The transitional zone in central-south Sichuan is a part of central Sichuan uplift.According to the exploration of a seismic section in this region

there had been tectonic movements between the Lower Cambrian and Middle-Upper Cambrian

the Middle-Upper Cambrian and Lower Ordovician

the Middle-Upper Ordovicion and the Wufeng Formation of the Upper Ordo-vician and the Silurian System as well

with obvious truncation and over-laps.Paleo-uplifts have three patterns in the present region:1.Gradual chang-ing pattern

represented by Caledonian paleo-uplift;2.Sudden changing pattern

represented by Luzhou paleo-uplift of the Indo-Chinese Epoch;3.Over laped uplift pattern resulted by Caledonian and Indo-China Movements.The stratigraphic thickness of Caledonian paleo-uplift differs from thatof Indo-Chinese ones in reverse.The land form during the Caledonian de-posit was high in the west and low in the east

but was reversed during the Variscian-Indo Chinese Epoch.The erosion surfaces of the Caledonian paleo-uplift in the north part of the region and that of the Indo-chinese paleo-uplift in the south may pro-bably form oil and gas pools of weathering crack

monadnock and karst types.