塔里木盆地岩石圈热-流变学结构和新生代热体制  

Lithospheric Thermo-Rheological Structure and Cenozoic Thermal Regime in the Tarim Basin,Northwest China

作　　者：刘绍文[1] 王良书[1] 李成[1] 张鹏[1] 李华[1] 

机构地区：[1]南京大学地球科学系

出　　处：《地质学报》2006年第3期344-350,共7页Acta Geologica Sinica

基　　金：国家"973"重点基础研究发展规划项目(编号G1999043302);中国博士后科学基金(编号2004036411);江苏省首届博士后创新基金资助成果

摘　　要：塔里木盆地是我国特大型沉积盆地，也是“西气东输”工程的重要战略基地。利用盆地区大量的地温及岩石热物性参数并结合地热学知识分析了塔里木盆地的现代地温场、热演化和岩石圈热-流变学结构，并进一步讨论了地热场和岩石圈性质对成盆、成烃和成藏的意义。研究结果表明塔里木盆地现今平均大地热流为45mW／m^2，平均地温梯度为18～20℃／km；整体上具有低温冷盆的特征。地温场的展布具有明显的横向差异，不同构造单元的地温场特征相差较大：坳陷部位具有较低的地温，隆起区具有较高的地热特征。热演化模拟表明盆地自成盆以来经历了从震旦纪—奥陶纪高热流（“热”盆）、志留纪—晚古生代热衰减（“热”盆向“冷”盆过渡）、中生代稳定的热演化（低热流“冷”盆阶段）、新生代岩石圈挠曲热演化等阶段。“热”岩石圈厚度为205～230km，有效弹性厚度（Te）达66±7km，脆-韧性转换深度为25～28km，岩石圈总强度为1．6×10^13～7．8×10^13N／m。盆地区的岩石圈表现为地温低、强度高的刚性块体，具有整体变形特征。受印度-欧亚大陆碰撞的远程效应影响，塔里木盆地作为刚性块体进行应力传递，盆地周边产生强烈变形，表现山脉的急剧隆升和盆地边缘的快速挠曲沉降。这一动力学过程造成地层内部流体趋于流向山前隆起带，并对油气成藏和分布具有重要的控制作用。As one of super-large-scale sedimentary basins in China, the Tarim Basin is also a strategic base for the ＂ natural gas transportation from west to east＂ project. Integrating abundant data of geotemperature and rock thermophysical parameters collected in the basin with corresponding geothermal modeling, here we present the characteristics of geotemperature field, thermal evolution and lithospheric thermo-rheological structure of the basin, along with the implications for the formation and alternation of basin, hydrocarbon and reservoir. Our results show that the average present-day heat flow of the basin is 45 mW/m^2 and 18 ～ 20 C/km for geotemperature gradient, and the basin is characterized by lower temperature and relatively cold in a whole. Lateral heterogeneities exist for the distribution of geotemperature field in the basin. The structural units of the basin differ much in the geothermal features, and generally, the depression areas are of relatively low geotemperature while high for uplifts and highs in the basin. Thermal evolution modeling of the basin indicates that it has experienced four different stages since the basin formation as follows： high heat flow stage from the Sinian to Ordovician （＂hot＂ basin）, thermal attenuation stage during the Silurian to late Paleozoic （transition stage from ＂hot＂ basin into ＂cold＂ basin）, then stable thermal evolution stage in the Mesozoic （＂cold＂ basin with low heat flow）, and flexural deformation of lithosphere in the Cenozoic. The ＂thermal＂ lithosphere of the Tarim Basin is 205～230 km, and the effective elastic thickness of the lithosphere is 66～7 km, along with 25 ～28 km for the crustal brittle-ductile transition depth; the total lithospheric strength is 1.6×10^13～7.8×10^13N/m. The lithosphere beneath the basin is characterized by rigid block with low temperature but large strength, and deform in a whole. Responding to the far field effect of the India-Eurasia collision, the Tarim Basin transferred the collisional

关 键 词：大地热流 岩石圈热-流变学结构 热体制 地球动力学 塔里木盆地 

分 类 号：P618.13[天文地球—矿床学]