Abstract:

Depositional processes are a strictly relationship between sediment supply and accommodation, which is controlled by eustatic sea level and tectonic events, however CuuLong basin is a typical continental rift one, therefore, the extentional rift events were key factors leading to a imbalance of sediment supply and accommodation. Stratigraphy of CuuLong rift basin is subdivided into phases as: the initiation rift phase (Eocene and Early Oligocene) was deposited by mainly alluvial fans, braided rivers, and insignificantly lacustrine shale. The climax rift phase (Middle Oligocene) consisted of mainly lacustrine carbonaceous shale, insignificantly lacustrine sands during flooding; the waning rift phase (Late Oligocene and Early Miocene) are mainly marginal-lacustrine, delta fans, channels, sometimes lacustrine shale.