Seabed morphology and shallow sedimentary structure of the Storfjorden and Kveithola trough-mouth fans (North West Barents Sea)

Abstract

This study aims to present an overview of the seafloor morphology and shallow sedimentary structure of the Storfjorden and Kveithola Trough Mouth Fans (TMFs) on the northwestern Barents Sea continental margin. Data have been compiled from two International Polar Year (IPY) cruises (SVAIS, of the BIO Hespérides and EGLACOM of the R/V OGS-Explora) that yielded 15,340 km 2 of multi-beam bathymetry and 9,500 km of subbottom seismic profiles. In this area, the continental shelf edge defines three wide and subdued sedimentary lobes forming Storfjorden TMF, one single lobe on Kveithola TMF, and three inter-TMF areas on the continental slope. The two northernmost lobes of Storfjorden TMF (Lobes I and II) are composed by thick (up to 50 m) sequences of glacially derived debris flow deposits interbedded with thin a few metres de-glacial and interglacial deposits. A network of upper slope gullies incises these debris flow deposits as a consequence of subglacial meltwater release at or near the shelf break. Gullies evolve into channels whose morphologic evidence disappears midslope, leaving place to a subdued chevron-like morphological pattern inherited by the preceeding glacial maximum debris flow deposits. A drastic change occurs on the continental slope of Storfjorden TMF Lobe III and Kveithola TMF, where are several translational submarine landslides mostly originated in the upper slope, the majority of which detach at the contact between Middle Weishelian glacigenic debris flows and the overlying acoustically laminated plumites. Dendritic canyon systems only develop in inter-TMF areas. The data suggest that TMF continental slope progradation depends on short-lived episodes of extreme sedimentation during glacial maxima and during the early deglaciation phase, and that an important controlling factor is the mechanism of ice stream retreat from the continental shelf edge. We suggest that the two northern Storfjorden sub-ice streams were composed by thicker and perhaps faster ice progressively draining a distal and larger ice source mainly located on Svalbard. Conversely, the southernmost Storfjorden sub-ice stream and the Kveithola ice stream were fed by a local, smaller marinebased ice dome grounded on Spitsbergenbanken. The ice dome persisted after the LGM, maintaining a local ice drainage system close to the shelf edge whose sedimentary evidence can be found on the continental slope of the southern lobe of Storfjorden TMF and Kveithola TMF. The high degree of lateral variability in the style of sedimentation on TMF slopes suggests that ice stream dynamics may vary considerably within the same glacial trough, and that such variability affects the long-term development of the architecture of TMFs.

Paleomagnetism and rock magnetism from sediments along a continental shelf-to-slope transect in the NW Barents Sea: Implications for geomagnetic and depositional changes during the past 15 thousand years

“…Caricchi et al Global and Planetary Change 160 (2018) [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] (LGM) (Pedrosa et al, 2011;Rebesco et al, 2011;Rüther et al, 2012;Bjarnadóttir et al, 2013). The E-W trough is relatively small with a length of 90 km from the shelf edge to the eastwards termination, and < 15 km wide.…”

Arctic and Antarctic submarine gullies—A comparison of high latitude continental margins

“…The significant differences in gully incision depth and shelf-indentation observed between some Arctic and Antarctic gullies may therefore reflect differences in the timing of initial glaciation and the number of Subbottom data from some high latitude margins (e.g., Storfjorden TMF, northern Barents Sea; Belgica Fan, Bellingshausen Sea, Antarctica) show that submarine gullies incise glacial debris flow deposits, suggesting that erosion of some gullies likely post-dates the last glacial advance to the shelf edge (Vorren et al, 1989;Laberg et al, 2007;Pedrosa et al, 2011;Ó Cofaigh, 2012). As the most recent episodes of gully erosion (since LGM) may obscure previously developed gullies, it is difficult to rule out gully formation over longer timescales without high resolution three-dimensional seismic datasets from glacial margins.…”

Late Weichselian and Holocene palaeoceanography of Storfjordrenna, southern Svalbard

“…The 254 km long Storfjordrenna, a continuation of the trough that extends towards the shelf break, is located beyond this sill. The bottom depth along the trough axis varies between 150 and 420 m (Pedrosa et al, 2011).…”