New paleomagnetic data from the northern Puna and western Cordillera Oriental, Argentina: a new insight on the timing of rotational deformation

Magnetostratigraphy of the Miocene Las Arcas Formation, Santa María Valley, northwestern Argentina

“…Lack of significant Andean tectonic rotations in this area reinforces previous ideas (Aubry et al 1996;de Urreiztieta et al 1996;Beck 1998;Taylor et al 1998;Coutand et al 1999;Spagnuolo et al 2010;Zambrano et al 2010;Ré et al 2001;Japas and Ré 2006;Japas and Ré 2012;Vizán et al 2013) that rotations in this region do not follow a simple and uniform pattern. Beck (1998), Prezzi et al (2004), Japas and Ré (2012) and Somoza and Tomlinson (2002) claim that no significant rotation should be expected in the region since 10 Ma. Therefore, older rotations in our study area cannot be excluded.…”

Mineralogical changes during thermal demagnetization of natural continental sandstones

“…Tiomayo Formation consists mainly of ignimbrites, tuffaceous sandstones, conglomerates, shales and tuffs. Three different sections are identified in Tiomayo Formation: the lower reddish section, the middle yellowish section and the upper greenish section (Prezzi et al, 2004). The whole sequence is a thinning-and fining-upward succession, which changes from red conglomerates and sandstones at the base to mostly yellow and greenish mudstones at the top.…”

“…The upper member of the Tiomayo Formation (70 m thick) is green coloured, and starts with massive sandstones that laterally passes to eolianites showing large-scale cross bedding. The last 40 m of the section are characterized by the presence of biotitic air-fall tuffs and reworked pyroclastic deposits, interbedded with tuffaceous, carbonatic mudstones and lutites (Prezzi et al, 2004). The section was formed in a playa lake environment surrounded by active volcanoes and thermal springs and contains travertine and borates (Prezzi and Alonso, 2002).…”

“…These samples were paleomagnetically studied previously (Prezzi and Vilas, 1998;Prezzi and Alonso, 2002;Prezzi et al, 2004) and showed dramatic bulk magnetic susceptibility increases during high-temperature demagnetization in air. Different analyses and experiments were performed.…”

The Southern Central Andes vertical axis tectonic rotations: relations with the deformation pattern

“…Local models have also been proposed, but they are focused in the forearc (e.g., Forsythe and Chisholm, 1994;Taylor et al, 1998;Abels and Bischoff, 1999;Arriagada et al, 2003;Taylor et al, 2005). Recently, the quantity, quality, and geographic distribution of paleomagnetic data have expanded greatly (Richards et al, 2004;Prezzi et al, 2004;Arriagada et al, 2006;Roperch et al, 2006;Taylor et al, 2007;Barke and Lamb, 2007;Arriagada et al, 2008b;Maffione et al, 2009). The increased paleomagnetic data set has been accompanied by an increase in the current knowledge of the deformation periods in the Andes (e.g., Oncken et al, 2006;Ege et al, 2007;Hongn et al, 2007;Barnes and Ehlers, 2009), allowing a more detailed analysis of the temporal and spatial distribution of the detected rotations.…”