A TURBIDITY-CURRENT MODEL TO SIMULATE IMPACTOF BASIN-SCALE FORCING PARAMETERS

摘要

A numerical model was developed to simulate sedimentary architectures created by turbidity currents over geological time. The model is based on the cellular automata paradigm. The automata exchange matter and energy and are built to reproduce the physical processes which govern turbidity-current behavior. The simulated architecture is the result of a given set of geological events. For each of these events a steady state is computed. This steady state is assumed to be representative of the average effect of a turbidity current on the construction of the sedimentary architecture. Using the model, we studied the impact of external controls on deep-water depositional systems. Topographic control on geological deposits is studied using various slopes. Several architectures are also reproduced thanks to spatial and temporal variations in the frequency and magnitude of the turbidity-current events. The role of suspended-sediment concentration and grain-size distribution on the transport efficiency are presented. The model results show that small variations of flow inputs may have strong controls on deposit evolution. This numerical approach allows a better identification and understanding of key physical parameters and may provide a better prediction of reservoir architecture in deep-sea clastic systems.