The Pennsylvanian–Permian transition in the low-latitude carbonate record and the onset of major Gondwanan glaciation

Abstract

Recent studies suggest a marked expansion of glacial ice across much of Gondwana beginning in the earliest Permian. Because expansion of glacial ice results in a lowering of sea level, the imprint of ice expansion should be evident worldwide as significant exposure event, hiatuses, or other evidence for sea level drop at or near the Pennsylvanian-Permian boundary. This literature review investigates the signature of an Early Permian expansion of Gondwanan ice through examination of stratigraphic records from eight carbonate-dominated, palaeotropical regions across Pangaea. Tropical carbonate environments are used because most form in tectonically quiescent regions and are sensitive indicators of eustatic change. Correlation between stratigraphic sections is achieved using the most current biostratigraphic and absolute time constraints available. All studied sections show a sequence boundary or basinward shift in facies at or near the Pennsylvanian-Permian boundary, supporting the hypothesis of a significant expansion of glacial ice and global eustatic lowstand beginning in the Early Permian. By contrast, a series of mid-Sakmarian-Kungurian transgression events in the palaeotropics are interpreted to reflect the asynchronous deglaciation of Gondwana. The stratigraphic framework developed herein will allow for better correlations among stratigraphic records from Gondwana and northern Pangaea, which will ultimately improve the understanding of how carbonate systems respond to global icehouse conditions, such as during the late Palaeozoic.

Late Paleozoic continental warming of a cold tropical basin and floristic change in western Pangea

“…Observations from Permo-Carboniferous tropical and subtropical carbonate platforms indicate a basinward facies shift very near the Pennsylvanian-Permian boundary that is interpreted to represent development of large-scale continental ice-building in Gondwanaland (Koch and Frank, 2011). The stratigraphic record above this supposed ice-building event is composed of cyclic marine or mixed-marine and continental strata interpreted to represent 4th or 5th order depositional cycles through the Asselian-Sakmarian (Koch and Frank, 2011).…”

“…The stratigraphic record above this supposed ice-building event is composed of cyclic marine or mixed-marine and continental strata interpreted to represent 4th or 5th order depositional cycles through the Asselian-Sakmarian (Koch and Frank, 2011). As mentioned, the age of strata in the eastern Midland basin of northcentral Texas is not known with precision.…”

“…It has been argued that this expansion should have, and did have, a major effect on sea-level (Rygel et al, 2008) and left a mark in areas such as carbonate platforms, which would be expected to be sensitive to a major change in sea level (Koch and Frank, 2011). The absence of a clear lithological indication of this change in the terrestrial Markley Formation is, perhaps, not particularly worrisome, given the large number of hiatuses, marked by paleosols, in this, as in any other largely terrestrial sections.…”

“…This was a time interval during which a major pulse of southern hemisphere ice has been proposed, possibly the largest glacial advance of the LPIA Isbell et al, 2003;Koch and Frank, 2011). During this time interval a major vegetational change occurred, from floras characteristic of "wet" habitats to those typical of seasonally dry habitats (DiMichele et al, 2006;Montañez et al, 2007;Opluštil, 2013).…”

Impact of continental motion and dynamic glaciations on low-latitude climate during the Carboniferous: The record of the Wyoming Shelf (Western United States)

“…Those intervals of global cooling and warming, fluctuating on time scales of 1 to 10 Myr, are thought to have been controlled by fluctuations in pCO 2 . Several recent studies have investigated the imprint of these dynamic changes of global climate on the low-paleolatitude record (e.g., Feldman et al, 2005;Bishop et al, 2010;Allen et al, 2011;Koch and Frank, 2011;Eros et al, 2012;Martin et al, 2012). In doing so, they noted the challenges entailed in deconvolving the effects of global climate change from those caused by the latitudinal drift of continental masses (Roscher and Schneider, 2006;.…”