Influence of glacial isostatic adjustment on river evolution along the US mid-Atlantic coast
- Long-term river evolution depends partly on crustal deformation, which shapes the topography crossed by rivers. On glacial timescales, ice-sheet growth and decay can produce crustal vertical motion of ∼10 mm/yr resulting from the solid Earth's adjustment to variations in ice and water loads, comparable to tectonically-driven rates in the most rapidly uplifting mountains on Earth. This process of glacial isostatic adjustment (GIA) can influence river courses and drainage basins substantially, particularly near former ice margins. We explore the extent to which GIA influenced the evolution of rivers along the United States east coast during the last glacial cycle. We compute gravitationally self-consistent GIA responses that incorporate recent constraints on the Laurentide Ice Sheet history through the last glacial build-up phase, and we connect the predicted variations in topography to abrupt changes in river dynamics recorded in the Hudson, Delaware, Susquehanna, and Potomac Rivers from 40 ka to present. To the extent that increasesLong-term river evolution depends partly on crustal deformation, which shapes the topography crossed by rivers. On glacial timescales, ice-sheet growth and decay can produce crustal vertical motion of ∼10 mm/yr resulting from the solid Earth's adjustment to variations in ice and water loads, comparable to tectonically-driven rates in the most rapidly uplifting mountains on Earth. This process of glacial isostatic adjustment (GIA) can influence river courses and drainage basins substantially, particularly near former ice margins. We explore the extent to which GIA influenced the evolution of rivers along the United States east coast during the last glacial cycle. We compute gravitationally self-consistent GIA responses that incorporate recent constraints on the Laurentide Ice Sheet history through the last glacial build-up phase, and we connect the predicted variations in topography to abrupt changes in river dynamics recorded in the Hudson, Delaware, Susquehanna, and Potomac Rivers from 40 ka to present. To the extent that increases in sediment transport capacity imply increases in river incision rate, the GIA-driven changes in slope and drainage area are consistent with episodes of erosion and sedimentation observed in the Hudson, Delaware, and Potomac Rivers, but inconsistent with the observed accelerated river incision in the Susquehanna River at 30-14 ka. These analyses add to a growing body of evidence showing that GIA strongly influences river evolution over millennial timescales.…
Author details: | Tamara PicoORCiD, Jerry X. MitrovicaORCiD, J. Taylor PerronORCiD, Ken L. FerrierORCiD, Jean BraunORCiDGND |
---|---|
DOI: | https://doi.org/10.1016/j.epsl.2019.06.026 |
ISSN: | 0012-821X |
ISSN: | 1385-013X |
Title of parent work (English): | Earth & planetary science letters |
Publisher: | Elsevier |
Place of publishing: | Amsterdam |
Publication type: | Article |
Language: | English |
Year of first publication: | 2019 |
Publication year: | 2019 |
Release date: | 2020/11/08 |
Tag: | US east coast river geomorphology; glacial-isostatic adjustment; river dynamics on glacial timescales |
Volume: | 522 |
Number of pages: | 10 |
First page: | 176 |
Last Page: | 185 |
Funding institution: | NSF-GRFPNational Science Foundation (NSF)NSF - Office of the Director (OD); Harvard University; NSFNational Science Foundation (NSF) [EAR-1525922]; ACS-PRF grant [58209-DNI8] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften |
Peer review: | Referiert |