Paleomagnetism of the late Cenozoic basalts from northern Patagonia

Abstract

Late Cenozoic volcanic rocks outcrop in the northern Patagonia Extrandina. Lava flows, characterized as olivine and alkaline basalts, belong to intraplate volcanism. We report paleomagnetic and rock-magnetic studies carried out on Late Cenozoic basalts belonging to the Cráter, Mojón and Moreniyeu Formations. The paleomagnetic sampling comprised 75 sites in lava flows and dikes from the Cráter Formation, three sites in a lava flow from the Mojón Formation and three sites in a lava flow from the Moreniyeu Formation. Alternating field (AF) and thermal detailed demagnetization techniques were used. Most of the samples have a viscous component. The AF procedure was more effective than thermal demagnetization in destroying viscous components and in defining the characteristic remanent magnetizations. Demagnetization curves and rock-magnetic studies suggest that the main remanence carrier is Ti-poor magnetite. Radiometric K-Ar ages were performed on these basalts. The radiometric ages are 0.8±0

Paleomagnetism of early cretaceous arapey formation (Northern Uruguay)

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Miocene block uplift and basin formation in the Patagonian foreland: The Gastre Basin, Argentina

“…3), grouped in the Moreniyeu and Cráter Formations (Proserpio, 1978;Ravazzoli and Sesana, 1977). The stratigraphic relationships between the sedimentary and volcanic units, as well as the isotopic ages of the basaltic lavas (1.9 to 0.23 Ma; Haller et al, 2009;Mena et al, 2006;Pécskay et al, 2007), constrain the Quaternary formations to the lower-Middle Pleistocene. Holocene and recent alluvial and fluvial deposits (Fig.…”

The late Eocene–early Miocene El Maitén Belt evolution: Magmatic response to the changing subduction zone geodynamics

“…However, plutonism is also registered to the east, in the foreland zone, which was accompanied by deformation, uplift, and the eastward migration of the foreland basins (Orts et al, 2012). This event was presumably interpreted as another shallow subduction event in the area (Orts et al, 2015) that ended with a steepening and the development of Pliocene-Pleistocene within plate magmatism in the retroarc zone (Haller et al, 2009;Massaferro et al, 2006;Mena et al, 2006;P� ecskay et al, 2007). Finally, recent arc volcanism is developed in the main Andes, in a strong relationship with the Liquiñe-Ofqui fault zone that controls its emplacement (Cembrano and Lara, 2009;Lopez-Escobar et al, 1993).…”