Depositional environment and coal accumulation of the Lower Cretaceous Saihantala Formation in the Baiyinhua Sag of the Erlian Basin

Abstract

The Erlian Basin is characterized by the Early Cretaceous thick coals and related coalbed methane resources. In this paper, we have analyzed lithofacies, sedimentary facies, sequence stratigraphy, and coal accumulation of the Lower Cretaceous in the Baiyinhua Sag of the Erlian Basin. The coal seams, which were developed from the littoral-shallow lacustrine and braided fluvial delta plain environments, were mainly formed in the late lowstand systems tract and late transgressive systems tract. The thickest coal was distributed in the central zone of the sag, which thinned out towards the northwest and the southeast. The thick coal seams were formed when fault basin was suitable for the large-scale development and preservation of peat in the stage of the basin contraction with uniform subsidence.