See more from this Division: Topical Sessions
See more from this Session: Recent Advances in Deepwater Sedimentology: Science Driven by the Search for Natural Resources
Abstract:
The canyons are modified by both syn-depositional faulting and/or canyon wall slumping. Large (e.g., ~ 400 m vertical, 5 km lateral) canyon margin bounding faults exaggerate the canyon topography and cause the canyons to aggrade rather than migrate. The outcome is a remarkable 700 m of aggradation during the Neogene, with less than 500 m of lateral migration of the canyon axis. The high aggradation/migration ratio (i.e., greater than 1) might concentrate sandstone in significant packages of stacked pay; however, the extensive faulting could complicate reservoir continuity.
Upslope and across-slope knickpoint migration is a first order control on sediment input into the canyons. In at least two cases, canyon piracy (sediment capture or theft' from one canyon into another due to the latter having a knickpoint further upslope) causes abandonment of a canyon that was active for more than 10 Ma. The consequent development of a new canyon is relatively rapid and marked by multiple straight, parallel gullies that merge into a low-sinuosity master canyon. Understanding the complicated evolution of & interaction between canyons as well as their subsequent abandonment is important for both sand (reservoir) prediction and analysis of compartmentalization due to syn-depositional and tectonic modification.
See more from this Division: Topical Sessions
See more from this Session: Recent Advances in Deepwater Sedimentology: Science Driven by the Search for Natural Resources