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(U-Th)/He热定年技术是近年来用于沉积盆地热史研究的新技术,目前主要是利用磷灰石和锆石的He年龄来揭示地层的构造抬升和热历史.本文依据塔里木盆地钻井样品的实测磷灰石和锆石(U-Th)/He年龄数据.初步得出了该地区磷灰石(U-Th)/He年龄的封闭温度为85℃,并建立了深度/温度—年龄演化模式;锆石则未达到其较高的封闭温度.综合利用本次实测的He年龄数据结合磷灰石裂变径迹和等效镜质组反射率等古温标,模拟计算了塔里木盆地孔雀1井(KQ1)自奥陶纪末期以来的热历史.模拟结果表明,孔雀1井区奥陶纪末期的地温梯度可达35.5℃/km,志留纪—泥盆纪时期的地温梯度为33.3～34.5℃/km,白垩纪末期地温梯度27.6℃/km左右.因此,(U-Th)/He年龄结合其他古温标综合模拟的方法可以很好地揭示沉积盆地的热历史.特别是该技术为缺乏常规古温标的塔里木盆地下古生界碳酸盐岩层系所经受热史的恢复提供了新的方法.
(U-Th) / He thermal dating technology is a new technique used to study the thermal history of sedimentary basins in recent years. At present, the He ages of apatite and zircon are used to reveal the tectonic uplift and thermal history of the strata. (U-Th) / He ages of the drilling samples in the basin have been obtained.The initial closure temperature of U-Th / He age in this area is 85 ℃, and the depth / Temperature-age evolution model and zircons did not reach their higher sealing temperature.According to the measured He age data and the ancient temperature scale such as apatite fission track and the equivalent vitrinite reflectance, The thermal history of Peacock Well 1 (KQ1) in the basin since the end of Ordovician period shows that the geothermal gradient of Late Ordovician in Peacock-1 well reaches 35.5 ° C / km, that of the Silurian-Devonian period Is 33.3 ~ 34.5 ℃ / km, and the geothermal gradient at the end of Cretaceous is about 27.6 ℃ / km. Therefore, the U-Th / He age combined with other ancient temperature scale comprehensive simulation methods can well reveal the thermal history of the sedimentary basin. The technique is a Lower Paleozoic carbonate system in the Tarim Basin that lacks conventional paleo-thermal subscripts Subjected to thermal history of recovery provides a new method.