Depositional Model of Gravity Flow of Slope in Large Down Warped Lake Basins

Key words: 
• down warped lake basins

Abstract: Slope break belt is the most favorable setting for gravity flow development. Slope break belt can be developed in Lake basins and has the similar characteristics with one in continental slopes. Therefore, the study on depositional model and distribution regularity of gravity flow of slope breaks in large down warped lake basins is of important significance. The characteristic of slope break belt in LonghupaoDa'an terrace of Songliao Basin is distinctive, and it is a twolevel slope break. Sublacustrine fan is formed by sediment that carried by gravity flow. The sublacustrine fan of the south Songliao basin consists chiefly of clastics carried by landslide, debrisflow and turbidity current. Taking slope break of Songliao basin as an illustration, the paper elaborated depositional models of gravity flow in short gradual slope and long gradual slope setting. This study has shown that there are distinctly different features between two type models, especially the shape and distribution pattern of sublacustrine fan and incised waterway.