Paleomagnetic directions from mid-latitude sites in the southern hemisphere (Argentina): Contribution to time averaged field models

Abstract

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Geochronology of the late Pliocene to recent volcanic activity in the Payenia back-arc volcanic province, Mendoza Argentina

“…The youngest activity in the Pampas Negras and Los Volcanes area is known as the Media Luna basalts (Llambías, 1966) of Late Holocene age (Españon, 2010). A few scattered occurrences of older lava flows in the area north of Los Volcanes and Pampas Negras are found and one was dated by Quidelleur et al (2009) to 1.72 AE 0.05 Ma. Also the basaltic activity in the eastern part of the Carbonilla fracture has apparently continued since before 0.4 AE 0.1 Ma according to the age of the Carrizales flow which was derived from this fracture (Melchor and Casadío, 1999;Pasquaré et al, 2008).…”

“…Detailed radiometric age studies were few up until a few years ago. Recent papers have published ages from different segments of the province (Folguera et al, 2009;Germa et al, 2010;Kay et al, 2006aKay et al, , 2006bQuidelleur et al, 2009). We present 18 new radiometric ages obtained by the 40 Ar/ 39 Ar method on rocks from the whole volcanic province with special focus on spatial and temporal trends in the volcanic activity for the last w3 Ma.…”

“…The inset shows the location of the studied area in South America; CR is the Chile Ridge, CFZ the Challenger fracture zone, and CT the Chile trench. Data sources: this work, Kay et al (2006a), Folguera et al (2009), Germa et al (2010) Quidelleur et al, 2009, and Españon (2010. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.…”

Cosmogenic 3He and 21Ne surface exposure dating of young basalts from Southern Mendoza, Argentina

“…Even though many of the available chronological data for past eruptive activity have mainly provided mid-to late Pleistocene ages (Quidelleur et al, 2009;Germa et al, 2010;Gudnason et al, 2012;Marchetti et al, 2013), much younger volcanic activity (i.e., less than 10 ka) in the ACBP has been inferred based on geomorphic analysis (Inbar and Risso, 2001a) and a recent Ne dating when applied to Holocene volcanic rocks, thereby (ii) testing a possible practical younger limit of the north and the Payunia Volcanic Field (PVF) to the south (Bermúdez and Delpino, 1989). …”

“…The back-arc volcanism of the ACBP was caused by a steepening of the subducting slab, which introduced hot asthenospheric upwelling associated with melting of hydrated mantle (Stern, 2004;Quidelleur et al, 2009;Germa et al, 2010). The ACBP is dominated by basaltic and basaltic-andesitic flows.…”