Crustal Provenance and Cooling of the Basement Complexes of the Sierra de San Luis: An Insight Into the Tectonic History of the Pro to-Andean Margin of Gondwana

Steenken, André; Werner, K.; Luch, Mónica G. Lopez de; Siegesmund, Siegfried; Pawlig, Sabine

doi:10.1016/s1342-937x(05)71092-3

Cited by 64 publications

(103 citation statements)

References 51 publications

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“…Ramos 1988Ramos , 2009Ramos et al 2002;Steenken et al 2004;Miller and Söllner 2005). Potential sutures indicating the margins of adjacent terranes, e.g.…”

Section: Regional Setting and Geodynamic Evolutionmentioning

confidence: 99%

Exhumation and uplift of the Sierras Pampeanas: preliminary implications from K–Ar fault gouge dating and low-T thermochronology in the Sierra de Comechingones (Argentina)

Löbens

Bense

Wemmer

et al. 2010

Int J Earth Sci (Geol Rundsch)

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The Sierras Pampeanas in central and northwestern Argentina constitute a distinct morphotectonic feature between 27°S and 33°S. The last stage of uplift and deformation in this area are interpreted to be closely related to the Andean flat-slab subduction of the Nazca plate beneath the South American plate. K-Ar fault gouge dating and low-temperature thermochronology along two transects within the Sierra de Comechingones reveal a minimum age for the onset of brittle deformation about 340 Ma, very low exhumation rates since Late Paleozoic time, as well as a total exhumation of about 2.3 km since the Late Cretaceous. New Ar-Ar ages (7.54-1.91 Ma) of volcanic rocks from the San Luis volcanic belt support the eastward propagation of the flat-slab magmatic front, confirming the onset of flat-slab related deformation in this region at 11.2 Ma. Although low-temperature thermochronology does not clearly constrain the signal of the Andean uplift, it is understood that the current structural relief related to the Comechingones range has been achieved after the exhumation of both fault walls (circa 80-70 Ma).

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“…Ramos 1988Ramos , 2009Ramos et al 2002;Steenken et al 2004;Miller and Söllner 2005). Potential sutures indicating the margins of adjacent terranes, e.g.…”

Section: Regional Setting and Geodynamic Evolutionmentioning

confidence: 99%

Exhumation and uplift of the Sierras Pampeanas: preliminary implications from K–Ar fault gouge dating and low-T thermochronology in the Sierra de Comechingones (Argentina)

Löbens

Bense

Wemmer

et al. 2010

Int J Earth Sci (Geol Rundsch)

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“…Geological studies of the Sierra de San Luis have traditionally been focused on the tectonometamorphic evolution of the crystalline basement, which is considered to be completed by Early Carboniferous times (Criado Roque et al, 1981;Ortiz Suárez et al, 1992;Von Gosen, 1998;Steenken et al, 2004). Deformation of the basement was dominated by brittle deformation ever since, leading to characteristic N-S trending fault blocks bounded by major reverse faults during Cenozoic crustal shortening (Fig.…”

Section: Geological and Morphotectonic Settingmentioning

confidence: 99%

“…This basement was formed by accretion of multiple terranes during several orogenic cycles (i.e., Pampean, Famatinian and Achalian Orogeny) between the late Proterozoic and early Paleozoic (e.g., Ramos, 1988;Sims et al, 1998;Ramos et al, 2002;Steenken et al, 2004Steenken et al, , 2010Miller and Söllner, 2005;Ramos, 2008).…”

Section: Geological and Morphotectonic Settingmentioning

confidence: 99%

Exhumation history and landscape evolution of the Sierra de San Luis (Sierras Pampeanas, Argentina) - new insights from low - temperature thermochronological data

Bense

Costa

Oriolo

et al. 2017

andgeo

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ABSTRACT. This paper presents low-temperature thermochronological data and K-Ar fault gouge ages from the Sierra de San Luis in the Eastern Sierras Pampeanas in order to constrain its low-temperature thermal evolution and exhumation history. Thermal modelling based on (U-Th)/He dating of apatite and zircon and apatite fission track dating point to the Middle Permian and the Triassic/Early Jurassic as main cooling/exhumation phases, equivalent to ca. 40-50% of the total exhumation recorded by the applied methods. Cooling rates are generally low to moderate, varying between 2-10 °C/Ma during the Permian and Triassic periods and 0.5-1.5 °C/Ma in post-Triassic times. Slow cooling and, thus, persistent residence of samples in partial retention/partial annealing temperature conditions strongly influenced obtained ages. Thermochronological data indicate no significant exhumation after Cretaceous times, suggesting that sampled rocks were already at or near surface by the Cretaceous or even before. As consequence, Cenozoic cooling rates are low, generally between 0.2-0.5 °C/Ma which is, depending on geothermal gradient used for calculation, equivalent to a total Cenozoic exhumation of 0.6-1.8 km. K-Ar fault gouge data reveal long-term brittle fault activity. Fault gouge ages constrain the end of ductile and onset of brittle deformation in the Sierra de San Luis to the Late Carboniferous/Early Permian. Youngest K-Ar illite ages of 222-172 Ma are interpreted to represent the last illite formation event, although fault activity is recorded up to the Holocene. RESUMEN. Historia de la exhumación y evolución del paisaje de la sierra de San Luis (Sierras Pampeanas, Argentina)-nuevas perspectivas a partir de datos termocronológicos de baja temperatura. Esta contribución presenta datos de termocronología de baja temperatura y edades de illitas generadas en zonas de fallas de la sierra de San Luis, en las Sierras Pampeanas Orientales de Argentina, con el propósito de aportar al conocimiento de la historia de su exhumación y evolución termal de baja temperatura. El modelado termal basado en dataciones de (U-Th)/He, apatita, circón y trazas de fisión sugiere que las principales fases de exhumación y enfriamiento ocurrieron durante el Pérmico medio y Triásico/Jurásico inferior, contribuyendo con aproximadamente 40-50% de la exhumación total registrada por los métodos utilizados. Las tasas de enfriamiento son, en general, bajas a moderadas, variando entre 2-10 °C/Ma durante el Pérmico y Triásico y 0,5-1,5 °C/Ma después del este último período. El lento enfriamiento y la persistente residencia de las muestras analizadas en condiciones térmicas de retención parcial (partial annealing) ha influenciado notoriamente las edades obtenidas. Los datos termocronológicos indican que no ha habido una exhumación 276 Exhumation history and LandscapE EvoLution of thE siErra dE san Luis (siErras pampEanas, argEntina)... significativa después del Cretácico o incluso antes. Consecuentemente, las tasas de enfriamiento durante el Cenozoico, son bajas, ge...

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“…La zona de estudio forma parte de la unidad morfoestructural de Sierras Pampeanas desarrollada por la acreción de diferentes terrenos alóctonos y parautóctonos (Terreno Pampia, Rapela et al, 1998;Terreno Cuyania, Ramos, 1995;Ramos et al, 1998;Vujovich et al, 2004) durante el Proterozoico tardío y el Paleozoico temprano, amalgamados contra el protomargen de Gondwana (Astini y Thomas, 1999;Ramos et al, 2002;Ramos, 2010;Steenken et al, 2004;Miller y Söllner, 2005). Las Sierras Pampeanas Occidentales, en el sector de las SVF-LH, se caracterizan por un basamento compuesto por metamorfitas y migmatitas con una edad de metamorfismo ordovícica que alojan una serie de cuerpos intrusivos correspondientes a un arco magmático que se desarrolló durante la Orogenia Famatiniana entre el Ordovícico temprano y el Ordovícico medio (490 -460 Ma, Tibaldi et al, 2009 y referencias allí insertadas).…”

Section: Arco Geológicounclassified

Modelo petrofísico del borde oriental de las sierras de Valle Fértil- La Huerta, Argentina a partir de datos sísmicos y petrológicos

et al. 2017

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This paper is a contribution to the knowledge of the crustal structure of the eastern flank of the Valle Fértil - La Huerta ranges (Western Sierras Pampeanas, San Juan, Argentina) at 31°S, in the Andean foreland region, where the Nazca plate is subducting horizontally at about 100 km depth. A 1D velocity model was constrained, combining petrographic and seismological observations from analysis of 19 igneous and metaigneous plutonic rocks belonging to the Famatinian (Ordovician) magmatic arc, which make up most of the crystalline basement of these ranges. Granitoid lithologies predominate in the northern region whereas mafic lithologies are more common to the south. The seismological analysis consisted of modeling teleseismic receiver functions near three seismological stations: LUNA, MAJA and CHUC, in places where those rocks are dominant. Thus, P and S seismic-wave velocities (Vp and Vs) and Poisson´s coefficient (ν), among other elastic parameters, were obtained. The seismic velocity model indicates an overthickened crust with an average thickness between 55 and 60 km, which matches with global average values (~41km); this agrees well with the hypothesis of partial eclogitization in the lower crust. The presence of two seismic velocity discontinuities at mid-crustal levels (12 and 28 km depths), likely associated to décollements, might be related to the accretion of the Cuyania terrane to the Pampia terrane. We obtained low P seismic-wave velocities (Vp ~5.8 km/s), Vp/Vs ratio (~1.70) in upper crust levels consistent with granitoid lithologies, as well as high P seismic-wave velocities (Vp ~6.76 km/s), Vp/Vs ratio (~1.78) in lower crust levels; these figures match with mafic lithologies of a more dense (~3.00 g/cm3), lower crust with respect to other back-arc Andean regions. Also, these values are consistent with the existence of mafic rocks composed of olivine, ortho- and clinopyroxene, which constitute the root of the Famatinian magmatic arc. These results indicate high-grade metamorphic conditions and depths corresponding to geophysical properties of middle to lower crust and correlate with the hypothesis of a dehydrated, cool and magnesium-enriched mantle located in the region between the subducted Nazca slab and the bottom of the Cuyania terrain crust.

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Crustal Provenance and Cooling of the Basement Complexes of the Sierra de San Luis: An Insight Into the Tectonic History of the Pro to-Andean Margin of Gondwana

Cited by 64 publications

References 51 publications

Exhumation and uplift of the Sierras Pampeanas: preliminary implications from K–Ar fault gouge dating and low-T thermochronology in the Sierra de Comechingones (Argentina)

Exhumation and uplift of the Sierras Pampeanas: preliminary implications from K–Ar fault gouge dating and low-T thermochronology in the Sierra de Comechingones (Argentina)

Exhumation history and landscape evolution of the Sierra de San Luis (Sierras Pampeanas, Argentina) - new insights from low - temperature thermochronological data

Modelo petrofísico del borde oriental de las sierras de Valle Fértil- La Huerta, Argentina a partir de datos sísmicos y petrológicos

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