نتایج جستجو برای: early triassic
تعداد نتایج: 688914 فیلتر نتایج به سال:
Authigenic carbonate was recently invoked as a third major global carbon sink in addition to primary marine carbonate and organic carbon. Distinguishing the two carbonate sinks is fundamental to our understanding of Earth's carbon cycle and its role in regulating the evolution of atmospheric oxygen. Here, using microscale geochemical measurements of carbonates in Early Triassic strata, we show ...
To discern the effect of the end-Permian (P-Tr) ecological crisis on land, interactions between plants and their insect herbivores were examined for four time intervals containing ten major floras from the Dolomites of northeastern Italy during a Permian-Triassic interval. These floras are: (i) the Kungurian Tregiovo Flora; (ii) the Wuchiapingian Bletterbach Flora; (iii) three Anisian floras; a...
Today’s trip traverses a nearly east-west swath of the southern Colorado Plateau in northeatern Arizona (Fig. 2.1), where the low and barren topography is developed in Permian and Triassic sedimentary rocks. Here, our focus is on the Lower-Middle Triassic Moenkopi Formation. In northern Arizona, east of Flagstaff, the Moenkopi section (Fig. 2.2) is a relatively thin (< 150 m thick) and almost e...
The Great Bank of Guizhou (GBG) is an isolated Late Permian to Late Triassic carbonate platform in the Nanpanjiang Basin of Guizhou Province, southwest China. A faulted syncline exposes a cross section of the platform margin, including a well-preserved Anisian (earliest Middle Triassic) reef complex approximately 1 km wide and 800 meters thick. Geochronologic constraints from associated basin-m...
The timing and nature of biotic recovery from the devastating end-Permian mass extinction (252 Ma) are much debated. New studies in South China suggest that complex marine ecosystems did not become re-established until the middle-late Anisian (Middle Triassic), much later than had been proposed by some. The recently discovered exceptionally preserved Luoping biota from the Anisian Stage of the ...
A new genus and species of pycnodontiform fishes, Grimmenodon aureum, from marginal marine, marine-brackish lower Toarcian (Harpoceras exaratum ammonite subzone) clay deposits of Grimmen in northeastern Germany is described. The single specimen represents a diagnostic left prearticular dentition characterized by unique tooth arrangement and ornamentation patterns. Grimmenodon aureum, gen. et sp...
The origin of the limbless caecilians remains a lasting question in vertebrate evolution. Molecular phylogenies and morphology support that caecilians are the sister taxon of batrachians (frogs and salamanders), from which they diverged no later than the early Permian. Although recent efforts have discovered new, early members of the batrachian lineage, the record of pre-Cretaceous caecilians i...
Iron ore occurrences are situated on the south-eastern slopes of the Medvednica Mountain. They occur as discontinous, decameters long and 2-3.5 m thick bedded, poorly mineralized (15-35 % Fe) lenses. A narrow, 6 km long, ore zone strikes NE-SW from Tisova Peć to Pustodol-Adolfovac. It is spatially and genetically bounded to the basic volcanogenic-sedimentary series (SEDEX-type), metamorphosed i...
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