@article {6869, title = {Mass Wasting on Alpha Ridge in the Arctic Ocean: New Insights from Multibeam Bathymetry and Sub-bottom Profiler Data}, volume = {500}, year = {2020}, month = {May 13}, pages = {323-340}, abstract = {

Marine geological and geophysical data from Alpha Ridge in the Arctic Ocean are sparse because of thick perennial sea-ice cover, which prevents access by most surface vessels. Rare seismic data in this area, acquired largely from drifting ice-camps, had shown the hemipelagic drape that covers most of the ridge is highly disrupted within a large (\>90 000 km2) south central region. Here, evidence of pronounced seafloor erosion and debris flows infilling seafloor lows was previously interpreted to be the result of a possible bolide impact. In recent years, several icebreaker expeditions have successfully acquired multibeam bathymetry and sub-bottom profiler data in the western segment of this region. Analysis of these data reveals a complex seafloor morphology characterized by ridges and troughs, angular blocks and escarpments as well as seismic facies characterized by hyperbolic seafloor reflections, and convoluted to incoherent and transparent sub-bottom reflectivity. These features are interpreted as evidence of sediment mass movement with varying degrees of lateral transport deformation. At least two episodes of failure are interpreted based on the presence of both buried and surficial mass-transport features. As multiple events are interpreted, seismicity is the most plausible trigger mechanism rather than bolide impact.

}, doi = {https://doi.org/10.1144/SP500-2019-196}, author = {Boggild, K. and David C Mosher and Travaglini, P.G. and Gebhardt, C. and Larry A Mayer} } @article {5949, title = {Surficial Geology Mapping of the Arctic Ocean: Using Subbottom Profiling and Multibeam Echosounding Data Sets to Constrain the Subsea North of 64{\textdegree} as a Layer for the IBCAO}, year = {2016}, month = {December 12-16}, pages = {San Francisco, CA}, abstract = {

Barriers to data collection such as perennial ice cover, climate, and remoteness have contributed to a paucity of geologic data in the Arctic. The last decade, however, has seen a multi-national push to increase the quantity and extent of data available at high latitudes. With increased availability of geophysical and geological data holdings, we expand on previous mapping initiatives by creating a comprehensive surficial geology map as a layer to the International Bathymetric Chart of the Arctic Ocean (IBCAO), providing a way to collectively analyze physiography, morphology and geology. Acoustic facies derived from subbottom profiles, combined with morphology illuminated from IBCAO and multibeam bathymetric datasets, and ground truth data compiled from cores and samples are used to map surficial geology units. We identified over 25 seismo-acoustic facies leading to interpretation of 12 distinct geologic units for the Arctic Ocean. The largest variety of seismic facies occurs on the shelves, which demonstrate the complex ice-margin history (e.g. chaotic bottom echoes with amorphous subbottom reflections that imply ice scouring processes). Shelf-crossing troughs generally lead to trough mouth fans on the continental margin with characteristic glaciogenic debris flow deposits (acoustically transparent units) comprising the bulk of the sedimentary succession. Other areas of continental slopes show a variety of facies suggesting sediment mass failure and turbidite deposition. Vast areas of the deep water portion of the Arctic are dominated by parallel reflections, indicative of hemi-pelagic and turbidity current deposition. Some deep water parts of the basin, however, show evidence of current reworking (sigmoidal reflections within bedforms), and contain deep sea channels with thalwegs (bright reflections within channels) and levee deposits (reflection pinch-out). These results delineated in the surficial geology map provide a comprehensive database of regional geologic information of the Arctic Ocean that can be applied to a variety of disciplines, including the study of Arctic sedimentary processes, climatologic and oceanographic processes, environmental and geohazard risk assessment, resource management, and Extended Continental Shelf mapping.

}, keywords = {atlantic ocean, ibcao, surficial geology mapping}, author = {Dr. Ken C Baldwin and David C Mosher and Gebhardt, C.} } @proceedings {5710, title = {Mapping the Surficial Geology of the Arctic Ocean: A Layer for the IBCAO}, year = {2015}, month = {March 23 - 25}, publisher = {Society of Petroleum Engineers}, address = {Copenhagen, Denmark}, abstract = {

The purpose of this paper is to show early results of surficial geologic mapping of the Arctic Ocean. Analysis of subbottom profiler and multibeam bathymetric data in conjunction with the regional morphology rendered from the IBCAO data are used to map nine surficial geologic units in the Arctic Ocean. For a relatively small ocean basin, the Arctic Ocean reveals a plethora of margin and basin types reflecting both the complex tectonic origins of the basin and its diverse sedimentation history. Broad and narrow shelves were subjected to a complex ice-margin history in the Quaternary, and bear the sediment types and morphological features as a result. Some shelf areas are heavily influenced by rivers. Extensive deep water ridges and plateaus are isolated from coastal input and have a long history of hemipelagic deposition. The flanks of the basins demonstrate complex sedimentation patterns resulting from mass failures and ice-margin outflow. The deep basins of the Arctic Ocean are filled with turbidites resulting from these mass-flows and are interbedded with hemiplegic deposits.

}, author = {David C Mosher and Courtney, R.C. and Martin Jakobsson and Gebhardt, C. and Larry A Mayer} } @article {5518, title = {Mapping the Surficial Geology of the Arctic Ocean}, year = {2014}, month = {Dec 15 - 19}, address = {San Francisco, CA}, abstract = {

Surficial geologic mapping of the Arctic Ocean was undertaken to provide a basis for understanding different geologic environments in this polar setting. Mapping was based on data acquired from numerous icebreaker and submarine missions to the polar region. The intent was to create a geologic layer overlying the International Bathymetric Chart of the Arctic Ocean. Analysis of subbottom profiler and multibeam bathymetric data in conjunction with sediment cores and the regional morphology rendered from the IBCAO data were used to map different surficial geologic units. For a relatively small ocean basin, the Arctic Ocean reveals a plethora of margin and basin types reflecting both the complex tectonic origins of the basin and its diverse sedimentation history. Broad and narrow shelves were subjected to a complex ice-margin history in the Quaternary, and bear the sediment types and morphological features as a result. Some shelfal areas are heavily influenced by rivers. Extensive deep water ridges and plateaus are isolated from coastal input and have a long history of hemipelagic deposition. An active spreading ridge and regions of recent volcanism have volcani-clastic and heavily altered sediments. Some regions of the Arctic Ocean are proposed to have been influenced by bolide impact. The flanks of the basins demonstrate complex sedimentation patterns resulting from mass failures and ice-margin outflow. The deep basins of the Arctic Ocean are filled with turbidites resulting from these mass-flows and are interbedded with hemiplegic deposits.\ 

}, author = {David C Mosher and Martin Jakobsson and Gebhardt, C. and Larry A Mayer} }