Abstract:

Paralic lacustrine basins in eastern China generally can be divided into two kinds,i.e.,depression basins and fault-block basins.Most of the mare fault-blockbasins.The distinct feature of the former is that giant sedimental systems of deltasare well developed within the basins,and sedimental facies zones distribute circularly around the centre of a basin.The fault-block basins can also be subdivided further into circular and elongated ones.Generally speaking,sub-aqueous fans are formed near the steep side of a half graben,and deltas are usually developed along the terminal of a fault-block basin's long axes;deep water fans and turbidity sandbodies are developed in places where the water is deep.It is often the case that big-or medium-sized deltas with low content of sands are generally deposited on the gentle slope of a broad depression where the slopearea is larger and the dip is lower;whereas diluvial fans are usually developedon that of a narrow depression where the slope area is smaller and the dip issteeper;turbidities formed by subaqueous landslide or small deltas with high content of sands occur on gentle slope only on exceptional cases.