Integrated stratigraphic correlation of the Jixi Group and Longzhaogou Group in eastern Heilongjiang

Abstract：Chronostratigraphic division of the Jixi and Longzhaogou Groups has been made using the latest paleontological and magnetostratigraphic data and the ages of these two groups have been determined to be the Early Cretaceous Valaginian-middle Albian. Many methods such as the sequence stratigraphic approach, basin dynamic approach, event stratigraphic approach and correlation of the lake- (sea-) level fluctuation curve of basins and global sea-level fluctuation curves were used to make an integrated correlation of the two groups. It is confirmed that the two groups have an isochronous and heteropic relationship in the background of the same tectonic-subsidence cycle. The Longzhaogou Group may be divided in ascending order into four formations: the Peide Formation, Qihulin River Formation, Xiayunshan Formation and Chaoyang Formation, which laterally correspond with the Didao Formation, Chengzi River Formation, Muling Formation and Dongshan Formation of the Jixi Group respectively. The results of this study have great guiding significance for the further discussion of the Mesozoic land and sea change mechanism, establishment of the stratigraphic and tectonic frameworks and coal deposit prediction in eastern Heilongjiang.