The Upper Triassic Xujiahe Formation in the Bailu district,Pengzhou,Sichuan

The middle and upper members of the Xujiahe Formation have a thickness of more than 1274 m in the Bailu district,Pengzhou,Sichuan.The basal strata are geared to the coral part of the Bailu Bridge anticline,and the uppermost strata overlain with disconformi-ty by the Qianfoya Formation.The strata in the Xujiahe Formation may be ascribed,ac-cording to rock associations and geomorphological features,to the second,third and fourth members,where the coal-bearing strata of the Upper Triassic Xujiahe Formation crop.out over a wide area.The present paper deals with the distribution of the Xujiahe Formation in this region and adjacent areas,rock associations and horizontal variations,with the empha-sis on the well-developed Dongzigou section,thus improving our knowledge of the stratigraphic sequences,sedimentary environments and coal-bearing horizons in the Xujiahe Formation.