TY - JOUR
T1 - Constraints on mantle viscosity and Laurentide ice sheet evolution from pluvial paleolake shorelines in the western United States
AU - Austermann, J.
AU - Chen, C. Y.
AU - Lau, H. C.P.
AU - Maloof, A. C.
AU - Latychev, K.
N1 - Funding Information:
CYC acknowledges support from a National Science Foundation Graduate Research Fellowship. CYC and ACM would like to thank Jeroen Tromp, Hom Nath Gharti, and Aaron Putnam for their role in conceiving and developing an earlier version of this project carried out for CYC's undergraduate senior thesis in 2012–2013. CYC would also like to thank Ken Adams, Bruce Bills, and Jack Oviatt for their generous and helpful discussions during the Lake Bonneville Geologic Conference in October 2018. JA would like to thank Evan Gowan for input on the ice sheet models and the Vetlesen Foundation for support. HL acknowledges support from the Harvard Society of Fellows . We thank the anonymous reviewer for their contribution to the peer review of this work. We acknowledge computing resources from Columbia University's Shared Research Computing Facility project, which is supported by NIH Research Facility Improvement Grant 1G20RR030893-01 , and associated funds from the New York State Empire State Development, Division of Science Technology and Innovation ( NYSTAR ) Contract C090171 , both awarded April 15, 2010. Appendix A
Funding Information:
CYC acknowledges support from a National Science Foundation Graduate Research Fellowship. CYC and ACM would like to thank Jeroen Tromp, Hom Nath Gharti, and Aaron Putnam for their role in conceiving and developing an earlier version of this project carried out for CYC's undergraduate senior thesis in 2012?2013. CYC would also like to thank Ken Adams, Bruce Bills, and Jack Oviatt for their generous and helpful discussions during the Lake Bonneville Geologic Conference in October 2018. JA would like to thank Evan Gowan for input on the ice sheet models and the Vetlesen Foundation for support. HL acknowledges support from the Harvard Society of Fellows. We thank the anonymous reviewer for their contribution to the peer review of this work. We acknowledge computing resources from Columbia University's Shared Research Computing Facility project, which is supported by NIH Research Facility Improvement Grant 1G20RR030893-01, and associated funds from the New York State Empire State Development, Division of Science Technology and Innovation (NYSTAR) Contract C090171, both awarded April 15, 2010.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2020/2/15
Y1 - 2020/2/15
N2 - The deformation pattern of the paleoshorelines of extinct Lake Bonneville were among the first features to indicate that Earth's interior responds viscoelastically to changes in surface loads (Gilbert, 1885). Here we revisit and extend this classic study of isostatic rebound with updated lake chronologies for Lake Bonneville and Lake Lahontan as well as revised elevation datasets of shoreline features. The first order domal pattern in the shoreline elevations can be explained by rebound associated with the removal of the lake load. We employ an iterative scheme to calculate the viscoelastic lake rebound, which accounts for the deformation of the solid Earth and gravity field, to calculate a lake load that is consistent with the load-deformed paleotopography. We find that the domal deformation requires a regional Earth structure that exhibits a thin elastic thickness of the lithosphere (15–25 km) and low sublithospheric Maxwell viscosity (∼1019 Pa s). After correcting for rebound due to the lake load, shoreline feature elevations reveal a statistically significant northward dipping trend. We attribute this trend to continent-scale deformation caused by the ice peripheral bulge of the Laurentide ice sheet, and take advantage of the position of these lakes on the distal flank of the peripheral bulge to provide new insights on mantle viscosity and Laurentide ice sheet reconstructions. We perform ice loading calculations to quantify the deformation of the solid Earth, gravity field, and rotation axis that is caused by the growth and demise of the Laurentide ice sheet. We test three different ice reconstructions paired with a suite of viscosity profiles and confirm that the revealed trend can be explained by deformation associated with the Laurentide ice sheet when low viscosities below the asthenosphere are adopted. We obtain best fits to shoreline data using ice models that do not have the majority of ice in the eastern sectors of the Laurentide ice sheet, with the caveat that this result can be affected by lateral variations in viscosity. We show that pluvial lakes in the western United States can place valuable constraints on the Laurentide ice sheet, the shape of its peripheral bulge, and the underlying mantle viscosity.
AB - The deformation pattern of the paleoshorelines of extinct Lake Bonneville were among the first features to indicate that Earth's interior responds viscoelastically to changes in surface loads (Gilbert, 1885). Here we revisit and extend this classic study of isostatic rebound with updated lake chronologies for Lake Bonneville and Lake Lahontan as well as revised elevation datasets of shoreline features. The first order domal pattern in the shoreline elevations can be explained by rebound associated with the removal of the lake load. We employ an iterative scheme to calculate the viscoelastic lake rebound, which accounts for the deformation of the solid Earth and gravity field, to calculate a lake load that is consistent with the load-deformed paleotopography. We find that the domal deformation requires a regional Earth structure that exhibits a thin elastic thickness of the lithosphere (15–25 km) and low sublithospheric Maxwell viscosity (∼1019 Pa s). After correcting for rebound due to the lake load, shoreline feature elevations reveal a statistically significant northward dipping trend. We attribute this trend to continent-scale deformation caused by the ice peripheral bulge of the Laurentide ice sheet, and take advantage of the position of these lakes on the distal flank of the peripheral bulge to provide new insights on mantle viscosity and Laurentide ice sheet reconstructions. We perform ice loading calculations to quantify the deformation of the solid Earth, gravity field, and rotation axis that is caused by the growth and demise of the Laurentide ice sheet. We test three different ice reconstructions paired with a suite of viscosity profiles and confirm that the revealed trend can be explained by deformation associated with the Laurentide ice sheet when low viscosities below the asthenosphere are adopted. We obtain best fits to shoreline data using ice models that do not have the majority of ice in the eastern sectors of the Laurentide ice sheet, with the caveat that this result can be affected by lateral variations in viscosity. We show that pluvial lakes in the western United States can place valuable constraints on the Laurentide ice sheet, the shape of its peripheral bulge, and the underlying mantle viscosity.
KW - Lake Bonneville
KW - Lake Lahontan
KW - Laurentide ice sheet
KW - glacial isostatic adjustment
KW - mantle viscosity
KW - paleoshorelines
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U2 - 10.1016/j.epsl.2019.116006
DO - 10.1016/j.epsl.2019.116006
M3 - Article
AN - SCOPUS:85076774430
SN - 0012-821X
VL - 532
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
M1 - 116006
ER -