A Carboniferous apex for the late Paleozoic icehouse

Abstract

Icehouse climate systems occur across an abbreviated portion of Earth history, comprising ∼25% of the Phanerozoic record. The Late Paleozoic Ice Age (LPIA) was the most extreme and longest lasting glaciation of the Phanerozoic and is characterized by periods of acute continental scale glaciation, separated by periods of ice minima or ice-free conditions on the order of <10 6 years. The late Paleozoic glaciogenic record of the Paraná and Kalahari basins of southern Gondwana form one of the largest, best preserved, and well calibrated records of this glaciation. In the Carboniferous, the eastern and southern margins of the Paraná Basin and the Kalahari Basin were characterized by subglacial conditions, with evidence for continental and upland glaciers. In the latest Carboniferous, these basins transitioned from subglacial reservoirs to ice-free conditions evidenced by the widespread deposition of marine deposits juxtaposed on subglacial bedforms. High-precision U-Pb zircon CA-TIMS geochronologic constraints from volcanic ash deposits in the deglacial marine black shales of the Kalahari Basin and from fluvial and coal successions, which overlie marine deposits in the Paraná, indicate subglacial evidence in these regions is constrained to the Carboniferous. The loss of ice in these regions is congruent with a late Carboniferous peak in p CO 2 and widespread marine anoxia in the late Carboniferous. The permeant retreat of glaciers in basinal settings, despite an early Permian p CO 2 nadir, highlight the influence of short-term perturbations on the longer-term CO 2 record and suggests an ice-threshold had been crossed in the latest Carboniferous. A definitive driver for greenhouse gases in the LPIA, such as abundant and sustained volcanic activity or an increased biologic pump driven by ocean fertilization, is unresolved for this period. Lastly, the proposed Carboniferous apex for the high-latitude LPIA record is incongruent with observations from the low-latitude tropics where an early Permian peak is proposed.

The Late Paleozoic Ice Age in western equatorial Pangea: Context for complex interactions among aeolian, alluvial, and shoreface sedimentary environments during the Late Pennsylvanian – early Permian

“…Soreghan et al, 2008). Moreover, Griffis et al (2022) also suggest a non-glacial origin for the silt. Overall, at this period of the Earth history, i.e.…”

“…Steele, 1987;Chan, 1989). This Late Pennsylvanian -Permian succession was deposited during the Late Paleozoic Ice Age (LPIA; Fielding et al, 2008;Montañez et al, 2016;Griffis et al, 2022) and is located in the central Pangean equatorial region (Soreghan et al, 2020). In consequence, these early Permian series provide an opportunity to study the variation of depositional environments, vegetation preservation and stratigraphic cycles considering sea-level, tectonics and sediment supply variations within glacial-interglacial phases in the equatorial Pangea.…”

The Glacial Paleolandscapes of Southern Africa: the Legacy of the Late Paleozoic Ice Age

“…Deynoux and Ghienne, 2004;Ghienne et al, 2007;le Heron and Dowdeswell, 2009; and the protracted Late Palaeozoic Ice Age, hereafter referred as LPIA (ca. 370-260 Ma, Isbell et al, 2012Montañez and Poulsen, 2013;Griffis et al, 2019aGriffis et al, , 2019bGriffis et al, , 2021Griffis et al, , 2023Montañez, 2021). Southern Africa witnesses these two glacial episodes under the form of glaciogenic sedimentary successions within the Cape and Karoo supergroups and/or relict glacial erosion features carved on the bedrock.…”