Figure 4
From: Factors controlling accumulation of organic carbon in a rift-lake, Oligocene Vietnam
Sedimentological columns from the ENRECA-3 core (a–c) and the north coast of Bach Long Vi Island (d). (a) The transition from FA1 to FA3. The log illustrates basinal mudstone intervals that are locally interbedded with decimeter to a meter thick, mud-dominated slurry gravity flow deposits. (b) Interval dominated by FA3. The section is characterized by sand-dominated accumulations of turbulent, transitional and laminar flow deposits, which are interbedded with basinal black mudstone intervals. (c) The FA2 interval is characterized by mud-dominated transitional plug flow facies interbedded with varve-bearing intervals. Diatomites occur recurrently and are locally bioturbated. The top of the section shows a chaotic interval with common sediment intrusions. (d) Interval of FA2 deposits characterized by mud-rich deposits of transitional flows (e.g., fluid muds—low-strength cohesive debrites) and local low-density turbidites, which are interbedded with varve-bearing intervals. Diatomites are commonly well developed. Secondary facies include high-density turbidites, debrites and slump folded beds (transitional intervals to FA3).
