湘中涟源凹陷镜质体反射率与地层剥蚀厚度恢复

Vitrinite Reflectance and Resume of the Strata Degradation Thickness in Lianyuan Depression in the Middle of Hunan Province

为了计算涟源凹陷的剥蚀量,恢复其构造演化,采用了涟源凹陷各地层平均镜质体反射率和刘家塘组的Ro值分析了涟源凹陷的平面展布。结果表明,涟源凹陷在中晚泥盆世的沉降速度最快;晚泥盆世-石炭纪沉降速度相对减慢;在二叠纪-三叠纪沉降速度进一步减慢;在早三叠世晚期涟源凹陷发生了大面积的抬升,并伴随有东南-西北向的强烈挤压,出现角度不整合;晚三叠世时地层重新开始沉积。区内地层是不均匀抬升,凹陷边缘较凹陷内部抬升量大;在凹陷内部,背斜区地层破坏极为严重。

In order to calculate denudation thickness and resume tectonic evolvement of the Lianyuan depression, the vitrinite reflectance is adopted in this article. It is showed that the settling velocity of the Lianyuan depression is the largest in Middle-Late Devonian. In Late Devonian-Carboniferous, the deposition is slow down. The settling velocity The rising velocity at the edge of the depression is larger than the inside. In the depression, the rising velocity in the anticlinal belt is larger than that in synclina belt.