摘要
In upper Yangtze Region, laminated microcrystalline limestone, calcareous shale or ribbon limestone widely developed during the earliest stage of Early Triassic, just after the Permian-Triassic boundary (PTB) mass extinction, which represented the Sluggish oceanic circulation. As seen at the sections in Jiangyou, Guangyuan, Wangcang County, Sichuan Province and Chongqing Municipality, the storm-related sediments such as brecciform limestone, flat-pebble conglomerate calcirudyte, hummocky cross-bedding grain limestone, ripple bedding siltstone uplapped on the laminated or ribbon deposits. Erosion surfaces were usually seen between the low-energy deposits and the storm-related turbulent oceanic deposits, which indicated the unusual paleo-oceanographical and paleoclimate changes during the earliest stage of Early Triassic interval. As a main type of Early Triassic anachronistic facies which showed the turbulent oceanic conditions, brecciform limestone and flat-pebble conglomerate calcirudyte were widely seen in the northwestern part of upper Yangtze Region.