Guadalupian (geologic epoch)

Guadalupian (geologic epoch)
Name	Guadalupian
Time start	272.95
Time end	259.1
Time unit	million years ago
Era	Permian
Period	Permian
Chronology	International Commission on Stratigraphy

Contents

Guadalupian (geologic epoch) The Guadalupian is a middle interval of the Permian recognized in global chronostratigraphy and regional stratigraphy. It occupies a position between older Permian units and the later Lopingian and has been pivotal in interpretations by organizations such as the International Commission on Stratigraphy, the Geological Society of America, the United States Geological Survey, the British Geological Survey, and the Australian Stratigraphy Commission. Debates about its boundaries have involved researchers from institutions like Smithsonian Institution, University of California, Berkeley, University of Oxford, Harvard University, and Stanford University.

Definition and stratigraphic position

The epoch was formally ratified through proposals circulated among committees at the International Commission on Stratigraphy and by stratigraphers associated with the International Union of Geological Sciences, the Royal Society, the National Academy of Sciences, and the European Geosciences Union. Its base and top are defined by Global Boundary Stratotype Sections and Points endorsed by working groups comprising experts from Universidad Nacional Autónoma de México, University of Texas at Austin, Yale University, University of Tokyo, and University of Cape Town. Correlation schemes reference biozones used by paleontologists at the Natural History Museum, London, the American Museum of Natural History, the Field Museum, and the Museum für Naturkunde, Berlin.

Chronologically, the Guadalupian spans much of the middle Permian and encompasses substages that correspond to internationally recognized stages used by the International Commission on Stratigraphy, including the Roadian, Wordian, and Capitanian. These stages are divided into conodont and ammonoid biozones studied by researchers at the Geological Survey of Japan, Chinese Academy of Sciences, Russian Academy of Sciences, Instituto Geológico y Minero de España, and the Geological Survey of India. High-resolution timescales have been refined with radiometric work involving laboratories at California Institute of Technology, Max Planck Institute for Chemistry, ETH Zurich, Lamont–Doherty Earth Observatory, and the Woods Hole Oceanographic Institution.

During the Guadalupian, continental configurations reflecting the supercontinent Pangea influenced climate and sedimentation patterns recognized in basins studied by teams from Oklahoma Geological Survey, Bureau of Land Management, Geological Survey of Canada, CSIRO, and the Geological Survey of Brazil. Marine transgressions and regressions left deposits compared across the Permian Basin, the Zealandia margins, the Ural Mountains, the Karoo Basin, the Sydney Basin, the Halle–Zollern region, and the Tarim Basin. Stratigraphic records of carbonate platforms and reef systems involving taxa documented by researchers from Scripps Institution of Oceanography, University of Barcelona, ETH Zurich, and the University of Milano reveal links to events recorded by the International Ocean Discovery Program and the Ocean Drilling Program.

Faunal turnover in the Guadalupian includes diversification and decline among groups tracked by paleontologists at the Natural History Museum, London, Smithsonian Institution, Royal Ontario Museum, American Museum of Natural History, and the Chinese Academy of Sciences. Important clades such as synapsids (including taxa studied historically by Edward Drinker Cope and Othniel Charles Marsh collections), temnospondyl amphibians, brachiopods, bivalves, gastropods, ammonoids, conodonts, and reef-building organisms have been correlated across collections at the Field Museum, Museum für Naturkunde, Berlin, National Museum of Natural History, Paris, and the Royal Belgian Institute of Natural Sciences. The Capitanian extinction pulse has been linked to geochemical anomalies analyzed by groups at Max Planck Institute for Chemistry, Lamont–Doherty Earth Observatory, University of Leeds, University of Southampton, and University of California, Santa Cruz and discussed in syntheses from the Paleontological Society and the Geological Society of America.

Key stratotypes and reference sections for Guadalupian substages include carbonate sequences in the Guadalupe Mountains National Park, sections in the Ural Mountains, the Hengshan exposures, the South China Block, and the Karakum Basin, studied by personnel from the Carnegie Institution for Science, Texas Tech University, Peking University, Moscow State University, and University of Queensland. Correlations draw on magnetostratigraphy, chemostratigraphy, and biostratigraphy employed by teams affiliated with University of California, Los Angeles, Princeton University, University of Edinburgh, Seoul National University, and the University of Sao Paulo.

Guadalupian-aged strata host hydrocarbon reservoirs, evaporite deposits, and mineralization targeted by industry and agencies including ExxonMobil, Chevron Corporation, BP, Royal Dutch Shell, PetroChina, Saudi Aramco, National Iranian Oil Company, TotalEnergies, and national geological surveys such as the United States Geological Survey and the Geological Survey of India. Carbonate platform reservoirs in the Permian Basin and evaporite sequences in regions explored by ConocoPhillips, Eni, Repsol, and Petrobras have economic importance documented in reports by the International Energy Agency, World Bank, and professional societies like the Society of Petroleum Engineers.