Descriptive Outcrop Studies
Published:January 01, 2011
Abstract: Deep-marine strata of the Windermere Supergroup, which currently are exposed in an area over 35,000 km2 in the southern Canadian Cordillera, were deposited on the passive margin of Neoproterozoic western North America. In the Isaac Formation at the Castle Creek study area, stratigraphic evidence of slope instability occurs as mass-movement (slump and slide) and cohesive-debris-flow deposits that crop out locally through the 1.5-km-thick succession. These deposits are particularly common in a mass-transport deposit (MTD) up to 110 m thick that occurs sandwiched between two major channel complexes. Interstratified within these deposits are common coarse-grained channel fills that preferentially infilled irregular topography on the seafloor. In many instances, this irregular topography was most probably related to earlier emplacement of debris-flow and slump and slide deposits. Important stratigraphic characteristics in this succession suggest that this particular MTD represents a major change in the nature of sediment supply and transport and depositional processes within the basin. These changes are interpreted to be controlled principally by changes of relative sea level, which had a first-order control on sediment supply, sediment caliber, and sediment composition to the slope and more distal basin floor.
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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.