نتایج جستجو برای: permian system
تعداد نتایج: 2233955 فیلتر نتایج به سال:
Anomodontia was a highly successful tetrapod clade during the Permian and the Triassic. New morphological information regarding two bizarre basal anomodonts is provided and their palaeoecological significance is explored. The osteology of the recently discovered Tiarajudens eccentricus Cisneros et al. 2011, from the Brazilian Permian, is described in detail. The taxon exhibits unusual postcrani...
As the most diverse group of early tetrapods, temnospondyls provide a unique opportunity to investigate cladogenetic patterns among basal limbed vertebrates. We present five species-level supertrees for temnospondyls, built using a variety of methods. The standard MRP majority rule consensus including minority components shows slightly greater resolution than other supertrees, and its shape mat...
The greatest loss of biodiversity in the history of animal life occurred at the end of the Permian Period (∼252 million years ago). This biotic catastrophe coincided with an interval of widespread ocean anoxia and the eruption of one of Earth’s largest continental flood basalt provinces, the Siberian Traps. Volatile release from basaltic magma and sedimentary strata during emplacement of the Si...
Although Siberian Trap volcanism is considered a primary driver of the largest extinction in Earth history, the end-Permian crisis, the relationship between these events remains unclear. However, malformations in fossilized gymnosperm pollen from the extinction interval suggest biological stress coinciding with pulsed forest decline. These grains are hypothesized to have been caused by enhanced...
[1] A series of sharp bends (oroclines) are recognized in the Paleozoic to early Mesozoic New England Orogen of eastern Australia. The exact geometry and origin of these bends is obscured by voluminous magmatism and is still debated. Here we present zircon U-Pb ages that confirm the lateral continuation of early Permian (296–288 Ma) granitoids and shed new light on the oroclinal structure. Orog...
The association between the Siberian Traps, the largest continental flood basalt province, and the largest-known mass extinction event at the end of the Permian period, has been strengthened by recently-published high-precision Ar/Ar dates from widespread localities across the Siberian province. We argue that the impact of the volcanism was amplified by the prevailing late Permian environmental...
A new ichnogenus and ichnospecies of burrow, Katbergia carltonichnus, are described from Upper Permian and Lower Triassic rocks of the Karoo Basin, South Africa, where they are preserved in pedogenically modified overbank deposits that are interpreted as inceptisols subsequently gleysol overprinted. Sigmoidal burrows consist of a long (‡0.5 m) cylindrical tube, ranging from 1–2 cm in diameter, ...
Belmophenopterum rasnitsyni sp. n. is described from the Middle Triassic Madygen locality in Kyrgyzstan. It latest record of genus Rasnitsyn et Aristov, 2004. The Permian Sylviodes Martynov, 1940 and Permian-Triassic are transferred family Sylvaphlebiidae (Reculida) to Mesorthopteridae (Eoblattida).
Manuscrito ID: 30163. Recebido em: 19/09/2014. Aprovado em: 19/09/2014. ABSTRACT: New lines of geological evidence strongly suggest that the main period of hydrocarbon maturation within Assistência Formation should be Permian-Triassic, stimulated by a high geothermal gradient that also sustained various manifestations of hydrothermal activity. Three main stages of fluid/hydrocarbon migration ca...
Previous studies have suggested a variety of causes for the end-Permian extinction event including a bolide impact, flood basalt volcanism, methane clathrate dissociation, or some combination of catastrophic processes. One common feature of these hypotheses is the prediction of an enhanced earliest Triassic greenhouse. New high-resolution geochemical results from Graphite Peak, Antarctica suppo...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید