GI-31 ice history: global ice history spanning the last deglaciation

The GI-31 ice history is constructed based on the ICE-6G ice history (Peltier et al., 2015, doi:10.1002/2014JB011176). We construct an alternate ice model (GI-31) by modifying the deglaciation geometry of the ICE-6G model while requiring that the total ice volume (or global mean sea level) history of that model be preserved in order to satisfy far-field sea-level constraints. We delay ice loss in the CIS/western LIS region within the zone west of 110°W, preserving the ICE-6G ice distribution at 15 ka in this specific region until 13 ka. The ice distribution from 15-13 ka is modified to be consistent with the median ages reported in a large dataset (n= 818) constraining the deglaciation chronology of this region. In particular, we require that regions with minimum ages older than 13 ka must be ice-free by 13 ka in the GI-31 ice history. Peltier, W.R., Argus, D.F. and Drummond, R. (2015, doi:10.1002/2014JB011176). Available here: http://www.atmosp.physics.utoronto.ca/~peltier/data.ph

Glacial isostatic adjustment directed incision of the Channeled Scabland by Ice Age megafloods.

During the last deglaciation, dozens of glacial outburst floods-among the largest known floods on Earth-scoured the Channeled Scabland landscape of eastern Washington. Over this same period, deformation of the Earth's crust in response to the growth and decay of ice sheets changed the topography by hundreds of meters. Here, we investigated whether glacial isostatic adjustment affected routing of the Missoula floods and incision of the Channeled Scabland from an impounded, glacial Lake Columbia. We used modern topography corrected for glacial isostatic adjustment as an input to flood models that solved the depth-averaged, shallow water equations and compared the results to erosion constraints. Results showed that floods could have traversed and eroded parts of two major tracts of the Channeled Scabland-Telford-Crab Creek and Cheney-Palouse-near 18 ka, whereas glacial isostatic adjustment limited flow into the Cheney-Palouse tract at 15.5 ka. Partitioning of flow between tracts was governed by tilting of the landscape, which affected the filling and overspill of glacial Lake Columbia directly upstream of the tracts. These results highlight the impact of glacial isostatic adjustment on megaflood routing and landscape evolution

The connectivity of the Bering Strait as a tool for reconstructing past sea level and ice sheets

info:eu-repo/semantics/nonPublishe