Impact of climatic step-changes on source-to-sink systems: Petrographic changes across the Permian-Triassic changes on the Finnmark Platform, Barents Sea, N Norway
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<p><span><span>The emplacement of the Siberian Traps Large Igneous Province around the Permian&#8211;Triassic boundary significantly affected both climate and depositional environments across the world. Known long term consequences of this event are (I) global warming, (II) increased continental weathering, (III) oceanic stagnation and acidification and (IV) mass extinction. These effects have the potential to strongly alter signals from source-to-sink systems in terms of petrography, sediment volumes and geochemistry. The Barents Sea Basin is an excellent area to investigate the response of source-to-sink systems to such climatic changes because it contains a continuous record of sediments deposited before, during and after the Permian-Triassic event, and because this interval is sampled in several exploration wells.</span></span></p><p><span><span>The goal of this project is to investigate how the Triassic climatic changes were expressed in source-to-sink systems, mainly using techniques such as facies analysis, petrograpy, mudstone geochemistry and sediment volumes. Herein we present preliminary results mainly from sandstone petrology. On the Finnmark Plattform, the upper Permian strata of the R&#248;ye Formation contains spiculitic mudstones and limestones with sparse sandstones. These are overlain by mudstones, interbedded turbidites and prograding deltas of the Lower Triassic. In order to determine how the signal from the catchment changed to the great climatic changes, it is of high importance to examine changes within provenance and sediment volumes across the P-T boundary.</span></span></p><p><span><span>I wish to give this presentation as a poster</span></span></p>Keywords:
Sink (geography)
The mass extinction at the end of the Permian was the most profound in the history of life. Fundamental to understanding its cause is determining the tempo and duration of the extinction. Uranium/lead zircon data from Late Permian and Early Triassic rocks from south China place the Permian-Triassic boundary at 251.4 +/- 0.3 million years ago. Biostratigraphic controls from strata intercalated with ash beds below the boundary indicate that the Changhsingian pulse of the end-Permian extinction, corresponding to the disappearance of about 85 percent of marine species, lasted less than 1 million years. At Meishan, a negative excursion in delta13C at the boundary had a duration of 165,000 years or less, suggesting a catastrophic addition of light carbon.
Geochronology
Permian–Triassic extinction event
Early Triassic
Extinction (optical mineralogy)
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Biplot
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Abstract Differences in particle roundness and petrography have been studied in more than 250 gravel pits all over Gotland. The recording of petrographic properties was. however, restricted to the differences in the percentual representation of limestones, marlstone. Burgsvik sandstone, and the erratic, Precambrian elements. Gotland may be divided into distinct regions, according to the petrography of the gravels. The differences are interpreted as being due, to a certain extent, to the influence of various ice flows over the island, where the ice flows carried material of specific petrographic composition. The possibility of tracing the source formation of littoral accumulations by using petrographic analysis has been investigated. It is considered that such analyses alone are not sufficient to allow safe conclusions to be drawn.
Marl
Eemian
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Newly obtained foraminifer faunas from the Permian-Triassic (P-Tr) transition at the Dajiang and Bianyang sections in the Nanpanjiang Basin, South China, comprise 61 species in 40 genera. They belong to the Palaeofusulina sinensis Zone, the youngest Permian foraminifer zone in South China. Quantitative analysis reveals that the last occurrences of more than a half of species (28/54) fall into a 60-cm-interval at the uppermost Changhsingian skeletal packstone unit and thus calibrate the end-Permian extinction to the skeletal packstonecalcimicrobial framestone boundary. About 93% (54/58) of species of the latest Permian assemblage became extinct in the P-Tr crisis. Four major foraminiferal groups, the Miliolida, Fusulinida, Lagenida, and Textulariina, have extinction rates up to 100%, 96%, 92%, and 50%, respectively, and thus experienced selective extinctions. Both Hemigordius longus and ? Globivalvulina bulloides temporarily survived the end-Permian extinction event and extended into the earliest Triassic but became extinct soon after. The post-extinction foraminifer assemblage is characterized by the presence of both disaster taxa and Lazarus taxa. Foraminifer distribution near the P-Tr boundary also reveals that the irregular contact surface at the uppermost Permian may be created by a massive submarine dissolution event, which may be coeval with the end-Permian mass extinction. A new species, Rectostipulina hexamerata, is described here.
Permian–Triassic extinction event
Extinction (optical mineralogy)
Early Triassic
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The stratigraphical and geographical distribution of 851 brachiopod species from 216 genera and 65 families in the Permian of South China are analysed. It is revealed that the brachiopod diversity underwent two sharp falls during the Permian. The first occurred at the end of Maokouan, accompaning the widely recognised, extensive regression across the Maokouan‐Wujiapingian boundary. Fifty‐seven species of 29 genera survived this first major extinction event. The second sharp reduction of brachiopod diversity took place in the later Changhsingian, with only 17 Permian‐type brachiopod species of 12 genera straggling into the earliest Triassic. Detailed stratigraphic analysis shows that more than 90% of the Changhsingian brachiopod species disappeared at different levels in the Changhsingian before the widely perceived end‐Permian 'mass extinction' occurred. It is also notable that each of the step‐wise diversity reduction events was apparently heterochronous. In view of the evidence from lithologies, faunal components and geochemical analyses, the two sharp falls of Permian brachiopod diversity in South China are considered to be closely related to multiple interactions of an environmental deterioration caused by large‐scale regressions. Key words: PermianBrachiopodaDiversity PatternsExtinction
Permian–Triassic extinction event
Extinction (optical mineralogy)
Lithology
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Study of Indian refractory materials, under the petrographic microscope does not appear to have received sufficient attention. Petrographic data on Indian silica and magnesite bricks have been presented as also those on some foreign bricks for comparison. Correlated data like true density, thermal expansion, etc. have been included for a better appreciation of the petrographic data given.
Refractory (planetary science)
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Abstract Ammonoids suffered a diversity bottleneck during the Permian-Triassic mass extinction (PTME) and experienced a rapid diversification in the Early Triassic. However, the kinds of ammonoids that were more likely to survive the PTME and that fueled subsequent diversification are still poorly known. We compiled a comprehensive morphological data set and used the nonmetric multidimensional scaling method to reveal the impact of the PTME on the morphological selectivity of ammonoids. Our results show that postextinction taxa occupied a quite different morphospace when compared with the pre-extinction assemblages. The survivors were mainly smooth and weakly ornamented forms, while the late Permian species were dominated by coarsely ornamented forms. Contrary to previously recognized nonselective patterns, these results suggest a morphological selectivity of the Permian-Triassic crisis. Newcomers in the Griesbachian were mainly compressed and smooth forms. This morphological shift from the coarsely ornamented ammonoids dominating the Changhsingian to the smooth ammonoids dominating the Griesbachian possibly suggests an ecological turnover of ammonoids during the PTME.
Early Triassic
Extinction (optical mineralogy)
Permian–Triassic extinction event
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Permian–Triassic extinction event
Early Triassic
Extinction (optical mineralogy)
Terrestrial ecosystem
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Early Triassic
Permian–Triassic extinction event
Extinction (optical mineralogy)
Biota
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