【摘要】 根据均衡原理制约的地热计算得到中国西部及邻区岩石圈的温度分布状态,以40、100km和莫霍面深度等温线图的形式表示,同时计算了以1 350℃等温面深度表示的中国西部及邻区的热岩石圈厚度。结果显示:中国大陆西北部地区、哈萨克斯坦东部地区以及上扬子地块、蒙古中西部地区和青藏高原中部的深部地温较低,青藏高原北部、东部以及天山褶皱带中部的深部地温高。在中国西部及邻区范围内,岩石圈厚度在180km以上的地区包括准噶尔盆地,塔里木盆地核心部位,西藏东部、中部以及祁连山地区。上扬子地块(四川盆地)岩石圈厚度为160km或更多,蒙古中西部地区以及哈萨克斯坦东部地区的岩石圈厚度为140～180km。青藏高原东部边缘和藏北地区以及天山中部吉尔吉斯伊塞克湖地区的岩石圈厚度较薄(<140km)。地热计算得到的结果与地震层析成像研究结果之间相互吻合。采用湿的上地幔流变学模型的计算结果表明,青藏高原及其东部边缘、天山褶皱带中部和蒙古中西部地区的岩石圈流变学强度模型为"奶油蛋糕(crèmebrlée)"型,其强度剖面显示强地壳而弱地幔的特点;上扬子地块(四川盆地)、准噶尔盆地、塔里木盆地和哈萨克斯坦东部地区岩石圈流变学强度模型为"果冻三明治(jelly sandwich)"型。更多还原

【Abstract】 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 brlée " 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.更多还原