نتایج جستجو برای: paleozoic

تعداد نتایج: 1972  

2013
MICHAEL JAMES DELUCA

Wrangellia Superterrane. The Paleozoic to Mesozoic Wrangellia superterrane (Insular terrane) consists of intraoceanic volcanic assemblages and basement rocks of the Peninsular, Wrangellia, and Alexander terranes (Plafker et al, 1994). The magmatic-arc assemblages of the Peninsular terrane appear to have been built upon the Wrangellia composite terrane prior to the midCretaceous and include: 1) ...

Journal: :Systematic biology 2009
Nadia B Fröbisch Rainer R Schoch

Among the diverse clade of Paleozoic dissorophoid amphibians, the small, terrestrial amphibamids and the neotenic branchiosaurids have frequently been suggested as possible antecedents of either all or some of the modern amphibian clades. Classically, amphibamids and branchiosaurids have been considered to represent distinct, but closely related clades within dissorophoids, but despite their im...

2018
Alain Le Hérissé Edwige Masure Emmanuelle J. Javaux Craig P. Marshall ALAIN LE HERISSE EDWIGE MASURE EMMANUELLE J. JAVAUX CRAIG P. MARSHALL

Arpylorus antiquus, erected by Calandra (1964), was isolated from Upper Silurian sedimentary rocks from the Mechiguig-1 borehole in southern Tunisia, with other palynomorphs. The folded vesicle and the quadrangular form of the aperture breaks down into plate-like fragments, resembling the tabulation of dinoflagellates. The presence of these elements, have been used to interpret A. antiquus as a...

2017
Mariusz A. Salamon Przemysław Gorzelak

Thuy et al. (2017) meant to present evidence that some Paleozoic stem-group echinoderms survived the end-Permian extinction. If valid, this would be an important discovery because it radically challenges severe evolutionary bottleneck experienced by echinoderms during that time. However, given the far-reaching implications of such a matter, the onus and burden of proof must be high and applied....

2013
Sh. M. Talaat F. Ragab T. M. Abd El Maksoud

This paper spotlights on determining the concentrations and distribution of radionuclides in paleozoic lateritic paleosol samples from El-Gor area, southwestern Sinai, Egypt, using high-resolution gamma spectrometry. The concentrations of eU (ppm), eTh (ppm), and K (in percentage) were determined. The obtained data of eU, eTh and their ratios were used for calculations of uranium migration tend...

Journal: :Meteoritics & Planetary Science 2019

Journal: :Proceedings of the National Academy of Sciences 1992

Journal: :Russian Journal of Earth Sciences 2006

Journal: :Proceedings of higher educational establishments. Geology and Exploration 2019

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