在海底以下40m深度范围内，地层岩性从上至下分别为淤泥质粘土层、硬粘土

40m below the sea floor in the depth, lithology top to bottom respectively silty clay, hard clay, sandy gravel layer, and sandy clay layer, wherein the clay silt layer formation time Holocene transgression, geotechnical layer are formed under the late Pleistocene, in early.

In the depth of 40m below the sea floor, the formation rock from top to bottom are silt clay layer, hard clay layer, gravel-bearing sand layer, clay layer and sand layer, of which, silt clay layer formation era for the new world sea invasion period, the sub-rock soil layer formed in the late, medium and early period respectively.

In the depth range of 40m below the sea floor, the lithology of the stratum is from top to bottom, which are respectively muddy clay layer, hard clay layer, gravelly sandy layer, clay layer and sandy layer. Among them, the formation age of muddy clay layer is Holocene transgression, and the formation age of lower rock and soil layer is late, middle and early Pleistocene.<br>