TY  - JOUR
A1  - Pico, Tamara
A1  - Mitrovica, Jerry X.
A1  - Perron, J. Taylor
A1  - Ferrier, Ken L.
A1  - Braun, Jean
T1  - Influence of glacial isostatic adjustment on river evolution along the US mid-Atlantic coast
JF  - Earth & planetary science letters
N2  - 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 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.
KW  - glacial-isostatic adjustment
KW  - US east coast river geomorphology
KW  - river dynamics on glacial timescales
Y1  - 2019
U6  - https://doi.org/10.1016/j.epsl.2019.06.026
SN  - 0012-821X
SN  - 1385-013X
VL  - 522
SP  - 176
EP  - 185
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Pico, T.
A1  - Mitrovica, J. X.
A1  - Braun, Jean
A1  - Ferrier, K. L.
T1  - Glacial isostatic adjustment deflects the path of the ancestral Hudson River
JF  - Geology
N2  - Quantifying the pace of ice-sheet growth is critical to understanding ice-age climate and dynamics. Here, we show that the diversion of the Hudson River (northeastern North America) late in the last glaciation phase (ca. 30 ka), which some previous studies have speculated was due to glacial isostatic adjustment (GIA), can be used to infer the timing of the Laurentide Ice Sheet’s growth to its maximum extent. Landscapes in the vicinity of glaciated regions have likely responded to crustal deformation produced by ice-sheet growth and decay through river drainage reorganization, given that rates of uplift and subsidence are on the order of tens of meters per thousand years. We perform global, gravitationally self-consistent simulations of GIA and input the predicted crustal deformation field into a landscape evolution model. Our calculations indicate that the eastward diversion of the Hudson River at 30 ka is consistent with exceptionally rapid growth of the Laurentide Ice Sheet late in the glaciation phase, beginning at 50–35 ka.
Y1  - 2018
U6  - https://doi.org/10.1130/G40221.1
SN  - 0091-7613
SN  - 1943-2682
VL  - 46
IS  - 7
SP  - 591
EP  - 594
PB  - American Institute of Physics
CY  - Boulder
ER  -