Does the topographic distribution of the central Andean Puna Plateau result from climatic or geodynamic processes?

Abstract

Orogenic plateaus are extensive, high-elevation areas with low internal relief that have been attributed to deep-seated and/or climate-driven surface processes. In the latter case, models predict that lateral plateau growth results from increasing aridity along the margins as range uplift shields the orogen interior from precipitation. We analyze the spatiotemporal progression of basin isolation and fi lling at the eastern margin of the Puna Plateau of the Argentine Andes to determine if the topography predicted by such models is observed. We fi nd that the timing of basin fi lling and reexcavation is variable, suggesting nonsystematic plateau growth. Instead, the Airy isostatically compensated component of topography constitutes the majority of the mean elevation gain between the foreland and the plateau. This indicates that deep-seated phenomena, such as changes in crustal thickness and/or lateral density, are required to produce high plateau elevations. In contrast, the frequency of the uncompensated topography within the plateau and in the adjacent foreland that is interrupted by ranges appears similar, although the amplitude of this topographic component increases east of the plateau. Combined with sedimentologic observations, we infer that the low internal relief of the plateau likely results from increased aridity and sediment storage within the plateau and along its eastern margin.

Structural, Geomorphic, and Depositional Characteristics of Contiguous and Broken Foreland Basins: Examples from the Eastern Flanks of the Central Andes in Bolivia and NW Argentina

“…This leads to the aridification of the headwaters of basins in the lee of the rising topographic barrier. This may conspire to cause a transient Strecker et al, 2009) or permanent (Alonso et al, 1991;Vandervoort et al, 1995;Horton et al, 2002) decrease in erosional power of the rivers draining these basins, reducing the likelihood of fluvial connection with the foreland. Fig.…”

“…The discontinuous nature of deformation within northwestern Argentina has produced spatially disparate and diachronous storage of sediments upstream of the uplifting ranges (Bossi and Palma, 1982;Strecker et al, 1989Strecker et al, , 2009Carrapa et al, 2009). Within basins flanking the margins of the Puna Plateau, conglomerates sourced from the Puna margin and ranges surrounding these basins are sometimes intercalated with lacustrine sediments as well as tephras that constrain the timing of deposition of these sediments.…”

“…This mode of foreland basin evolution eventually compartmentalizes a formerly contiguous sedimentary basin and often causes trends in rock uplift and sedimentation patterns that are not predicted by standard foreland basin models (e.g., Jordan and Allmendinger, 1986). This accommodation of deformation within basement ranges and the formation of a broken foreland may occur well inboard of the primary topographic margin of the orogen (e.g., Ramos et al, 2002;Strecker et al, 2009;Iaffa et al, 2011). Importantly, the uplift of such basement ranges leads to a different flexural response than the one expected in typical foreland basin systems related to a growing orogenic wedge.…”

Genetic framework of Neogene–Quaternary basin closure process in central Turkey

“…Whereas some of the works indicate a major role of external forces (such as climate and/or surface processes; e.g., Heller et al, 2011) in initiating basin closure, some others suggest that the role of internal forces (such as isostasy and/ or tectonics; e.g., Isacks, 1988) is much stronger. In other settings, there is an apparent coupling between internal and external forces (e.g., Masek et al, 1994;Garcia-Castellanos, 2006;Strecker et al, 2009). In every case, closed basins form when the rates of sediment supply derived from the surrounding mountains is less than the rate of accommodation by tectonics in the basin (e.g., Carroll and Bohacs, 1999;Garcia-Castellanos, 2007;Heller et al, 2011).…”

Middle to late Miocene extensional collapse of the North Patagonian Andes (41°30′–42°S)

“…Then, as a first approach, we propose that these along-strike differences in topography could be the result of a complex spatio-temporal pattern of structural evolution of the Ñirihuau fold and thrust belt, as recently described in other parts of the Andes (see for example Strecker et al, 2007Strecker et al, , 2009Giambiagi et al, 2009;Hain et al, 2011;Parra et al, 2012;Pearson et al, 2012). These disparate spatio-temporal patterns of deformation strongly control sediment dynamics and consequently erosional processes, which in turn can influence the evolution of the thrust wedge (Berger et al, 2008;Whipple, 2009, and references therein).…”