TY - JOUR
T1 - Development of Foreland Intracratonic Plateaus (Ozark Plateau and Appalachian Plateaus)
T2 - A Consequence of Topographic Inversion Due To Erosion of Adjacent Fold-Thrust Belts
AU - Anders, Alison M.
AU - Lai, Jingtao
AU - Marshak, Stephen
N1 - We thank Trish Gregg, Yan Zhan, and Brooke Dykstra for discussion of flexure and the tectonic context of the Ozark Plateau. We also benefitted from conversations with Willy Guenther, Mike DeLucia, Jeffrey Kwang, and Evan Thaler on the geology and geomorphology of the Ozarks. We are grateful to an insightful review of an early version of this paper by Lijun Liu. We thank Amanda Keen-Zebert and Mark Hudson for extremely constructive and thoughtful reviews that led us to refine and improve this work.
PY - 2022/4
Y1 - 2022/4
N2 - Unlike well-known plateaus associated with Cenozoic orogens, the Appalachian and Ozark Plateaus of the eastern United States fringe the foreland side of a long inactive and deeply eroded orogen. These foreland intracratonic plateaus (FIPs), which are underlain by sub-horizontal cratonic-platform strata and, in places, foreland-basin strata, now lie 0.5–1.2 km above sea level, notably higher than adjacent fold-thrust belts. An escarpment lies at or near the boundary between the FIPs and the fold-thrust belts. Why did the topographic inversion leading to the development of the FIPs take place? To address this question, we built a numerical model, using Landlab, to simulate how topography evolves as foreland lithosphere flexes upward when post-tectonic erosion causes unloading. In this model, flat-lying cap-rock strata (sandstone and limestone) of the foreland have greater resistance to erosion than do the deformed, tilted, cleaved, and fractured strata of the fold-thrust belt, especially where the fold-thrust belt contains argillaceous facies. We tested the model by characterizing the development of the Ozark Plateau in the foreland of the Ouachita fold-thrust belt. Results demonstrate that regional isostatic uplift due to erosion, given reasonable differences in resistance to erosion between the fold-thrust belt and the foreland, can generate the observed topographic inversion and a distinct escarpment, yielding a plateau. This model may help explain the post-Paleozoic evolution of the Catskill Mountains, the Deep Valleys Province, and the Cumberland Plateau, highlands which border the Appalachian fold-thrust belt.
AB - Unlike well-known plateaus associated with Cenozoic orogens, the Appalachian and Ozark Plateaus of the eastern United States fringe the foreland side of a long inactive and deeply eroded orogen. These foreland intracratonic plateaus (FIPs), which are underlain by sub-horizontal cratonic-platform strata and, in places, foreland-basin strata, now lie 0.5–1.2 km above sea level, notably higher than adjacent fold-thrust belts. An escarpment lies at or near the boundary between the FIPs and the fold-thrust belts. Why did the topographic inversion leading to the development of the FIPs take place? To address this question, we built a numerical model, using Landlab, to simulate how topography evolves as foreland lithosphere flexes upward when post-tectonic erosion causes unloading. In this model, flat-lying cap-rock strata (sandstone and limestone) of the foreland have greater resistance to erosion than do the deformed, tilted, cleaved, and fractured strata of the fold-thrust belt, especially where the fold-thrust belt contains argillaceous facies. We tested the model by characterizing the development of the Ozark Plateau in the foreland of the Ouachita fold-thrust belt. Results demonstrate that regional isostatic uplift due to erosion, given reasonable differences in resistance to erosion between the fold-thrust belt and the foreland, can generate the observed topographic inversion and a distinct escarpment, yielding a plateau. This model may help explain the post-Paleozoic evolution of the Catskill Mountains, the Deep Valleys Province, and the Cumberland Plateau, highlands which border the Appalachian fold-thrust belt.
KW - Ozark Plateau
KW - landscape evolution
KW - lithospheric flexure
UR - http://www.scopus.com/inward/record.url?scp=85128752969&partnerID=8YFLogxK
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U2 - 10.1029/2021TC006957
DO - 10.1029/2021TC006957
M3 - Article
AN - SCOPUS:85128752969
SN - 0278-7407
VL - 41
JO - Tectonics
JF - Tectonics
IS - 4
M1 - e2021TC006957
ER -