The End-Triassic Extinction (ETE) has long remained one of the lesser known among the so-called “Big Five”. There exist several hypotheses regarding the probable cause of this extinction, which can mainly be divided into events of a decline in the rate of diversification in the late Triassic contra a sudden and significant extinction event. Primary amongst the sudden events is the one of outgassing and climate/environmental change induced by Central Atlantic Magmatic Province (CAMP) volcanism. This study aims to describe the ETE using fluvial, lacustrine, deltaic and marginal-marine microbial sedimentary structures (MS), carbonatized microbial mats (CMM) as well as wrinkle structures, microbially induced sedimentary structures (MISS) from the latest Triassic- earliest Jurassic (TJB: Triassic-Jurassic boundary interval, Rhaetian to Hettangian) of Skåne, Southern Sweden. The MISS in these sites show a high diversity of structures, indicating microbial communities with high diversity in an environment usually dominated by bioturbating invertebrates. We observed structures that include top-surface (“Elephant skin”) and subsurface (“Kinneyia”) structures, carbon-rich fossilized microbial mats, microbial sideritic concretions, sideritized microbial mats, stromatolite-like layers and oncoids. Scanning Electron Microscopy (SEM) sampling also revealed structures related to the presence of both coccoidal and filamentous cyanobacteria. Overall, the diversity in observed structures indicate a thriving microbial community, with diversified and abundant ichnofossils or body fossils of possible bioturbators only observed in the early Rhaetian and younger Mid-Late Hettangian samples of deltaic or marginal-marine affinities. The lack of metazoan communities to such an extent indicates that the local environment could have reversed to a pre-Substrate Revolution state. The occurrence of abundant and diversified microbial structures in the studied TJB section, representing a relatively short time interval, reflects anachronistic facies and development of abnormal biota. This supports the occurrence of several environmental distresses (abnormal hydrochemical and physical conditions) on the Triassic-Jurassic boundary interval, in turn lending credence to the hypothesis of an abrupt climactic event such as possibly that of CAMP volcanism. / <p>Presentation was carried out online over zoom due to the at the time ongoing COVID-19 pandemic.</p> / Resurrecting a lost world in Skåne: new light on the end-Triassic mass extinction and the origin of the dinosaur dominated ecosystem / Dinosaur grave from Skåne: microbiology, taphonomy and paleomolecules of exceptionally preserved theropod remains
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-457594 |
| Date | January 2021 |
| Creators | Nesset Mattsson, Gustav |
| Publisher | Uppsala universitet, Paleobiologi |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Examensarbete vid Institutionen för geovetenskaper, 1650-6553 ; 526 |
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