Ӧ�ø߷ֱ��ʲ���ز�ѧ�����ѧ������ۣ��ۺ�������о���⾮���ϣ����������ӵ���PI �鱡�������ǰ������ʴ�����ز㷢��ģʽ�����У�PI1��PI21 С��Ϊ�������ģʽ��PI4 С��Ϊǰ��ģʽ��PI3 ��PI4 ֮��Ϊ��ʴ����ģʽ���������ģʽ��ʾ��Դ������ȱ�����Ԫ���ý��ܣ��ɷ��Բ�; ��ԶԴ�����������������ط�����������Ԫ���ڻ��֡���ʴ����ģʽ��ʾ��Դ���ڳ�������ǿ����ʴ����ԶԴ������ʴ�̶ȼ�������ʧ��ǰ��������ʾ������������������󣬲������ࡣ3 ��ģʽ��ʾ�Ĺ�ͬ���ã�����˱�����Դ���ϲ�ԶԴ�ز������ӡ��������ࡣ�ز㷢��ģʽ��ȷ��������ȷ�����������С���Ӧ��ϵ��С���ĽӴ���ϵ��ƽ��ֲ������������ز�Աȷ����ͽ��г����ݻ������о�����ָ�����塣

Using high-resolution sequence stratigraphy and sedimentology theory��three stratigraphic developmental models ( the thin layer superimposition��progradation and erosional thinning) are established in Lasaxing area according to core and logging data�� The beds of PI1 and PI21 show the thin layer superimposition model�� PI4 shows progradation model��and the interlayer between PI3 and PI4 shows erosional thinning model�� The thin layer superimposition model shows the nearly deposition thin��close unit and poor divisibility�� The distant deposition developed thick layers��complete cycles and good divisibility�� The erosional thinning model shows the nearly deposition erosion intensively��but erosion degree weakened or disappeared with the distance growing�� The deep lake sediment thickness and number of layers increased by the progradation model�� The interaction of the three models in the strata thickness and the amount of layer increases from north to south�� The establishment of the stratigraphic models is significant for better understanding the layer's corresponding of each developmental block and layer features plane distribution��and for the study of stratigraphic correlation and sedimentary evolution��