Application of the Principles of Seismic Geomorphology to Continental Slope and Base-of-Slope Systems: Case Studies from SeaFloor and Near-Sea Floor Analogues
The study of near-seafloor deepwater landscapes and the processes that form them are as important to the understanding of deeply buried marine depositional systems as the study of modern fluvial environments is to our understanding of ancient terrestrial depositional systems. In fact, these near-seafloor studies follow in the great tradition established by earlier clastic sedimentologists in the use of modern systems to understand ancient environments. The acquisition and mapping of exploration 3D seismic surveys over the last few decades allows for the study of seafloor geomorphology with a spatial resolution comparable to most deepwater multibeam bathymetric tools, and represents a significant advancement that can be used to push forward general understanding of slope and base-of-slope depositional systems through the application of the emerging science of seismic geomorphology. The papers assembled for this volume demonstrate the utility of seafloor-to-shallow subsurface data sets in studying the development of submarine landscapes and their affiliated sedimentary deposits. These contributions highlight the controls of slope morphology on patterns of both sedimentation and erosion. Many of the papers also highlight the influence of pre-existing seafloor relief on confining sediment-gravity flows specific transport pathways, thereby affecting subsequent evolution of the seafloor. The understanding of depositional processes that comes from studying deepwater analogue systems remains the best way take to knowledge from one basin or system and apply confidently to another for prediction and characterization of reservoirs for exploration and production of hydrocarbons.
Alternating Bottom-Current-Dominated and Gravity-Flow-Dominated Deposition in a Lower Slope and Rise Setting—Insights from the Seismic Geomorphology of the Western Scotian Margin, Eastern Canada
-
Published:January 01, 2012
-
CiteCitation
D. Calvin Campbell, Mark E. Deptuck, 2012. "Alternating Bottom-Current-Dominated and Gravity-Flow-Dominated Deposition in a Lower Slope and Rise Setting—Insights from the Seismic Geomorphology of the Western Scotian Margin, Eastern Canada", Application of the Principles of Seismic Geomorphology to Continental Slope and Base-of-Slope Systems: Case Studies from SeaFloor and Near-Sea Floor Analogues, Bradford E. Prather, Mark E. Deptuck, David Mohrig, Berend Van Hoorn, Russell B. Wynn
Download citation file:
- Share
Abstract
The seismic geomorphology of a succession of alternating gravity-flow-dominated and bottom-current-dominated deposits along the continental slope and rise off western Nova Scotia demonstrates the importance of inherited geomorphology on subsequent deposition patterns in mixed turbidite and contourite depositional systems. In the study area, widespread mass wasting and channel incision during the Miocene created a steep ramp with a complex geomorphology along the lower continental slope. In the Late Miocene and Pliocene, a sediment drift was constructed on the continental rise, forming a 50-km-wide terrace that onlapped the steeper slope. The location, style, and evolution of sediment waves associated with this sediment drift appear strongly linked to the morphology of the underlying surface. The orientation and extent of wave crests show strong correspondence to underlying geomorphic elements, with the most prominent sediment waves forming downcurrent of seafloor perturbations like failure escarpments and salt diapirs. The erosional and constructional morphology of the contour-current-swept seafloor in turn strongly influenced the trajectory and response of subsequent down-slope-oriented submarine sediment gravity flows later in the Pliocene. Preferential accumulation took place above a regional terrace constructed as the sediment drift evolved, promoting deposition from sediment gravity flows that may have otherwise been transported into deeper water. The positive relief of wave crests guided sediment gravity flows down the slope, with erosion and deposition focused along wave troughs. This study highlights the complex feedback that exists between along-slope and down-slope constructional and degradational processes.
- ancient ice ages
- Atlantic Ocean
- Atlantic Ocean Islands
- basins
- bedload
- Cenozoic
- continental margin
- erosion
- Europe
- geophysical methods
- geophysical surveys
- Great Britain
- ice sheets
- Neogene
- North Atlantic
- Northern Hemisphere
- ocean circulation
- paleocirculation
- Pliocene
- Scotland
- sedimentary basins
- seismic methods
- seismic stratigraphy
- Shetland Islands
- surveys
- Tertiary
- United Kingdom
- Western Europe
- Faeroe-Shetland Channel
- West Shetland Drift