Abstract
Cryospheric events in the Arctic Ocean have been largely studied through the imprints of ice sheets, ice shelves and icebergs in the seafloor morphology and sediment stratigraphy. Subglacial morphologies have been identified in the shallowest regions of the Arctic Ocean, up to 1200 m water depth, revealing the extent and dynamics of Arctic ice sheets during the last glacial periods. However, less attention has been given to sedimentary features imaged in the vicinity of the ice-grounded areas. Detailed interpretation of the sparse available swath bathymetry and sub-bottom profiles from the Lomonosov Ridge and the Amundsen Basin shows the occurrence of mass transport deposits (MTDs) and sediment waves in the central Arctic Ocean. The waxing and waning ice sheets and shelves in the Arctic Ocean have influenced the distribution of MTDs in the vicinity of grounding-ice areas, i.e. along the crest of Lomonosov Ridge. Due to the potential of Arctic sediments to hold gas hydrates, their destabilization should not be ruled out as trigger for sediment instability. Sediment waves formed by the interaction of internal waves that propagate along water mass interfaces with the bathymetric barrier of Lomonosov Ridge. This work describes the distribution and formation mechanisms of MTDs and sediment waves in the central Arctic Ocean in relation to grounding ice and internal waves between water masses, respectively. The distribution of these features provides new insight into past cryospheric and oceanographic conditions of the central Arctic Ocean.
Highlights
Many factors control patterns of sedimentation and influence the seafloor morphology and sediment stratigraphy of continental margins, submarine ridges and oceanic basins, from initial continental break-up and major movements of tectonic plates to sea-level oscillations (e.g. Potter and Szatmari, 2009; Lovell, 2010)
The four areas at the Lomonosov Ridge are named after prominent nearby morphological features identified on the International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0 (Jakobsson et al, 2012)
The sedimentary record of the Lomonosov Ridge and the Amundsen Basin is locally disturbed by numerous sedimentary features (Fig. 2, Fig. 5), including mass transport deposits (MTDs) and sediment waves
Summary
Many factors control patterns of sedimentation and influence the seafloor morphology and sediment stratigraphy of continental margins, submarine ridges and oceanic basins, from initial continental break-up and major movements of tectonic plates to sea-level oscillations (e.g. Potter and Szatmari, 2009; Lovell, 2010). Kristoffersen et al, 2007; Mosher et al, 2010; Geissler et al, 2011; Polyak and Jakobsson, 2011; Castro et al, 2019) These features provide additional information on the processes occurring at the Arctic seafloor in relation to the grounding ice and the oceanographic pattern. The Arctic Ocean consists of two main basins, the Amerasian and Eurasian basins They are separated by the Lomonosov Ridge, which is an 1800 km long continental fragment that rifted from the Eurasian continental margin The Lomonosov Ridge experienced several phases of subsidence (Moran et al, 2006; O'Regan et al, 2008; Sangiorgi et al, 2008) At present, it is the most prominent bathymetric high of the Arctic Ocean (Fig. 1A), constituting a double-sided passive continental margin The sedimentary record covering the Lomonosov Ridge is highly variable encompassing the past ~55 Myrs, but holding several hiatuses (Backman et al, 2006; Stevenson et al, 2015)
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