Dating the origin of dinosaurs

The African cynodont Aleodon (Cynodontia, Probainognathia) in the Triassic of southern Brazil and its biostratigraphic significance

“…As was briefly commented on by Sues [124] and Martinelli and Soares [4], the tetrapod composition of the Río Seco de la Quebrada Formation is highly bizarre when compared to other basins from South America (i.e., Ischigualasto-Villa Unión Basin in Argentina and Paraná Basin in Brazil). Even if the hypothesis of Ottone et al [106] is accepted, in which the biochron of Cynognathus and Diademodon is longer than the African one, the absence of both genera in other well-sampled basins of Argentina and Brazil of early Carnian age would be a remarkably aberrant distribution (Fig 19).…”

“…Based upon the dates from the Puesto Viejo Group [ 106 ] and those from the Cerro de Las Cabras Formation (Cuyana Basin; [ 121 – 122 ]), biostratigraphic correlations between both units are quite problematic and do not fit with previous faunistic interpretations (e.g., [ 10 , 117 , 123 ]), especially because of the occurrence of Cynognathus and Diademodon in the supposed early Carnian Río Seco de la Quebrada Formation. As was briefly commented on by Sues [ 124 ] and Martinelli and Soares [ 4 ], the tetrapod composition of the Río Seco de la Quebrada Formation is highly bizarre when compared to other basins from South America (i.e., Ischigualasto-Villa Unión Basin in Argentina and Paraná Basin in Brazil). Even if the hypothesis of Ottone et al [ 106 ] is accepted, in which the biochron of Cynognathus and Diademodon is longer than the African one, the absence of both genera in other well-sampled basins of Argentina and Brazil of early Carnian age would be a remarkably aberrant distribution ( Fig 19 ).…”

A new early‐diverging probainognathian cynodont and a revision of the occurrence of cf. Aleodon from the Chañares Formation, northwestern Argentina: New clues on the faunistic composition of the latest Middle–?earliest Late Triassic Tarjadia Assemblage Zone

“…In the last years, fossils from the late Middle to earliest Late Triassic of Argentina, Brazil, Tanzania, and Namibia have strengthened faunal similarities, even at generic or specific level, among several tetrapod groups (Abdala, Marsicano, et al, 2013; Escobar et al, 2021; Ezcurra et al, 2017; Ezcurra, Fiorelli, et al, 2021; Ezcurra et al, 2014; Martinelli, Kammerer, et al, 2017; Melo et al, 2022; Melo et al, 2019; Mocke et al, 2020; Nesbitt & Desojo, 2017; Paes‐Neto et al, 2024; Peecook et al, 2013; Schmitt et al, 2019; Wynd et al, 2017). Despite these strong faunal similarities, the data obtained by radiometric dates does not always fit to the biostratigraphic scheme (see discussions in Abdala et al, 2020; Ezcurra et al, 2017; Ezcurra, Fiorelli, et al, 2021; Martinelli & Soares, 2016; Martinelli, Kammerer, et al, 2017; Novas et al, 2021; Sues, 2016).…”

Nanoscale Spatially Resolved Mapping of Uranium Enrichment in Actinide-Bearing Materials

“…Uranium (U) is the heaviest element naturally occurring in the Earth's crust in significant amounts, and is used both in its natural, processed, and anthropogenic forms. U isotopes are central to a diverse set of scientific disciplines, most notably earth and planetary sciences [1][2][3][4][5][6][7][8], toxicology, environmental monitoring and bioremediation [9][10][11], and the nuclear fuel cycle, forensics, and safeguards [12][13][14][15][16][17][18][19][20][21][22]. Specifically in nuclear fuel cycle applications, the amount of the fissionable U isotope ( 235 U) relative to all U (defined as enrichment) is a critical parameter in fuel performance, and thus impacts economic viability of nuclear power.…”