Vertical-axis rotations and deformation along the active strike-slip El Tigre Fault (Precordillera of San Juan, Argentina) assessed through palaeomagnetism and anisotropy of magnetic susceptibility

Abstract

susceptibility data to show that the local strain regime suggests a N-S stretching direction, subparallel to the strike of the main fault.

Subsurface characterization of quaternary scarps and their possible connection to main structures of the western margin of Precordillera, San Juan, Argentina

“…On the other hand, main piedmont structure, the El Tigre Fault, represents a dextral strike-slip fault with vertical component determined by observations in trenches (Bastías et al 1984, Bastías 1985INPRES, 1982;Siame 1998), and ERTs (Fazzito et al, 2013). This fault has been active since the Pliocene (Fazzito et al, 2016) until Holocene times (Siame et al, 1997 a, b), as established from paleomagnetic studies and cosmogenic dating, respectively. Other regional structures affecting the study region are ~NW-SE J o u r n a l P r e -p r o o f lineaments (Figure 2) that obliquely intersect the El Tigre Fault without evident offsets, and are related to subvertical faults with a possible sinistral strike-slip kinematics as determined from ERTs (Peri et al, 2017).…”

“…Moreover, the strike-slip movement of El Tigre Fault has been initiated at Pliocene (Fazzito et al, 2016) continued during the Holocene (Siame et al, 1997a, b), so the partition of deformation in the western margin of Precordillera is probably active during Quaternary until today.…”

“…Other regional structures in the study area are ~NW-SE to NNW-SSE lineaments and inferred fault trace (Figure 2a; Fazzito et al, 2013;Peri et al, 2017) that have been associated to the rejuvenation of the bedrock basement. These old structures have influenced the evolution, kinematics and segmentation of the El Tigre fault (Fazzito et al 2013(Fazzito et al , 2016, which provides one significant example of Pliocene-Quaternary activity (Bastías and Bastías 1987;Cortés et al 1999;INPRES, 1982;Siame et al, 1997aSiame et al, , b, 2006 at the western margin of Precordillera. Siame et al (2006) suggested that at 30° S both the Calingasta-Iglesia Valley and the Precordillera fold-and-thrust belt can be interpreted as a part of a crustal-scale transpressive zone, whose dextral strike-slip component is occurred mainly along the El Tigre Fault zone.…”

“…Morphotectonic features reveal the Quaternary activity of this fault zone (fault scarps, releasing basins, pressure ridges and offset streams) and disruptions of Plei stocene surfaces (Siame et al 1997a, b;Fazzito et al, 2013; Figure 2). The Pliocene-Quaternary activity of the El Tigre fault has been inferred by direct observation of the main and associated structures in trenches (Bastías et al, 1984;Bastías, 1985;INPRES, 1982;Siame, 1998), by indirect observation along ERTs (Figure 2; Fazzito et al, 2013), by paleomagnetic studies (Fazzito et al, 2016), and by detailed slip-rates estimations (Siame et al, 1997a, b). All this evidence suggested that the El Tigre fault was originated at Pliocene times (Fazzito et al, 2016) and was reactivated and evolved during the Pleistocene (Fazzito et al, 2013;Siame et al, 1997a, b).…”

“…The Pliocene-Quaternary activity of the El Tigre fault has been inferred by direct observation of the main and associated structures in trenches (Bastías et al, 1984;Bastías, 1985;INPRES, 1982;Siame, 1998), by indirect observation along ERTs (Figure 2; Fazzito et al, 2013), by paleomagnetic studies (Fazzito et al, 2016), and by detailed slip-rates estimations (Siame et al, 1997a, b). All this evidence suggested that the El Tigre fault was originated at Pliocene times (Fazzito et al, 2016) and was reactivated and evolved during the Pleistocene (Fazzito et al, 2013;Siame et al, 1997a, b). Based upon geometrical variations along its strike, the El Tigre fault was divided into three major segments: the northern, central and southern segments J o u r n a l P r e -p r o o f (Figure 2a; Siame et al 1997b, Fazzito et al 2013).…”