【摘要】 济源凹陷是勘探的前沿地区,许多油气基础地质问题(如古地温)需要解决。由于它的中生代和第三纪具有不同性质的构造和沉积发育史,可能导致古地温和油气地质的差异性。作者通过对中生界和第三系岩心和岩屑样品的磷灰石裂变径迹测定和模拟等工作,认为济源凹陷中生代和第三纪的古地温梯度分别为2.9℃/100m和3.1℃/100m,阐明了该凹陷自中生代以来经历了两次热事件,且与该地区大地构造活动的性质变化一致,也说明磷灰石裂变径迹恢复古地温是可信的。更多还原

【Abstract】 By measuring apatite fission tracks, the paleogeotemperature gradients in the Mesozoic and Tertiary in the Jiyuan Depression, North China Basin were estimated. The annealing temperatures of the apatite fission tracks were 6774℃ and 114125℃ corresponding to the Tertiary samples and Mesozoic samples respectively. Based on the anneal modeling method, the calculated subsurface temperature gradients were 2.9℃/100m in the Mesozoic, and 3.1℃/100m in the Tertiary respectively. The different temperature gradients between the Mesozoic and Tertiary were resulted from different tectonic movements in the studied area, where a great lake depression (with lower temperature gradient) was formed in Mesozoic, and become a rift (with higher temperature gradient) in Tertiary. These temperature gradients were applied successfully in assessment of thermal evolution of organic matters of source rocks, and in estimation of generated petroleum quantity in the Jiyuan Depression. Therefore, estimation of paleogeotemperatures with apatite fission tracks is an useful tool in rebuilding basin thermal evolution, even in the basin with different tectonic natures.更多还原