The age of the Tunas formation in the Sauce Grande basin-Ventana foldbelt (Argentina): Implications for the Permian evolution of the southwestern margin of Gondwana |
| |
| Institution: | 1. Instituto de Investigación en Paleobiología y Geología, UNRN-CONICET, Av. Julio A. Roca 1242, R 8332 EXZ, General Roca, Río Negro, Argentina;2. Centro de Investigaciones Geológicas, UNLP-CONICET, Diagonal 113 N° 275, B 1904 DPK, La Plata, Buenos Aires, Argentina;3. Instituto de Estudios Andinos “Don Pablo Groeber”, UBA-CONICET, Güiraldes 2160, Ciudad Universitaria, Pabellón II, C 1428 EHA, Buenos Aires, Argentina;4. Centro de Pesquisas Geocronológicas, Instituto de Geociências, USP, Rua do Lago 562, CEP 05508-080 São Paulo, SP, Brazil;5. GEO-Departamento de Geologia Geral e Aplicada, Instituto de Geociências, Universidade de Brasília, ICC-Centro, Campus Universitário Darcy Ribeiro Asa Norte, CEP 70910-900, Brazil;6. Departamento de Geología, Universidad de Huelva, Campus del Carmen, 21071 Huelva, Spain |
| |
| Abstract: | New SHRIMP radiogenic isotope dating on zircons in tuffs (280.8 ± 1.9 Ma) confirms the Early Permian (Artinskian) age of the uppermost section of the Tunas Formation. Tuff-rich levels in the Tunas Formation are exposed in the Ventana foldbelt of central Argentina; they are part of a deltaic to fluvial section corresponding to the late overfilled stage of the Late Paleozoic Sauce Grande foreland basin. Recent SHRIMP dating of zircons from the basal Choiyoi volcanics exposed in western Argentina yielded an age of 281.4 ± 2.5 Ma (Rocha-Campos et al., 2011). The new data for the Tunas tuffs suggest that the volcanism present in the Sauce Grande basin can be considered as the distal equivalent of the earliest episodes of the Choiyoi volcanism of western Argentina. From the palaeoclimatic viewpoint the new Tunas SHRIMP age confirms that by early Artinskian glacial conditions ceased in the Sauce Grande basin and, probably, in adajacent basins in western Gondwana. |
| |
| Keywords: | Gondwana Permian Tuffs Plate margin volcanism |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
