Global Permian tetrapod biostratigraphy and biochronology
Published:January 01, 2006
Spencer G. Lucas, 2006. "Global Permian tetrapod biostratigraphy and biochronology", Non-Marine Permian Biostratigraphy and Biochronology, Spencer G. Lucas, Giuseppe Cassinis, Joerg W. Schneider
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The most extensive Permian tetrapod (amphibian and reptile) fossil records from the western United States (New Mexico–Texas) and South Africa provide the basis for definition of 10 landvertebrate faunachrons that encompass Permian time. These are (in ascending order): the Coyotean, Seymouran, Mitchellcreekian, Redtankian, Littlecrotonian, Kapteinskraalian, Gamkan, Hoedemakeran, Steilkransian and Platbergian. These faunachrons provide a biochronological framework with which to determine and discuss the age relationships of Permian tetrapod faunas. Their correlation to the marine time scale and its numerical calibrations indicate that the Coyotean is a relatively long time interval of about 20 Ma, whereas most of the other faunachrons are much shorter, about 1–2 Ma long each. The Platbergian may also be relatively long, 14 Ma, although this is not certain. This suggests slow rates of terrestrial tetrapod faunal turnover during most of the Early Permian and late Middle to Late Permian, but more rapid rates of turnover during the latest Early and most of the Middle Permian, especially during the explosive initial diversification of therapsids.
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Non-Marine Permian Biostratigraphy and Biochronology
During the Permian, the single supercontinent Pangaea stretched from pole to pole. Early Permian glacial deposits are found in southern Gondwana. Along the sutures of Pangaea, mountain ranges towered over vast tropical lowlands. Interior areas included dry deserts where dune sands accumulated. Gypsum and halite beds document the evaporation of hot, shallow seas that formed the most extensive salt deposits in the geological record. The Permian period (251 to 299 Ma) encompasses nine ages (stages) arranged into three epochs (series). Most of the Permian marine timescale has been defined by global stratotype sections and points for the stage boundaries. This volume presents new data regarding the biostratigraphy and biochronology of the non-marine Permian and provides a basis for temporally ordering Permian geological and biotic history on land, and correlating that history to events in the marine realm.