نتایج جستجو برای: permian
تعداد نتایج: 3143 فیلتر نتایج به سال:
The Permian ended with the largest of known mass extinctions in the history of life. This signal event has been difficult to recognize in Antarctic non-marine rocks, because the boundary with the Triassic is defined by marine fossils at a stratotype section in China. Late Permian leaves (Glossopteris) and roots Vertebraria), and Early Triassic leaves (Dicroidium) and vertebrates (Lystrosaurus) ...
Studies of the end-Permian mass extinction have emphasized potential abiotic causes and their direct biotic effects. Less attention has been devoted to secondary extinctions resulting from ecological crises and the effect of community structure on such extinctions. Here we use a trophic network model that combines topological and dynamic approaches to simulate disruptions of primary productivit...
The Fistulipora microparallela (Yang and Lu, 1962) species is described for the first time from the Sakmarian deposits of the Sarab section in Lut Block, Central Iran. This species has been reported only from the Permian (Cisuralian-Guadalupian) of the Qilianshan and Kankerin formations, and the Baliqliq Group (Upper Carboniferous to Lower Permian) of Western Xinjiang, China.
The family Mesopanorpodidae is revised. Most taxa referred to this family are not related to the type genus Mesopanorpodes Tillyard, 1918. The type species of the latter, Mesopanorpodes wianamattensis,is closely related to Mesopsyche Tillyard, 1917. Therefore Mesopanorpodes is transferred to Mesopsychidae Tillyard, 1917 (= Mesopanorpodidae Tillyard, 1918, syn. n.).The earliest Mesopsychidae are...
A new replacement name Permulidaenom. n. is proposed for the Permian family Aliculidae Storozhenko, 1997 (Insecta: Grylloblattida). A review of Permulidae is given. All genera and species are redescribed and illustrated. A key to genera of Permulidae is given. New taxa of Permulidae are described: Permula edemskiisp. n., Sojanopermula rasnitsynisp. n., Kazanalicula reductagen. et sp. n., Mezena...
Multiple chondritic meteorite fragments have been found in two sedimentary rock samples from an end-Permian bed at Graphite Peak in Antarctica. The Ni/Fe, Co/Ni, and P/Fe ratios in metal grains; the Fe/Mg and Mn/Fe ratios in olivine and pyroxene; and the chemistry of Fe-, Ni-, P-, and S-bearing oxide in the meteorite fragments are typical of CM-type chondritic meteorites. In one sample, the met...
The upper carbonate member of the Kaibab Formation in northern Arizona (USA) was subaerially exposed during the end Permian and contains fractured and zoned chert rubble lag deposits typical of karst topography. The karst chert rubble has secondary (authigenic) silica precipitates suitable for estimating continental weathering temperatures during the end Permian karst event. New oxygen and hydr...
a totall of 500 early permian samples from the chal-i-sheh formation in the zagros basin were examined palynollogically in order to determine the stratigraphical age of the formation and to assess the palaeogeopaphicd relatianships of this basin to the southern and northern hemispheres during the early permian. fifty-eight taxa were recorded including 46 pollen, 10 spore and 2 acritarch species...
Three new palaeopteran insects are described from the Middle Permian (Guadalupian) of Salagou Formation in the Lodève Basin (South of France), viz. the diaphanopterodean Alexrasnitsyniidaefam. n., based on Alexrasnitsynia permianagen. etsp. n., the ParelmoidaePermelmoa magnificagen. etsp. n., and Lodevohymen lapeyrieigen. etsp. n. (in Megasecoptera or Diaphanopterodea, family undetermined). In ...
—The small size of Early Triassic marine organisms has important implications for the ecological and environmental pressures operating during and after the end-Permian mass extinction. However, this “Lilliput Effect” has only been documented quantitatively in a few invertebrate clades. Moreover, the discovery of Early Triassic gastropod specimens larger than any previously known has called the ...
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