Ro反演的盆地热史恢复方法与相关问题

同一盆地不同深度的镜质体反射率 (Ro)是盆地所受热流密度变化的反映。因此 ,可通过建立盆地的古热流、古地温及镜质体反射率模型来反映盆地演化历史。但是 ,Ro 在多旋回盆地中存在多解性及不可逆性。所以 ,在用Ro 进行盆地反演时 ,应从原始盆地恢复入手 ,最大限度地挖掘可靠的Ro 资料 ;为了克服Ro 的不可逆性及可掩盖性 ,可将lgRo H剖面进行分段综合解释 ,对于被不整合分隔的沉积层 ,分段求取平均Ro 值作为该段的Ro 值 ,对于突变的lgRo H曲线 ,则应注意局部火山活动的影响 ,剔除异常值 ;另外 ,盆缘露头及浅埋区的Ro资料则主要用于说明盆地演化早期的古地温场特征

Ro INVERSION OF THERMAL HISTORY RECONSTRUCTION IN SEDIMENTARY BASIN AND ITS RELATED PROBLEMS

Vitrinite reflectance , also abbreviated to R o, in various depth of same sedimentary basin is a reflector of thermal current density changes experienced by the basin. Therefore, the evolutional history of a basin can be reflected by reconstructing ancient thermal current, paleo-ground temperature and a R o model in the basin. However, R o can be explained in several ways for multi-cycle basins and with inconvertibility, the reconstruction of a prototype basin would be started at the first and try your best to get as much reliable information about R o as possible when you conduct basin inversion with R o. In order to overcome inconvertible and coverable feature of R o, LgR o-H section can be explained segment by segment to gain average value of R o as that segment R o value in terms of the sedimentary stratum separated by unconformity. As for abrupt change LgR o-H curve, attention should be paid to effects of local volcanic activities and abnormal value should be picked out. Moreover R o. Information about basin outcrops and shallow buried areas is mainly applied to explain features of paleo-ground temperature in the early stage of the basin evolution.