the core part of Tarim Basin,and the eastern and central parts of Tibetan plateau,as well as the Qilianshan region;and it is 160km or more under the Upper Yangtze massif;however,the thickness of lithosphere in the central and western parts of Mongolia,and the eastern part of Kazakhstan is in the range of 140km to 180km.Lithosphere is thinner beneath the eastern margin and northern part of Tibetan plateau,as well as Issyk Lake of Kirghiztan in the middle segment of Tianshan orogenic belt(<140km).These geothermal modeling results are in good agreement with those of seismic tomography.Using the wet mantle rheology to represent the mechanical behaviour of upper mantle,it is found that the " crème brlée " model,i.e.,a strong crustal portion but a weak lithospheric mantle portion in vertical strength profile,approximates the lithospheric rheology for Tibetan plateau and its eastern margin,the middle segment of Tianshan orogenic belt,and the western and central parts of Mongolia.On the other hand," the jelly sandwich " model demonstrates the lithospheric mechanical strength of the Upper Yangtze massif(Sichuan Basin) and that of Junggar,Tarim Basins,and the eastern part of Kazakhstan.