Lacustrine turbidites in the Eocene Shahejie Formation, Dongying Sag, Bohai Bay Basin, North China Craton

Abstract

Investigations on turbidite sandstones are mostly confined to marine deep‐water systems with only limited information available on those developed in lacustrine environments. In this paper, we document the characteristics and distribution of a previously unrecognized sequence of lacustrine turbidite sandstones from the Dongying Sag in the Bohai Bay Basin, North China Craton. The Eocene Shahejie Formation in the Dongying Sag has been previously interpreted as a shallow lacustrine deposit, such as a deltaic system, with delta‐front to sag and back‐barrier environments. However, the numerous sandstone layers associated with the third member (Es3) of the Shahejie Formation define an integrated deep‐water turbidite system. Analysis of the characteristics of lithofacies, seismic facies and wire‐line logs of the sandstone layers has been undertaken, as well as investigation of the distribution characteristics and the factors governing the development of these sandstones. The results from our study show that the development of this turbidite sequence was controlled by a number of parameters including sediment supply, accommodation of the sag, palaeo‐topography, hydrodynamics, scale and formation of the delta, subsidence rate of the sedimentary basin, and tectonic activity associated with the Jiyang Movement during the Cenozoic destruction of the North China Craton. Copyright © 2013 John Wiley & Sons, Ltd.