Depositional evolution and models for a deep-lacustrine gravity flow system in a half-graben rifted sag, Beibuwan Basin, South China Sea

The Paleogene Liushagang Formation is part of the Fushan Sag, a continental lacustrine basin located at theSoutheastern margin Beibuwan Basin, South China Sea. Further understanding deep-water gravityflow deposits in this formation will be conducive to lithologic reservoir exploration sag. In study,three members Formation, SQEls3 SQEls2 and SQEls1, from old young, are used withcore observation, well log data, three-dimensional seismic data identify four deep-lacustrine gravity flowlithofacies including their vertical lateral relationships within depositional system. results thenused establish flow model. Four types lithofacies developed inthe sag: sandy debrite, turbidite, slump, bottom-current deposits. Sand-rich sub-lacustrine fan depositswith typical turbidite channels were mainly western depression, whereas distal isolated lobesformed by debrite occurred eastern depression. obtained studywill helpful research flows similar environments.