Accommodation change during bypass across a late stage fan in the shallow Auger Basin

Open Access
Author:
Bohn, Charles W
Graduate Program:
Geosciences
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Peter Flemings, Thesis Advisor
  • Dr Peter B Flemings, Thesis Advisor
Keywords:
  • deepwater
  • Auger
  • bypass
  • slope accommodation
  • Macaroni Field
  • accommodation
Abstract:
Fan 1 in the Shallow Auger Fan System records the transition from ponded deposition in the Lobe Complex to bypass at the top of the Channel Complex. The Lobe Complex, at the base of Fan 1, exhibits characteristics typical of ponded deposits: it onlaps the basin margin, exhibits a concentric isopach pattern, has a lobe geometry in amplitude extraction, and is composed of continuous seismic reflectors that have uniform thickness. The transition from ponded to bypass is recorded by increasing gradients along the four channels within the Channel Complex. The slope accommodation is filled as these channels aggrade at the sediment entry point. In the proximal reaches, the channels are characterized by thick levee deposits and minimal incision. Downdip, the levee deposit thickness decreases and incision increases. Each channel aggrades to a single fixed gradient; once this gradient is achieved, the channel avulses to an area of greater accommodation. As the slope accommodation fills, channel gradients in the proximal reaches decrease and sinuosity increases. In the distal reaches of the channel, greater incision depths may compartmentalize the underlying ponded deposits.