Geomorphological and stratigraphic evidence along the northeastern US margin for Laurentide glacial lake outburst floods during the MIS 2 deglaciation

Citation:
Klotsko, S, Driscoll N.  2018.  Geomorphological and stratigraphic evidence along the northeastern US margin for Laurentide glacial lake outburst floods during the MIS 2 deglaciation. Quaternary Research. 90:139-152.

Date Published:

2018/07

Keywords:

Block Island Sound, catastrophic, Catastrophic draining, CHIRP seismic, drainage, england continental-shelf, event, geology, Glacial geomorphology, Glacial lake outburst floods, Glaciated margin, long-island, morphology, Physical Geography, Quaternary, slope, Southern New England, valley, wisconsin, yr

Abstract:

Block Island Sound (BIS), in southern New England, was occupied by a glacial meltwater lake (Lake BIS) during the MIS 2 deglaciation. New CHIRP seismic data, swath bathymetry, and legacy seismic profiles from BIS provide important insights and constraints on the morphologic evolution of a glaciated margin from the last glacial maximum to present. Interpretation of seismic data revealed four well-defined sediment units: acoustic basement, glaciolacustrine varved sediments, a lag deposit, and Holocene sediment. The morphology and architecture of the sedimentary units suggest that Lake BIS drained quickly, followed by the catastrophic drainage of glacial Lake Connecticut through BIS (Lake Connecticut occupied present-day Long Island Sound). The draining waters carved depressions similar to 100 m deep in the floor of BIS and the region between the lakes. The waters also carved Block Island Valley, which extends across the continental shelf. Continued existence of the depressions and valley suggests a rapid transgression over these water depths and limited sediment supply. Our results show the significant impact of glacial lake outburst floods, even during a sea level transgression, and may help explain morphology observed along other glaciated margins.

Notes:

n/a

Website

DOI:

10.1017/qua.2018.32