Using ground-penetrating radar and sidescan sonar to compare lake bottom geology in New England
Abstract
Post-Laurentide Ice Sheet erosion and re-deposition has had a significant influence on the geomorphology of New England. Anthropogenic activities such as forestry, farming, and construction of infrastructure such as dams and associated lake reservoirs, has further contributed to near surface changes. Unfortunately, these surface dynamics are difficult to constrain, both in space and time. One analog that can be used to estimate erosion and deposition, lake basin sedimentation, is typically derived from lake bottom sediment core samples. Reliance on core records assumes that derived sedimentation rates are representative of the broader watershed, despite being only a single point measurement. Geophysical surveys suggest that this assumption can be highly erroneous and unrepresentative of an entire lake basin. Herein, we conducted ground-penetrating radar (GPR) and side-scan sonar (SSS) surveys of multiple lakes in Maine, New Hampshire, and Vermont which are representative of different basin types to estimate sedimentation rates since Laurentide retreat. Subsequent age constraints from cores on multiple GPR-imaged horizons could be used to refine estimates of sedimentation rate change caused by evolving physical, biological, and chemical processes that control erosion, transport, and re-deposition. This presentation will provide a summary of GPR and SSS data collection methods, assumptions and limitations, structural and surficial interpretations, and key findings from multiple lake basins in New England. Results show that GPR and SSS are efficient, cost effective, and relatively accurate tools for helping to constrain lake erosion and deposition processes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMPP44B..01N
- Keywords:
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- 4914 Continental climate records;
- PALEOCEANOGRAPHY;
- 4942 Limnology;
- PALEOCEANOGRAPHY;
- 4944 Micropaleontology;
- PALEOCEANOGRAPHY;
- 4952 Palynology;
- PALEOCEANOGRAPHY