Huanghua basin is one of the Mesozoic and Cenozoic fault-limited basinsand is also one of the important oil-bearing basins in eastern China.TheEarly Tertiary sediments in it have a huge thickness of about 6000 metersresulting from two large sedimental cycles of Eocene and Oligocene eges.Itcan be divided into three stages of developments:1)The earlier

ununiform depression;2)Middle

deep depression accompanied with extension;3)The later

uplift and contraction.There are different characteristics of sedimen-tation type for each of these stages:1)Earlier stage is characterized by sedimentation predominently in environments of saline lake and alluvial fan;2)Middle stage mainly by subaqueous sedimentation from gravidational flow; 3)Later stage by extensive development of river delta.Oil and/or gas are formed and concentrated at all three above meationedstages

with the richest occurring at the middle stage.This article is dealling with the sedimentation

prccess in the Huanghua basin and its major sedimental types during the Eocene-Oligocene.