The physiography of High Arctic cross-shelf troughs

Post-glacial flooding of the Bering Land Bridge dated to 11 cal ka BP based on new geophysical and sediment records

“…The geological process behind the erosional unconformity marked by R1 most likely played a critical role in shaping the general morphology of Herald Canyon. While this unconformity appears similar to several ice-eroded surfaces mapped on the continental shelves, ridges and plateaus of the Arctic Ocean (Jakobsson et al, 2014), Herald Canyon is a much smaller and less pronounced physiographic feature than the smallest Arctic cross-shelf troughs formed by ice streams (Batchelor and Dowdeswell, 2014). However, with the relatively sparse geophysical mapping data it is not possible to completely rule out the possibility that glacial ice played some part in shaping the base of Herald Canyon.…”

“…Below the major change at around 407 cm, we assume that there is no connection to the Pacific Ocean and thus no inflow of relatively old Pacific waters. For this lower section, R = 50 ± 100 years is applied based on present values in the Laptev Sea (Bauch et al, 2001), the closest site with modern information on the reservoir age from a shallow, coastal Arctic shelf setting with no Pacific influence (Reimer and Reimer, 2001). In the upper 400 cm of core 4-PC1, representing the late Holocene, a larger reservoir is expected due to the Pacific influence and R = 300 ± 200 years is applied to the radiocarbon dates in this section.…”

On the reconstruction of palaeo-ice sheets: Recent advances and future challenges

“…Batchelor and Dowdeswell, 2014). Swath bathymetry data from within these troughs ( Figure 6) commonly reveals geomorphology which fulfils the criteria for palaeo-ice streams, similar to those described in terrestrial settings (Anderson et al, 2002;Ottesen et al, 13 2005Ottesen et al, 13 , 2008Livingstone et al, 2012a).…”

“…Imagery from continental slopes has revealed sedimentary depocentres (trough mouth fans : Vorren and Laberg, 1997;Batchelor and Dowdeswell, 2014), the architecture of which often indicates rapid, episodic sedimentation by ice streams (Dowdeswell et al, 1996;Dowdeswell and Elverhoi, 2002;Nygård et al, 2007). Indeed, dating of sediment packages is an important constraint on ice stream activity that is not easily available from terrestrial records, and some marine records extend back through several glacial cycles (Nygård et al, 2007).…”

PAST Gateways (Palaeo-Arctic Spatial and Temporal Gateways): Introduction and overview

“…Trough mouth fans are prominent features related to ice sheet growth and glacigenic sediment delivery along glaciated continental margins (Batchelor and Dowdeswell, 2014). Using seismic reflection data and seabed bathymetry supplemented by stratigraphical information from exploration wells, Hofmann et al investigate the long-term evolution of the Disko Bay Trough Mouth Fan on the west Greenland margin.…”