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Korte C.,Free University of Berlin | Kozur H.W.,Rezsu u. 83
Journal of Asian Earth Sciences

The Palaeozoic-Mesozoic transition is marked by distinct perturbations in the global carbon cycle resulting in a prominent negative carbon-isotope excursion at the Permian-Triassic (P-T) boundary, well known from a plethora of marine and continental sediments. Potential causes for this negative δ13C trend (and their links to the latest Permian mass extinction) have been intensively debated in the literature. In order to draw conclusions regarding causation, a general δ13C curve was defined after consideration of all available datasets and with due reference to the biostratigraphic background. The most important features of the P-T carbon-isotope trend are the following: the 4-7‰ δ13C decline (lasting ∼500,000years) is gradual and began in the Changhsingian at the stratigraphic level of the C. bachmanni Zone. The decreasing trend is interrupted by a short-term positive event that starts at about the latest Permian low-latitude marine main extinction event horizon (=EH), indicating that the extinction itself cannot have caused the negative carbon-isotope excursion. After this short-term positive excursion, the δ13C decline continues to a first minimum at about the P-T boundary. A subsequent slight increase is followed by a second (occasionally two-peaked) minimum in the lower (and middle) I. isarcica Zone. The negative carbon-isotope excursion was most likely a consequence of a combination of different causes that may include: (1) direct and indirect effects of the Siberian Trap and contemporaneous volcanism and (2) anoxic deep waters occasionally reaching very shallow sea levels. A sudden release of isotopically light methane from oceanic sediment piles or permafrost soils as a source for the negative carbon-isotope trend is questionable at least for the time span a little below the EH and somewhat above the P-T boundary. © 2010 Elsevier Ltd. Source

Moix P.,University of Lausanne | Beccaletto L.,Bureau de Recherches Geologiques et Minieres | Masset O.,ETH Zurich | Kozur H.W.,Rezsu u. 83 | And 4 more authors.
Turkish Journal of Earth Sciences

Our paper aims to give a thorough description of the infra-ophiolitic mélanges associated with the Mersin ophiolite. We propose new regional correlations of the Mersin mélanges with other mélange-like units or similar series, located both in southern Turkey and adjacent regions. The palaeotectonic implications of the correlations are also discussed. The main results may be summarized as follows: the infra-ophiolitic mélange is subdivided into two units, the Upper Cretaceous Sorgun ophiolitic mélange and the Ladinian-Carnian Hacialani{dotless} mélange. The Mersin mélanges, together with the Antalya and Mamonia domains, are represented by a series of exotic units now found south of the main Taurus range, and are characteristic of the South-Taurides Exotic Units. These mélanges clearly show the mixed origin of the different blocks and broken formations. Some components have a Palaeotethyan origin and are characterized by Pennsylvanian and Lower to Middle Permian pelagic and slope deposits. These Palaeotethyan remnants, found exclusively in the Hacialani{dotless} mélange, were reworked as major olistostromes in the Neotethys basin during the Eo-Cimmerian orogenic event. Neotethyan elements are represented by Middle Triassic seamounts and by broken formations containing typical Neotethyan conodont faunas such as Metapolygnathus mersinensis Kozur & Moix and M. primitius s. s., both present in the latest Carnian interval, as well as the occurrence of the middle Norian Epigondolella praeslovakensis Kozur, Masset & Moix. Other elements are clearly derived from the former north Anatolian passive margin and are represented by Huǧlu-type series including the Upper Triassic syn-rift volcanic event. These sequences attributed to the Huǧlu-Pindos back-arc ocean were displaced southward during the Late Cretaceous obduction event. The Tauric elements are represented by Eo-Cimmerian flysch-like and molasse sequences intercalated in Neotethyan series. Additionally, some shallow-water blocks might be derived from the Bolkardaǧ paraautochthonous and the Taurus-Beydaglari marginal sequences. ©TÜBİTAK. Source

Kozur H.W.,Rezsu u. 83 | Wardlaw B.R.,U.S. Geological Survey

The red, ammonoid-bearing limestones at Rustaq and Wadi Wasit contain Jinogondolella aserrata, the index species for the type Wordian. It occurs with an abundant smooth Mesogondolella fauna and an advanced Waagenoceras ammonoid fauna. In the Rustaq section, two species of Mesogondolella are present in both lower and upper red, ammonoid-bearing limestoneswith M. siciliensis dominating the lower beds and M. omanensis (new species) dominating the upper beds. The same two Mesogondolella species occur in the single, ammonoid-bearing limestone unit at the Wadi Wasit section, where there are additional conodont species including M. bitteri. The faunas at Wadi Wasit section and the upper red, ammonoid-bearing limestone at the Rustaq section contain Stepanovites? festivus which is indicative of the Wordian-Capitanian boundary interval. Capitanian Jinogondolella altudaensis appears in the rocks above the ammonoid-bearing limestone at the Wadi Wasit section. Source

Kraus S.H.,Free University of Berlin | Brandner R.,University of Innsbruck | Heubeck C.,Free University of Berlin | Kozur H.W.,Rezsu u. 83 | And 3 more authors.
Fossil Record

The latest Permian mass extinction, the most severe Phanerozoic biotic crisis, is marked by dramatic changes in palaeoenvironments. These changes significantly disrupted the global carbon cycle, reflected by a prominent and well known negative carbon isotope excursion recorded in marine and continental sediments. Carbon isotope trends of bulk carbonate and bulk organic matter in marine deposits of the European Southern Alps near the low-latitude marine event horizon deviate from each other. A positive excursion of several permil in δ13Corg starts earlier and is much more pronounced than the short-term positive δ13Ccarb excursion; both excursions interrupt the general negative trend. Throughout the entire period investigated, δ13Corg values become lighter with increasing distance from the palaeocoastline. Changing δ13Corg values may be due to the influx of comparatively isotopically heavy land plant material. The stronger influence of land plant material on the δ13Corg during the positive isotope excursion indicates a temporarily enhanced continental runoffthat may either reflect increased precipitation, possibly triggered by aerosols originating from Siberian Trap volcanism, or indicate higher erosion rate in the face of reduced land vegetation cover. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Korte C.,Free University of Berlin | Pande P.,University of Delhi | Kalia P.,University of Delhi | Kozur H.W.,Rezsu u. 83 | And 2 more authors.
Journal of Asian Earth Sciences

Bulk carbonate and conodonts from three Permian-Triassic (P-T) boundary sections at Guryul Ravine (Kashmir), Abadeh (central Iran) and Pufels/Bula/Bulla (Italy) were investigated for δ13C and δ18O. Carbon isotope data highlight environmental changes across the P-T boundary and show the following features: (1) a gradual decrease of ∼4‰ to more than 7‰ starting in the Late Permian (Changhsingian) C. bachmanni Zone, with two superimposed transient positive excursions in the C. meishanensis-H. praeparvus and the M. ultima-S. ? mostleri Zones; (2) two δ13C minima, the first at the P-T boundary and a higher, occasionally double-minimum in the lower I. isarcica Zone. It is unlikely that the short-lived phenomena, such as a breakdown in biological productivity due to catastrophic mass extinction, a sudden release of oceanic methane hydrates or meteorite impact(s), could have been the main control on the latest Permian carbon isotope curve because of its prolonged (0.5 Ma) duration, gradual decrease and the existence of a >1‰ positive shift at the main extinction horizon. The P-T boundary δ13C trend matches in time and magnitude the eruption of the Siberian Traps and other contemporaneous volcanism, suggesting that volcanogenic effects, such as outgassed CO2 from volcanism and, even more, thermal metamorphism of organic-rich sediments, as the likely cause of the negative trend. © 2009 Elsevier Ltd. All rights reserved. Source

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