冀北—辽西早白垩世沉积有机质特征与古气候环境演变

本文对冀北—辽西地区早白垩世沉积盆地富有机质沉积岩进行了初步有机地球化学分析研究。结果显示,冀北—辽西沉积盆沉积有机质特征在时间和空间上存在很大差异,代表白垩系早期沉积的滦平盆地大北沟组有机质丰度低,这不仅显示其所代表的沉积相带不利于有机质的聚集,也反映了当时生物不够繁盛;大店子组时期沉积相带发生了变化,有机质类型随着发生了变化,丰度有所增高,但总体上显示环境条件不利于生物的发育和繁盛。到了桥头组和义县组沉积岩有机质丰度大幅升高,表明生物界非常繁盛,古气候环境有利于有机质的大量生成和堆积,总体上反映了温湿的气候条件;但同时也存在较为频繁或交替性寒冷气候波动,具体的古气候环境状态尚需进一步深入研究。

Characteristics of Sedimentary Organic Matter and Paleoclimate and Environmental Evolution During Early Cretaceous Time in Northern Part of Hebei and Western of Liaoning Provinces

A primary study on the organic matter of the sediments from sedimentary basins located in northern Hebei and western Liaoning Provinces shows significant differences both spatially and temporally in the abundance and composition of organic matter over these sediment basins. The Dabeigou Formation which represents the earliest sediments of early Cretaous time in the Luanping Basin has a lowest organic abundance, indicating that, although the Dadianzi Formation which developed a little later shows the change in the sedimentary facies and the type of organic matter with increase in the abundance of organic matter, the paleoclimate and environment were not favorable to the development and accumulation of organic matter. By the time of the sedimentation of the Qiaotou and Yixian Formations, the abundance of organic matter was in great abundance, suggesting that the organisms were thriving and that a mild and warmer paleoclimate and environments were favorable to the organic matter Formation and accumulation. However, cold climate occurred frequently and the true reason for this need further investigation.