U-Pb age constraints on dinosaur rise from south Brazil

Autor(es)

Langer, Max C. ^[1] ; Ramezani, Jahandar ^[2] ; Da Rosa, Atila A. S. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Biol FFCLRP, BR-14040180 Ribeirao Preto, SP - Brazil

^[2] MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 - USA

^[3] Univ Fed Santa Maria, Dept Geociencias, BR-97105900 Santa Maria, RS - Brazil

• Tipo de documento: Artigo Científico
• Fonte: GONDWANA RESEARCH; v. 57, p. 133-140, MAY 2018.
• Citações Web of Science: 27

Resumo

Triassic dinosaurs from South Brazil are considered as some of the oldest known worldwide, but their precise correlation to other early dinosaur occurrences have proven difficult. The problem of such long-distance faunal correlations has been exacerbated by reliance on an equivocal tetrapod biostratigraphy and the lack of palynomorphs and other age-bearing microfossils. Here, we present new high-precision U-Pb zircon geochronology (CA-ID-TIMS method) from two classical dinosaur-bearing fossil sites in south Brazil; a weighted mean Pb-206/U-238 date of 233.23 +/- 0.73 Ma (2 sigma complete uncertainty) from the Santa Maria Formation and a single zircon Pb-206/U-238 date of 225.42 +/- 0.37 Ma representing the maximum age of the Caturrita Formation. The new age results, combined with available geochronology from other Triassic dinosauromorph occurrences, allow establishing a chronostratigraphic framework for the Late Triassic appearance of dinosaurs in western Pangea. Within this context, the major macroevolutionary events associated with the rise of dinosaurs can be recognized and their possible links to coeval paleoenvironmental and biotic shifts can be examined. (C) 2018 International Association for Gondwana Research. Published by Elsevier B.V. All rights,reserved. (AU)

• Processo FAPESP: 14/03825-3 - A origem e irradiação dos dinossauros no Gondwana (Neotriássico - Eojurássico)
• Beneficiário: Max Cardoso Langer
• Modalidade de apoio: Auxílio à Pesquisa - Temático