University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Earth and Atmospheric Sciences, Department Papers in the Earth and Atmospheric Sciences of 8-2011 The Pennsylvanian–Permian transition in the low-latitude carbonate record and the onset of major Gondwanan glaciation Jesse Koch University of Nebraska-Lincoln, [email protected] Tracy D. Frank University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/geosciencefacpub Part of the Earth Sciences Commons Koch, Jesse and Frank, Tracy D., "The Pennsylvanian–Permian transition in the low-latitude carbonate record and the onset of major Gondwanan glaciation" (2011). Papers in the Earth and Atmospheric Sciences. 300. https://digitalcommons.unl.edu/geosciencefacpub/300 This Article is brought to you for free and open access by the Earth and Atmospheric Sciences, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Papers in the Earth and Atmospheric Sciences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Published in Palaeogeography, Palaeoclimatology, Palaeoecology 308:3–4 1 (August 1, 2011), pp. 362-372; doi: 10.1016/j.palaeo.2011.05.041 Copyright © 2011 Elsevier B.V. Used by permission. Submitted October 23, 2010; revised April 24, 2011; accepted May 27, 2011; published online June 1, 2011. The Pennsylvanian–Permian transition in the low-latitude carbonate record and the onset of major Gondwanan glaciation Jesse T. Koch and Tracy D. Frank Department of Earth and Atmospheric Sciences, University of Nebraska–Lincoln, Lincoln, NE 68588, USA Corresponding author — J. T. Koch, email [email protected] Abstract Recent studies suggest a marked expansion of glacial ice across much of Gondwana beginning in the earliest Permian. Because ex- pansion of glacial ice results in a lowering of sea level, the imprint of ice expansion should be evident worldwide as significant expo- sure event, hiatuses, or other evidence for sea level drop at or near the Pennsylvanian–Permian boundary. This literature review in- vestigates 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 tec- tonically quiescent regions and are sensitive indicators of eustatic change. Correlation between stratigraphic sections is achieved us- ing 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 trans- gression events in the palaeotropics are interpreted to reflect the asynchronous deglaciation of Gondwana. The stratigraphic frame- work 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. Keywords: Pennsylvanian, Permian, carbonates, eustasy, Late Palaeozoic 1. Introduction ian Basin, Texas; 4) Arctic North America; 5) Bolivia; 6) South China Platform; 7) Russian Platform; and 8) Barents Shelf (Fig- The late Palaeozoic was a time of major climatic and envi- ure 1). These regions are analyzed in terms of lithology/cy- ronmental change that saw large-scale fluctuations in the size clicity changes across the Pennsylvanian–Permian boundary, and distribution of Gondwanan ice sheets. It has been pro- as well as the stratigraphic position of major surfaces includ- posed that the Pennsylvanian–Permian transition (hereafter ing unconformities (i.e., sequence boundaries). Results sup- PPT) is a key interval of time during the late Palaeozoic ice age port an increase in global ice volume during the earliest Perm- (LPIA) because it represents a period when ice volumes in- ian, which clarifies how low-latitude carbonate deposition creased dramatically across much of Gondwana (Isbell et al., responded to a major shift in global climate conditions. An im- 2003; Fielding et al., 2008a, 2008b, 2008c). If a significant in- proved understanding of the palaeotropics during the PPT al- crease in Gondwanan ice did occur during the earliest Perm- lows for better global stratigraphic correlations across all of ian, then sedimentary environments should have recorded the Pangaea during the LPIA. major expansion of global ice volume as a series of significant exposure events or hiatuses reflecting eustatic drawdown at or 2. Background near the Pennsylvanian–Permian boundary. Tropical carbon- ate platforms including rimmed platforms, epeiric platforms, The long-held view of the LPIA was one of a single wide- and ramps are used in this study because they are especially spread glaciation event that covered much of Gondwana sensitive indicators of eustatic change. Furthermore, these from the Middle–Late Mississippian through the Early Perm- low-latitude environments are not subject to ice-proximal in- ian (e.g., Veevers and Powell, 1987). This view, based mainly fluences such as isostatic loading from glacial ice, and they of- on information from Euramerican cyclothem deposits, sug- ten occur in tectonically quiescent areas. For these reasons, gested that glacial ice volumes reached a peak during the Late stacking patterns in tropical carbonates provide ideal proxies Pennsylvanian (Veevers and Powell, 1987; Heckel, 1994, 2008). for past eustatic events (e.g., transgressions, regressions, and However, Isbell et al. (2003) reviewed the stratigraphic data unconformities). from across Gondwana and demonstrated that the LPIA could In this paper, the stratigraphic records from eight carbon- be divided into three distinct periods of glaciation (two in the ate-dominated, palaeotropical regions are examined: 1) U.S. Carboniferous and one spanning the latest Carboniferous– Midcontinent; 2) Orogrande Basin, New Mexico; 3) Perm- Sakmarian), separated by times of non-glacial conditions. The 362 THE PENNSYLVANIAN–PERMIAN TRANSITION AND THE ONSET OF MAJOR GONDWANAN GLACIATION 363 Figure 1. Map of locations used in this study (denoted by red circles). Continental configuration based on reconstructions from Golonka and Ford (2000). claim of discrete glacial intervals separated by warmer time ell, 1999). However, the review of Gondwanan stratigraphic periods during the LPIA was further resolved by work in east- data by Isbell et al. (2003) concluded that the two pre-Perm- ern Australia (Fielding et al., 2008a), where the LPIA can be ian glacial epochs were not extensive enough to have been the divided into eight distinct glacial epochs (four in the Carbon- primary mechanism that controlled the well documented base iferous and four in the Permian), each lasting 1–8 Ma, which level changes in the Euramerican cyclothem record. are separated by non-glacial intervals of equal duration. Ad- ditionally, studies based on compilations of data from other 3. Methodology and terminology Gondwanan palaeofragments indicate that multiple ice cen- ters expanded during the Early Permian in places like east- This study utilizes published stratigraphic data from across ern Australia, Antarctica, India, southern Africa, South Amer- tropical and subtropical Pangaea. Since hundreds of papers ica, and the Middle East, which suggest an acme in the earliest have been published concerning upper Palaeozoic strati- Permian (Fielding et al., 2008b, 2008c] and references therein). graphic records, this study focused on sources that describe An Early Permian glacial expansion is also supported by stratigraphically complete records that possess a high level geochemical proxy records of ice volume, pCO2 (atmospheric of chronostratigraphic control. Specific stratigraphic informa- carbon dioxide), and temperature. Late Pennsylvanian–Early tion outlined by individual authors (e.g., palaeogeographic lo- Permian stable isotopic records from around the world are cation, lithology/facies, changes in cyclicity, and stratigraphic consistent with a drop in atmospheric pCO2 in the earliest location of unconformities) was combined with the most ro- Permian, as indicated by carbon isotope records from marine bust biostratigraphic and absolute constraints available (e.g., carbonates, soil-forming minerals, and sedimentary organic Davydov et al., 1998; Ramezani et al., 2007; Figures 2 & 3). matter (Birgenheier et al., 2010; Ekart et al., 1999; Montañez The compiled records were calibrated to the Gradstein et al. et al., 2007; see Figure 2). During the PPT, a ~ 2‰ increase in (2004) time scale to produce a global stratigraphic framework. δ18O values from low-latitude marine carbonates is consistent Stratigraphic data are plotted against the most recent recon- with a significant expansion of global ice volume (Frank et al., structions of Gondwanan glacial epochs (Fielding et al., 2008c 2008). As with oxygen isotope compositions, a ~ 1‰ to 2‰ in- and references therein), as well as other global climate change crease in δ13C values occurred during the PPT, which is consis- proxies such as oxygen and carbon stable isotopic trends (e.g., tent with a drop in pCO2 and a possible increase in ocean pro- Frank et al., 2008; Grossman