The Barrington Submarine Mass-Transport Deposit, Western Scotian Slope, Canada
Published:January 01, 2011
David C. Mosher, D. Calvin Campbell, 2011. "The Barrington Submarine Mass-Transport Deposit, Western Scotian Slope, Canada", Mass-Transport Deposits in Deepwater Settings, R. Craig Shipp, Paul Weimer, Henry W. Posamentier
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A large submarine-slide deposit from the western Scotian Slope off eastern Canada was imaged on a 3D seismic reflection dataset in the Barrington exploration block. The mass-transport deposit (MTD) forms a tongue-shaped body that is 25 km long and 8 km wide, with a run-out distance from the headscarp of 41.5 km and a total volume of 12.5 km3. In profile, it consists of a chaotic seismic facies. This facies forms a highly rugose top surface morphology, suggesting that the flow consisted of an abundance of intact angular blocks. Its base reveals evidence of erosion typical of submarine MTDs, with linear downslope-trending gouges and excavation of a pit 50-m-deep. The source area and headscarp of the Barrington MTD are somewhat obscured by postdepositional erosion. Additionally, high-resolution seismic profiles show that the deposit is draped by approximately 30 m of late Pleistocene and Holocene sediment, providing an age estimate of 30 ka for the failure. Despite this drape, the modern seafloor above the MTD still has a highly rugose morphology, echoing the top surface of the deposit.
Seismic profile data show a series of stacked MTDs underlying the Barrington MTD, suggesting that mass-failure recurrence is common on geologic time scales. Although it is difficult to attribute mass-failure triggering mechanisms, high sedimentation rates due to proximal shelf glaciers and intense erosion causing oversteepening, and likely established preconditions for instability. Local seismicity, possibly a result of glacial rebound, is the most probable initiating factor.
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Mass-Transport Deposits in Deepwater Settings
Historically, submarine-mass failures or mass-transport deposits have been a focus of increasingly intense investigation by academic institutions particularly during the last decade, though they received much less attention by geoscientists in the energy industry. With recent interest in expanding petroleum exploration and production into deeper water depths globally and more widespread availability of high-quality data sets, mass-transport deposits are now recognized as a major component of most deep-water settings. This recognition has lead to the realization that many aspects of these deposits are still unknown or poorly understood. This volume contains twenty-three papers that address a number of topics critical to further understanding mass-transport deposits. These topics include general overviews of these deposits, depositional settings on the seafloor and in the near-subsurface interval, geohazard concerns, descriptive outcrops, integrated outcrop and seismic data/seismic forward modeling, petroleum reservoirs, and case studies on several associated topics. This volume will appeal to a broad cross section of geoscientists and geotechnical engineers, who are interested in this rapidly expanding field. The selection of papers in this volume reflects a growing trend towards a more diverse blend of disciplines and topics, covered in the study of mass-transport deposits.