Artículo
Abstract:
A new paleomagnetic study was carried out on 15 sites of the Sierra de las Ánimas complex, exposed in SE Uruguay. A paleomagnetic remanence was isolated at six sites, and this direction is likely to be pre-tectonic and primary. Mean directions from five of these sites are consistent with the SA2 paleomagnetic pole, which is based on a previous paleomagnetic study of the complex. A new paleomagnetic pole was computed for compiled results from the Sierra de las Ánimas complex (SAn, 12.2°. S, 258.9°. E, A95: 14.9°). A geochronological study based on U/Pb (SHRIMP) dating of magmatic zircons was also carried out on three samples of the Sierra de las Animas Complex, yielding a grand mean age of 578. ±. 4. Ma. The new SAn paleomagnetic pole anchors the Early Ediacaran segment of the Apparent Polar Wander Path for the Ri´o de la Plata craton. Consistency of the new pole with other Ediacaran poles from the Congo-São Francisco craton suggests a coherent Central Gondwana by this time. These data also support a wide Clymene Ocean between the conjoined Ri´o de la Plata-Congo-São Francisco blocks and Western Gondwana, i.e., Amazonia-West Africa. Additional sampling (sixteen samples) was carried out on the basal levels of the glaciogenic Playa Hermosa Formation, exposed in the same area. These samples retain a paleomagnetic component consistent with the previously reported data, confirming the original pole position. U-Pb (SHRIMP) dating of detrital zircons reveal a bimodal distribution of Paleoproterozoic (around 2.1. Ga) and late Neoproterozoic ages. The youngest zircons are interpreted as pre-dating to penecontemporaneous with deposition and points to a ≤594. Ma age for deposition of the older levels of the Playa Hermosa Formation. A minimum age of deposition is set by the 578. ±. 4. Ma age of the Sierra de las Ánimas magmatism. The low inclination of magnetization indicates that low-latitude (13.0°. +. 9.5°/-5.5°), Gaskiers-aged glacial deposits are preserved atop the Rio de la Plata craton. © 2014 Elsevier B.V.
Registro:
| Documento: | Artículo |
| Título: | The late Neoproterozoic Sierra de las Ánimas Magmatic Complex and Playa Hermosa Formation, southern Uruguay, revisited: Paleogeographic implications of new paleomagnetic and precise geochronologic data |
| Autor: | Rapalini, A.E.; Tohver, E.; Bettucci, L.S.; Lossada, A.C.; Barcelona, H.; Pe´rez, C. |
| Filiación: | Laboratorio de Paleomagnetismo Daniel A. Valencio, Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires (IGEBA), Departamento de Cs. Geologicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina University of Western Australia, Australia Laboratorio de Geofi´sica y Geotecto´nica, Departamento de Geologi´a, Facultad de Ciencias, Universidad de la Repu´blica, Uruguay IANIGLA (Instituto Argentino de Nivologi´a, Glaciologi´a y Ciencias Ambientales), CCT-Mendoza, CONICET, Argentina Instituto de Geocronologi´a y Geologi´a Isoto´pica (INGEIS), UBA-CONICET, Buenos Aires, Argentina |
| Palabras clave: | Gondwana; Paleomagnetism; Ri´o de la Plata craton; South America; Uruguay |
| Año: | 2014 |
| DOI: | http://dx.doi.org/10.1016/j.precamres.2014.11.021 |
| Título revista: | Precambrian Research |
| Título revista abreviado: | Precambrian Res. |
| ISSN: | 03019268 |
| CODEN: | PCBRB |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_03019268_v_n_p_Rapalini |
Citas:
---------- APA ----------
Rapalini, A.E., Tohver, E., Bettucci, L.S., Lossada, A.C., Barcelona, H. & Pe´rez, C. (2014) . The late Neoproterozoic Sierra de las Ánimas Magmatic Complex and Playa Hermosa Formation, southern Uruguay, revisited: Paleogeographic implications of new paleomagnetic and precise geochronologic data. Precambrian Research.http://dx.doi.org/10.1016/j.precamres.2014.11.021
---------- CHICAGO ----------
Rapalini, A.E., Tohver, E., Bettucci, L.S., Lossada, A.C., Barcelona, H., Pe´rez, C. "The late Neoproterozoic Sierra de las Ánimas Magmatic Complex and Playa Hermosa Formation, southern Uruguay, revisited: Paleogeographic implications of new paleomagnetic and precise geochronologic data" . Precambrian Research (2014).http://dx.doi.org/10.1016/j.precamres.2014.11.021
---------- MLA ----------
Rapalini, A.E., Tohver, E., Bettucci, L.S., Lossada, A.C., Barcelona, H., Pe´rez, C. "The late Neoproterozoic Sierra de las Ánimas Magmatic Complex and Playa Hermosa Formation, southern Uruguay, revisited: Paleogeographic implications of new paleomagnetic and precise geochronologic data" . Precambrian Research, 2014.http://dx.doi.org/10.1016/j.precamres.2014.11.021
---------- VANCOUVER ----------
Rapalini, A.E., Tohver, E., Bettucci, L.S., Lossada, A.C., Barcelona, H., Pe´rez, C. The late Neoproterozoic Sierra de las Ánimas Magmatic Complex and Playa Hermosa Formation, southern Uruguay, revisited: Paleogeographic implications of new paleomagnetic and precise geochronologic data. Precambrian Res. 2014.http://dx.doi.org/10.1016/j.precamres.2014.11.021
