摘要
This article discusses gravitational decollement structure developing characteristics and evolution pattern of the Lower Congo basin in the West African passive continental margin. Lower Congo basin lies in passive continental margin from Early Cretaceous to present, and mainly developed gravitational decollement structure which was made up of the gravitational decollement extensional structure on upper continental slope, the gravitational decollement diapir structure on the middle and lower ones, the gravitational decollement thrust structure on lower continental slope to deep sea plain. Based on structure analysis, the advance tectonic evolution pattern on the gravitational decollement structure was established from land to sea. The pattern includes three parts: gravitational decollement extensional structure which formed firstly and lied at the high point, gravitational decollement diapir ones in the middle, gravitational decollement thrust ones at the lower part which formed finally and lied at the bottom. Since early Cretaceous, Lower Congo basin developed two stages gravitational decollement structures, the first phase (early) gravitational decollement structure was active from the Early Cretaceous Albian period to Oligocene, the second phase (late) gravitational decollement structure is active from the Miocene to now.