Geomorphological and stratigraphic evidence along the northeastern U.S. margin for Laurentide glacial lake outburst floods during the MIS 2 deglaciation
| Autor: | Neal Driscoll, Shannon A. Klotsko |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010506 paleontology
geography Varve geography.geographical_feature_category Continental shelf Last Glacial Maximum 010502 geochemistry & geophysics 01 natural sciences Paleontology Arts and Humanities (miscellaneous) Deglaciation General Earth and Planetary Sciences Glacial period Meltwater Glacial lake Geology 0105 earth and related environmental sciences Earth-Surface Processes Marine transgression |
| Zdroj: | Quaternary Research. 90:139-152 |
| ISSN: | 1096-0287 0033-5894 |
| Popis: | 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 ~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. |
| Databáze: | OpenAIRE |
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