Restudy on the late Permian strata in Northern Qiangtang area, Tibet.

The Late Permian strata, namely Raggyorcaka Formation, is distributed along the line from Shuanghu agency to Raggyorcaka area. The Formation comprises two parts divided by fault. The lower part is mainly composed of shale and carbonate containing fusulinids and brachiopods while the upper part is dominated by flora-bearing sandstone and mudstone. Acording to the new materials got from 1∶250 000 scale Mayigangrimap, the upper terrestrial flora-bearing deposits conformably overlie the lower marine fusulinids-bearing deposits. So, based on the analysis of paleon to logy and litho stratigraphy, the original Raggyorcaka Format ion are divided in to two parts. The lower is Raggyorcaka Formation standing for fusulinids-bearing marine deposits and the upper is Heitugou Formation (P3h), a new lithostratigraphic name represen ting flora-bearing deposits.