Abrupt early Holocene (9.9-9.6 ka) ice-stream advance at the mouth of Hudson Strait, Arctic Canada

Radiocarbon-dated glacial-geologic evidence documents an abrupt advance of the northern margin of the Labrador sector of the Laurentide Ice Sheet during the last deglaciation. Ice-flow directional indicators, together with ice-marginal features found onshore and offshore, delimit an ice stream that advanced north-northeast >300 km, crossed the mouth of Hudson Strait and outer Frobisher Bay, and overran summits ~400 m above sea level on outer Hall Peninsula, southeast Baffin Island. The entire advance-retreat cycle took place in an ~300 yr ( ⁴ C) interval, 9.9-9.6 ka. At its maximum extent, the ice stream supported a calving margin >200 km long terminating in open water ~500 m deep, implying a massive iceberg release. Marine evidence for the outflow is preserved along the Labrador Sea Shelf as thick carbonate-rich glacial-marine drift but has not been recognized farther east in the North Atlantic. Either the discharge of icebergs was insufficient to produce a trans-North Atlantic, carbonate-rich (Heinrich) layer, or the icebergs tracked southward where they encountered warming sea-surface temperatures. -from Authors