Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation

The late Paleozoic ice age (LPIA) consists of multiple glaciations that waxed and waned across Gondwana during the Carboniferous and Permian. Three key intervals are evaluated using the concept of the equilibrium-line altitude (ELA) as a control on glaciation to provide insight into two intervals of...

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Autores principales: Isbell, J.L., Henry, L.C., Gulbranson, E.L., Limarino, C.O., Fraiser, M.L., Koch, Z.J., Ciccioli, P.L., Dineen, A.A.
Formato: JOUR
Materias:
Carboniferous
Equilibrium line altitude
Gondwana glaciation
Late Paleozoic ice age
Paleoclimate
Permian
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_1342937X_v22_n1_p1_Isbell
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_1342937X_v22_n1_p1_Isbell2023-10-03T16:09:35Z Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation Isbell, J.L. Henry, L.C. Gulbranson, E.L. Limarino, C.O. Fraiser, M.L. Koch, Z.J. Ciccioli, P.L. Dineen, A.A. Carboniferous Equilibrium line altitude Gondwana glaciation Late Paleozoic ice age Paleoclimate Permian The late Paleozoic ice age (LPIA) consists of multiple glaciations that waxed and waned across Gondwana during the Carboniferous and Permian. Three key intervals are evaluated using the concept of the equilibrium-line altitude (ELA) as a control on glaciation to provide insight into two intervals of paradoxical ice distribution during and following glaciation. The LPIA began in the mid-latitudes during the Viséan in western Argentina with the growth of glaciers in the Protoprecordillera. Glaciation was initiated by uplift of the range above the ELA. In the Bashkirian, deglaciation occurred there while glaciation was beginning at the same latitude in uplands associated with the Paraná Basin in Brazil. Analysis suggests that deglaciation of the Protoprecordillera occurred due to extensional collapse of the range below the ELA during a westward shift in the location of plate subduction. During Late Pennsylvanian-Early Permian peak glaciation for the LPIA, extensive glacimarine deposits indicate that glaciers reached sea level, which corresponds to a major lowering of the ELA due to global cooling. Finally, during the Early to early Late transition out of the LPIA, polar Gondwana was unglaciated. However, three glacial intervals occurred at mid- to high-latitudes in eastern Australia from the Sakmarian to the Capitanian/earliest Wuchiapingian. The magnitude of global cooling during these events is debatable as evidence indicates ice-free conditions and an elevated ELA at the South Pole in Antarctica. This suggests that severe global cooling was not the cause of the final three Australian glaciations, but rather that ELA-related conditions specific to eastern Australia drove these late-phase events. Possible causes for the Australian glaciations include: 1) anomalous cold conditions produced by coastal upwelling, 2) the presence of uplands allowing nucleation of glaciers, 3) fluctuations in pCO 2 levels, and 4) increased precipitation due to the location of the area in the subpolar low pressure belt. © 2011 International Association for Gondwana Research. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_1342937X_v22_n1_p1_Isbell
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Carboniferous
Equilibrium line altitude
Gondwana glaciation
Late Paleozoic ice age
Paleoclimate
Permian
spellingShingle Carboniferous
Equilibrium line altitude
Gondwana glaciation
Late Paleozoic ice age
Paleoclimate
Permian
Isbell, J.L.
Henry, L.C.
Gulbranson, E.L.
Limarino, C.O.
Fraiser, M.L.
Koch, Z.J.
Ciccioli, P.L.
Dineen, A.A.
Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation
topic_facet Carboniferous
Equilibrium line altitude
Gondwana glaciation
Late Paleozoic ice age
Paleoclimate
Permian
description The late Paleozoic ice age (LPIA) consists of multiple glaciations that waxed and waned across Gondwana during the Carboniferous and Permian. Three key intervals are evaluated using the concept of the equilibrium-line altitude (ELA) as a control on glaciation to provide insight into two intervals of paradoxical ice distribution during and following glaciation. The LPIA began in the mid-latitudes during the Viséan in western Argentina with the growth of glaciers in the Protoprecordillera. Glaciation was initiated by uplift of the range above the ELA. In the Bashkirian, deglaciation occurred there while glaciation was beginning at the same latitude in uplands associated with the Paraná Basin in Brazil. Analysis suggests that deglaciation of the Protoprecordillera occurred due to extensional collapse of the range below the ELA during a westward shift in the location of plate subduction. During Late Pennsylvanian-Early Permian peak glaciation for the LPIA, extensive glacimarine deposits indicate that glaciers reached sea level, which corresponds to a major lowering of the ELA due to global cooling. Finally, during the Early to early Late transition out of the LPIA, polar Gondwana was unglaciated. However, three glacial intervals occurred at mid- to high-latitudes in eastern Australia from the Sakmarian to the Capitanian/earliest Wuchiapingian. The magnitude of global cooling during these events is debatable as evidence indicates ice-free conditions and an elevated ELA at the South Pole in Antarctica. This suggests that severe global cooling was not the cause of the final three Australian glaciations, but rather that ELA-related conditions specific to eastern Australia drove these late-phase events. Possible causes for the Australian glaciations include: 1) anomalous cold conditions produced by coastal upwelling, 2) the presence of uplands allowing nucleation of glaciers, 3) fluctuations in pCO 2 levels, and 4) increased precipitation due to the location of the area in the subpolar low pressure belt. © 2011 International Association for Gondwana Research.
format JOUR
author Isbell, J.L.
Henry, L.C.
Gulbranson, E.L.
Limarino, C.O.
Fraiser, M.L.
Koch, Z.J.
Ciccioli, P.L.
Dineen, A.A.
author_facet Isbell, J.L.
Henry, L.C.
Gulbranson, E.L.
Limarino, C.O.
Fraiser, M.L.
Koch, Z.J.
Ciccioli, P.L.
Dineen, A.A.
author_sort Isbell, J.L.
title Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation
title_short Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation
title_full Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation
title_fullStr Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation
title_full_unstemmed Glacial paradoxes during the late Paleozoic ice age: Evaluating the equilibrium line altitude as a control on glaciation
title_sort glacial paradoxes during the late paleozoic ice age: evaluating the equilibrium line altitude as a control on glaciation
url http://hdl.handle.net/20.500.12110/paper_1342937X_v22_n1_p1_Isbell
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