@article{ForteWhippleBookhagenetal.2016,
  author    = {Forte, Adam M. and Whipple, Kelin X. and Bookhagen, Bodo and Rossi, Matthew W.},
  title     = {Decoupling of modern shortening rates, climate, and topography in the Caucasus},
  series = {Earth \& planetary science letters},
  volume    = {449},
  journal   = {Earth \& planetary science letters},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0012-821X},
  doi       = {10.1016/j.epsl.2016.06.013},
  pages     = {282 -- 294},
  year      = {2016},
  abstract  = {The Greater and Lesser Caucasus mountains and their associated foreland basins contain similar rock types, experience a similar two-fold, along-strike variation in mean annual precipitation, and were affected by extreme base-level drops of the neighboring Caspian Sea. However, the two Caucasus ranges are characterized by decidedly different tectonic regimes and rates of deformation that are subject to moderate (less than an order of magnitude) gradients in climate, and thus allow for a unique opportunity to isolate the effects of climate and tectonics in the evolution of topography within active orogens. There is an apparent disconnect between modern climate, shortening rates, and topography of both the Greater Caucasus and Lesser Caucasus which exhibit remarkably similar topography along-strike despite the gradients in forcing. By combining multiple datasets, we examine plausible causes for this disconnect by presenting a detailed analysis of the topography of both ranges utilizing established relationships between catchment-mean erosion rates and topography (local relief, hillslope gradients, and channel steepness) and combining it with a synthesis of previously published low-temperature thermochronologic data. Modern climate of the Caucasus region is assessed through an analysis of remotely-sensed data (TRMM and MODIS) and historical streamflow data. Because along-strike variation in either erosional efficiency or thickness of accreted material fail to explain our observations, we suggest that the topography of both the western Lesser and Greater Caucasus are partially supported by different geodynamic forces. In the western Lesser Caucasus, high relief portions of the landscape likely reflect uplift related to ongoing mantle lithosphere delamination beneath the neighboring East Anatolian Plateau. In the Greater Caucasus, maintenance of high topography in the western portion of the range despite extremely low (<2-4 mm/y) modern convergence rates may be related to dynamic topography from detachment of the north-directed Greater Caucasus slab or to a recent slowing of convergence rates. Large-scale spatial gradients in climate are not reflected in the topography of the Caucasus and do not seem to exert any significant control on the tectonics or structure of either range. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{BallatoLandgrafSchildgenetal.2015,
  author    = {Ballato, Paolo and Landgraf, Angela and Schildgen, Taylor F. and Stockli, Daniel F. and Fox, Matthew and Ghassemi, Mohammad R. and Kirby, Eric and Strecker, Manfred},
  title     = {The growth of a mountain belt forced by base-level fall: Tectonics and surface processes during the evolution of the Alborz Mountains, N Iran},
  series = {Earth \& planetary science letters},
  volume    = {425},
  journal   = {Earth \& planetary science letters},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0012-821X},
  doi       = {10.1016/j.epsl.2015.05.051},
  pages     = {204 -- 218},
  year      = {2015},
  abstract  = {The idea that climatically modulated erosion may impact orogenic processes has challenged geoscientists for decades. Although modeling studies and physical calculations have provided a solid theoretical basis supporting this interaction, to date, field-based work has produced inconclusive results. The central-western Alborz Mountains in the northern sectors of the Arabia-Eurasia collision zone constitute a promising area to explore these potential feedbacks. This region is characterized by asymmetric precipitation superimposed on an orogen with a history of spatiotemporal changes in exhumation rates, deformation patterns, and prolonged, km-scale base-level changes. Our analysis suggests that despite the existence of a strong climatic gradient at least since 17.5 Ma, the early orogenic evolution (from similar to 36 to 9-6 Ma) was characterized by decoupled orographic precipitation and tectonics. In particular, faster exhumation and sedimentation along the more arid southern orogenic flank point to a north-directed accretionary flux and underthrusting of Central Iran. Conversely, from 6 to 3 Ma, erosion rates along the northern orogenic flank became higher than those in the south, where they dropped to minimum values. This change occurred during a similar to 3-Myr-long, km-scale base-level lowering event in the Caspian Sea. We speculate that mass redistribution processes along the northern flank of the Alborz and presumably across all mountain belts adjacent to the South Caspian Basin and more stable areas of the Eurasian plate increased the sediment load in the basin and ultimately led to the underthrusting of the Caspian Basin beneath the Alborz Mountains. This underthrusting in turn triggered a new phase of northward orogenic expansion, transformed the wetter northern flank into a new pro-wedge, and led to the establishment of apparent steady-state conditions along the northern orogenic flank (i.e., rock uplift equal to erosion rates). Conversely, the southern mountain front became the retro-wedge and experienced limited tectonic activity. These observations overall raise the possibility that mass-distribution processes during a pronounced erosion phase driven by base-level changes may have contributed to the inferred regional plate-tectonic reorganization of the northern Arabia-Eurasia collision during the last similar to 5 Ma. (C) 2015 Elsevier B.V. All rights reserved.},
  language  = {en}
}