Paleomagnetism of the Ediacaran Avellaneda Formation (Argentina), part I: Paleogeography of the Rio de la Plata craton at the dawn of Gondwana

Author(s)

Franceschinis, P. R. ; Afonso, J. W. ; Arrouy, M. J. ; Gomez-Peral, L. E. ; Poire, D. ; Trindade, R. I. F. ; Rapalini, A. E.

• Document type: Journal article
• Source: Precambrian Research; v. 383, p. 27-pg., 2022-12-01.

Abstract

A paleomagnetic and rock magnetic study was carried out in the Ediacaran Avellaneda (similar to 570 Ma) and Cerro Negro (similar to 555 Ma) Formations belonging to the La Providencia Group, in the upper part of the Neoproterozoic sedimentary cover of the Tandilia region, in the Rio de la Plata craton. The Avellaneda Formation was studied at outcrop level and in three drill cores, yielding a mean characteristic remanence direction of Dec: 21.4 degrees, Inc: 67.1 degrees, alpha(95): 4.2 degrees, k: 23.9, N: 51 and a paleomagnetic pole at 1.0 degrees S, 313.4 degrees E, A(95): 5.9 degrees. The Cerro Negro Formation yielded a mean characteristic direction of Dec: 22.0 degrees, Inc: 68.5 degrees, alpha(95): 10.3 degrees, k: 20.8, N: 11 obtained from a single drill core, from which a paleomagnetic pole at 3.6 degrees S, 307.8 degrees E, A(95): 16.6 degrees was computed. Rock magnetic data indicates that magnetic remanence is mainly associated with magnetite and hematite. The paleomagnetic information presented here results in a change in the previously accepted Late Ediacaran apparent polar wander path of the Rio de la Plata Craton. The newly obtained poles indicate that Rio de la Plata Craton experienced a rapid drift from a low latitudes location (ca. 19 degrees S) at ca. 600 Ma to moderately higher latitudes (between 50 degrees and 42 degrees S) from around 580 to 550 Ma. (AU)

• FAPESP's process: 16/06114-6 - The Neoproterozoic Earth System and the rise of biological complexity
• Grantee: Ricardo Ivan Ferreira da Trindade
• Support Opportunities: Research Projects - Thematic Grants