DOI: 10.1016/j.epsl.2019.116006
论文题名: Constraints on mantle viscosity and Laurentide ice sheet evolution from pluvial paleolake shorelines in the western United States
作者: Austermann J. ; Chen C.Y. ; Lau H.C.P. ; Maloof A.C. ; Latychev K.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 532 语种: 英语
中文关键词: glacial isostatic adjustment
; Lake Bonneville
; Lake Lahontan
; Laurentide ice sheet
; mantle viscosity
; paleoshorelines
英文关键词: Deformation
; Glaciers
; Iterative methods
; Lakes
; Repair
; Viscosity
; Deformation pattern
; Glacial Isostatic Adjustments
; Isostatic rebound
; Lateral variations
; Laurentide ice sheets
; Mantle viscosity
; Paleoshorelines
; Western United States
; Ice
; asthenosphere
; coastal evolution
; deformation
; glacioisostasy
; gravity field
; Laurentide Ice Sheet
; mantle source
; paleoceanography
; viscoelasticity
; viscosity
; Great Salt Lake
; United States
; Utah
英文摘要: 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. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164852
Appears in Collections: 气候变化与战略
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作者单位: Lamont Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States; Massachusetts Institute of Technology, Woods Hole Oceanographic Institution Joint Program, Cambridge, MA 02139, United States; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States; Department of Geosciences, Princeton University, Guyot Hall, Washington Road, Princeton, NJ 08544, United States; Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, United States
Recommended Citation:
Austermann J.,Chen C.Y.,Lau H.C.P.,et al. Constraints on mantle viscosity and Laurentide ice sheet evolution from pluvial paleolake shorelines in the western United States[J]. Earth and Planetary Science Letters,2020-01-01,532