Northeast is low-angle slope, develop constructive potamic-lake delta, The delta from headstream to lake, extend very long, sediment complex and Microfacies multiplicity.
The observed deltas are highly two-dimensional in planform, adopting palmated structures which retain throughout their evolution a high degree of mirror symmetry.
The sedimentary facies in Heshilafu is an alluvial fan - fan delta -lake systetn, and it can be further devided into several parfacies including microfacies.
Cuspate deltaic sands micro-facies, which formed at the time of powerful wave action, the continuity of marine distributary channel is bad, and distributes in cuspate shape. 3.
The paper has summarized systematically evolutionary law in time and space on petrofacies and paleogeography of Late Paleozoic era in Northern China and distributive law of depositional systems.