Global coal gap between Permian?Triassic extinction and Middle Triassic recovery of peat-forming plants
Global coal gap between Permian–Triassic extinction and Middle Triassic recovery of peat-forming plants
Gregory J. Retallack1, John J. Veevers2 and Ric Morante2
+ Author Affiliations
1Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403-1272
2School of Earth Sciences, Macquarie University, New South Wales 2109, Australia
Abstract
Early Triassic coals are unknown, and Middle Triassic coals are rare and thin. The Early Triassic coal gap began with extinction of peat-forming plants at the end of the Permian (ca. 250 Ma), with no coal known anywhere until Middle Triassic (243 Ma). Permian levels of plant diversity and peat thickness were not recovered until Late Triassic (230 Ma). Tectonic and climatic explanations for the coal gap fail because deposits of fluctuating sea levels and sedimentary facies and paleosols commonly found in coal-bearing sequences are present also in Early Triassic rocks. Nor do we favor explanations involving evolutionary advances in the effectiveness of fungal decomposers, insects or tetrapod herbivores, which became cosmopolitan and much reduced in diversity across the Permian-Triassic boundary. Instead, we favor explanations involving extinction of peat-forming plants at the Permian-Triassic boundary, followed by a hiatus of some 10 m.y. until newly evolved peat-forming plants developed tolerance to the acidic dysaerobic conditions of wetlands. This view is compatible not only with the paleobotanical record of extinction of swamp plants, but also with indications of a terminal Permian productivity crash from δ13Corg and total organic carbon of both nonmarine and shallow marine shales.
Lethally Hot Temperatures During the Early Triassic Greenhouse
Lethally Hot Temperatures During the Early Triassic Greenhouse
Yadong Sun1,2,*, Michael M. Joachimski3, Paul B. Wignall2, Chunbo Yan1, Yanlong Chen4, Haishui Jiang1, Lina Wang1, Xulong Lai1
+ Author Affiliations
1State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, People’s Republic of China.
2School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
3GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Schlossgarten 5, 91054 Erlangen, Germany.
4Institute of Earth Sciences–Geology and Paleontology, University of Graz, Heinrichstrasse 26, A-8010 Graz, Austria.
↵*To whom correspondence should be addressed. E-mail:
eeys@leeds.ac.uk
ABSTRACT
Global warming is widely regarded to have played a contributing role in numerous past biotic crises. Here, we show that the end-Permian mass extinction coincided with a rapid temperature rise to exceptionally high values in the Early Triassic that were inimical to life in equatorial latitudes and suppressed ecosystem recovery. This was manifested in the loss of calcareous algae, the near-absence of fish in equatorial Tethys, and the dominance of small taxa of invertebrates during the thermal maxima. High temperatures drove most Early Triassic plants and animals out of equatorial terrestrial ecosystems and probably were a major cause of the end-Smithian crisis.
