Sedimentary Successions of the Early Triassic Tempestite in Southeastern Hubei Province and Their Environment Significance

The Lower Triassic in the Huangshi area,southeastern Hubei Province,is mainly marked by carbonate rocks.In this set of strata wormkalkcalclrudite belonging to storm deposit are developed.The storm sedimentary structures include erosional structures,tear-pull structures,storm-wave structures,storm eddy structure and radial fabric,quickly depositional structure after storm.The storm deposits of the Early Triassic can be grouped into 7 types of lithofacies:(A)wormkalk calclrudite with massive bedding,(B)wormkalk calclrudite with graded bedding,(C)calcarenite with hummocky or swaley cross bedding and parallel bedding,(D)calcarenite with parallel bedding,(E)calcarenite with wavy cross bedding,(F)calcisilite with horizontal bedding and(G)mudstone with homogeneous or horizontal bedding.These lithofacies constitutes 4 types of sedimentary succession:(1)storm tidal succession,(2)storm current succession in subtidal zone,(3)tempestite succession for the inner shelf and(4)storm turbidite succession for the outer shelf.Wide and abundant storm deposits may indicate that sedimentary environments from tidal flat to shelf of low latitude zone(5-20°)prevailed in southeastern Hubei Province in the Early Triassic.