吐哈盆地西南部热演化史

根据镜质体反射率、抱粉色变指数、自生粘土矿物等地温指标的研究，表明从晚古生代至新生代吐哈盆地西南部的古地温梯度是逐渐降低的，地温场是逐渐变冷的。二叠纪至三叠纪时，托克逊凹陷的古地温梯度为6．18～6．58℃／100m，都南凹陷为4．07℃／100m。诛罗纪时前者仍高于后者，但其值不会高于3℃／100m，鲁酉凸起略低。今地温梯度具有东高西低的特点，且随深度的变化具不均一性，这可能与古地温及岩性有关。根据温度欠补偿原理计算出来的地层补偿厚度并不完全等同于地层剥蚀厚度。据分析，三叠纪末二者大致相当，地层剥蚀厚度可达千余米。

GEOTHERMAL EVOLUTION HISTORY IN THE SOUTHWEST TUHA BASIN

According to the paleogeothermal scales of vitrinite reflectance, sporopollen colorindex and authigenic clay mineral, the research indicates that the geothermal gradient is decreasing, and that the geotemperature field was colder and colder from the Late Paleozoic to Cenozoic. During Permian--Triassic, the paleogeotemperatural gradient was 6. 18-- 6. 58 oC /100m inTokesun depression, add 4. 07 C /100m in Shannan depression. During Jurassic, the former washigher than the later, but could not be higher than 3 oC /100m, and it was lower in Luxi bulge.The present geothermal gradient is higher in west than in east, and its variation is uneven withdepth. The feature could be relation with paleogeotemperature and lithology. Stratigraphic compensation thickness, which is calculated on the basis of theory of the temperature insufficientcompensation, is not all equal to the erosion thickness. By analysis, the eroded thickenss at theend of Triassic was about equal to the compensation thickness, and is more than 1000m.