Uplift of the Central Andes of NW Argentina associated with upper crustal shortening, revealed by multiproxy isotopic analyses

Abstract

This study contributes to the uplift history of the Andes, which has received increasing attention in recent years because of its implications for geodynamic models and climate feedbacks. Shortening resulting in crustal thickening and removal of gravitationally unstable mantle lithosphere has been proposed to control deformation and uplift of Cordillera-type orogenic systems such as the Puna Plateau of the central Andes and its eastern margin, the Eastern Cordillera. We present new clumped isotope (Δ 47 ), δ 18 O, and δ 2 Η data from carbonate nodules, marlstone, spring deposits, and volcanic ashes from the Puna Plateau and Eastern Cordillera of NW Argentina. When combined with other geological evidence, our data indicate that the Puna Plateau was near its present elevation since at least~10 Ma, whereas the Eastern Cordillera rosẽ 1.5 km between~14 and~7 Ma. This history of uplift correlates with active shortening in the Eastern Cordillera and with incorporation of a regional foreland into the propagating orogenic wedge. Our study suggests that the elevation of the Puna Plateau changed little during the Miocene-Pliocene, whereas the margin experienced significant uplift associated with active deformation and crustal thickening.

Ecological and hydroclimate responses to strengthening of the Hadley circulation in South America during the Late Miocene cooling

“…We selected records from sedimentary basins ( Fig. 1) that achieved elevations and topography similar to modern largely before the LMC (29)(30)(31). Local topography was formed at different times due to the different tectono-morphic setting of the basins considered in this study ( Fig.…”

Can stable isotopes ride out the storms? The role of convection for water isotopes in models, records, and paleoaltimetry studies in the central Andes

“…Each of these materials retains the δ 18 O or δD composition of ancient meteoric waters (e.g. Lee-Thorpe and Van der Merwe, 1987;Cerling et al, 1993;Garzione et al, 2008;Mulch et al, 2008;Sachse et al, 2012). Especially for materials that capture shortterm variations in the isotopic composition of rainfall, the absence of systematic stable isotope-elevation relationships may render any paleoaltimetry interpretation complex, if not impossible (Blisniuk and Stern, 2005).…”

“…Dansgaard, 1964;Gonfiantini et al, 2001;Bowen and Wilkinson, 2002;Cerling et al, 1993;Dettman et al, 2003;Garzione et al, 2008;Mix et al, 2013). Despite the plethora of applications of these isotopes as proxies for earth surface and atmospheric processes, there is still a lack of understanding of the * Corresponding author.…”

Analytical effects on clumped isotope thermometry: Comparison of a common sample set analyzed using multiple instruments, types of standards, and standardization windows

“…The measurement of the organization of multiple rare isotopes within a molecule opens up avenues of scientific inquiry that are not accessible with single isotope systems, such as the long‐standing problem of determining the respective influences of water isotopic values and carbonate growth temperatures on the oxygen isotope composition of carbonate minerals. The carbonate clumped isotope thermometer has been deployed in a growing number of applications, such as paleoclimatology, sedimentology and basin analysis, and tectonics because it is completely independent of the sample's bulk isotopic composition and allows temperatures to be measured directly without knowledge of the isotopic composition of water. In this application, the overexpression of 13 C‐ 18 O bonds within the carbonate lattice relative to a randomized mixture of isotopes (denoted Δ 47 ) is controlled by the formation temperature of the carbonate mineral, assuming that it formed at equilibrium …”