TY - JOUR A1 - Schildgen, Taylor F. A1 - Cosentino, D. A1 - Bookhagen, Bodo A1 - Niedermann, Samuel A1 - Yildirim, C. A1 - Echtler, Helmut Peter A1 - Wittmann, Hella A1 - Strecker, Manfred T1 - Multi-phased uplift of the southern margin of the Central Anatolian plateau, Turkey a record of tectonic and upper mantle processes JF - Earth & planetary science letters N2 - Uplifted Neogene marine sediments and Quaternary fluvial terraces in the Mut Basin, southern Turkey, reveal a detailed history of surface uplift along the southern margin of the Central Anatolian plateau from the Late Miocene to the present. New surface exposure ages (Be-10, Al-26, and Ne-21) of gravels capping fluvial strath terraces located between 28 and 135 m above the Goksu River in the Mut Basin yield ages ranging from ca. 25 to 130 ka, corresponding to an average incision rate of 0.52 to 0.67 mm/yr. Published biostratigraphic data combined with new interpretations of the fossil assemblages from uplifted marine sediments reveal average uplift rates of 0.25 to 0.37 mm/yr since Late Miocene time (starting between 8 and 5.45 Ma), and 0.72 to 0.74 mm/yr after 1.66 to 1.62 Ma. Together with the terrace abandonment ages, the data imply 0.6 to 0.7 mm/yr uplift rates from 1.6 Ma to the present. The different post-Late Miocene and post-1.6 Ma uplift rates can imply increasing uplift rates through time, or multi-phased uplift with slow uplift or subsidence in between. Longitudinal profiles of rivers in the upper catchment of the Mut and Ermenek basins show no apparent lithologic or fault control on some knickpoints that occur at 1.2 to 1.5 km elevation, implying a transient response to a change in uplift rates. Projections of graded upper relict channel segments to the modern outlet, together with constraints from uplifted marine sediments, show that a slower incision/uplift rate of 0.1 to 0.2 mm/yr preceded the 0.7 mm/yr uplift rate. The river morphology and profile projections therefore reflect multi-phased uplift of the plateau margin, rather than steadily increasing uplift rates. Multi-phased uplift can be explained by lithospheric slab break-off and possibly also the arrival of the Eratosthenes Seamount at the collision zone south of Cyprus. KW - Central Anatolian plateau KW - uplift KW - fluvial strath terraces KW - cosmogenic nuclides KW - biostratigraphy KW - channel projection Y1 - 2012 U6 - https://doi.org/10.1016/j.epsl.2011.12.003 SN - 0012-821X VL - 317 SP - 85 EP - 95 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kober, Florian A1 - Zeilinger, Gerold A1 - Hippe, Kristina A1 - Marc, Odin A1 - Lendzioch, Theodora A1 - Grischott, Reto A1 - Christl, Marcus A1 - Kubik, Peter W. A1 - Zola, Ramiro T1 - Tectonic and lithological controls on denudation rates in the central Bolivian Andes JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - The topographic signature of a mountain belt depends on the interplay of tectonic, climatic and erosional processes, whose relative importance changes over times, while quantifying these processes and their rates at specific times remains a challenge. The eastern Andes of central Bolivia offer a natural laboratory in which such interplay has been debated. Here, we investigate the Rio Grande catchment which crosses orthogonally the eastern Andes orogen from the Eastern Cordillera into the Subandean Zone, exhibiting a catchment relief of up to 5000 m. Despite an enhanced tectonic activity in the Subandes, local relief, mean and modal slopes and channel steepness indices are largely similar compared to the Eastern Cordillera and the intervening Interandean Zone. Nevertheless, a dataset of 57 new cosmogenic 10Be and 26AI catchment wide denudation rates from the Rio Grande catchment reveals up to one order of magnitude higher denudation rates in the Subandean Zone (mean 0.8 mm/yr) compared to the upstream physiographic regions. We infer that tectonic activity in the thrusting dominated Subandean belt causes higher denudation rates based on cumulative rock uplift investigations and due to the absence of a pronounced climate gradient. Furthermore, the lower rock strength of the Subandean sedimentary units correlates with mean slopes similar to the ones of the Eastern Cordillera and Interandean Zone, highlighting the fact, that lithology and rock strength can control high denudation rates at low slopes. Low denudation rates measured at the outlet of the Rio Grande catchment (Abapo) are interpreted to be a result of a biased cosmogenic nuclide mixing that is dominated by headwater signals from the Eastern Cordillera and the Interandean zone and limited catchment sediment connectivity in the lower river reaches. Therefore, comparisons of short- (i.e., sediment yield) and millennial denudation rates require caution when postulating tectonic and/or climatic forcing without detailed studies. (C) 2015 The Authors. Published by Elsevier B.V. KW - Rio Grande KW - seismicity KW - uplift KW - rock strength KW - cosmogenic nuclides KW - denudation Y1 - 2015 U6 - https://doi.org/10.1016/j.tecto.2015.06.037 SN - 0040-1951 SN - 1879-3266 VL - 657 SP - 230 EP - 244 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wichura, Henry A1 - Jacobs, Louis L. A1 - Lin, Andrew A1 - Polcyn, Michael J. A1 - Manthi, Fredrick K. A1 - Winkler, Dale A. A1 - Strecker, Manfred A1 - Clemens, Matthew T1 - A 17-My-old whale constrains onset of uplift and climate change in east Africa JF - Proceedings of the National Academy of Sciences of the United States of America N2 - Timing and magnitude of surface uplift are key to understanding the impact of crustal deformation and topographic growth on atmospheric circulation, environmental conditions, and surface processes. Uplift of the East African Plateau is linked to mantle processes, but paleoaltimetry data are too scarce to constrain plateau evolution and subsequent vertical motions associated with rifting. Here, we assess the paleotopographic implications of a beaked whale fossil (Ziphiidae) from the Turkana region of Kenya found 740 km inland from the present-day coastline of the Indian Ocean at an elevation of 620 m. The specimen is similar to 17 My old and represents the oldest derived beaked whale known, consistent with molecular estimates of the emergence of modern straptoothed whales (Mesoplodon). The whale traveled from the Indian Ocean inland along an eastward-directed drainage system controlled by the Cretaceous Anza Graben and was stranded slightly above sea level. Surface uplift from near sea level coincides with paleoclimatic change from a humid environment to highly variable and much drier conditions, which altered biotic communities and drove evolution in east Africa, including that of primates. KW - east Africa KW - Ziphiidae KW - uplift KW - drainage KW - paleoenvironment Y1 - 2015 U6 - https://doi.org/10.1073/pnas.1421502112 SN - 0027-8424 VL - 112 IS - 13 SP - 3910 EP - 3915 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Hansman, Reuben J. A1 - Ring, Uwe A1 - Thomson, Stuart N. A1 - den Brok, Bas A1 - Stuebner, Konstanze T1 - Late Eocene Uplift of the Al Hajar Mountains, Oman, Supported by Stratigraphy and Low-Temperature Thermochronology JF - Tectonics N2 - Uplift of the Al Hajar Mountains in Oman has been related to either Late Cretaceous ophiolite obduction or the Neogene Zagros collision. To test these hypotheses, the cooling of the central Al Hajar Mountains is constrained by 10 apatite (U-Th)/He (AHe), 15 fission track (AFT), and four zircon (U-Th)/He (ZHe) sample ages. These data show differential cooling between the two major structural culminations of the mountains. In the 3km high Jabal Akhdar culmination AHe single-grain ages range between 392 Ma and 101 Ma (2 sigma errors), AFT ages range from 518 Ma to 324 Ma, and ZHe single-grain ages range from 62 +/- 3Ma to 39 +/- 2 Ma. In the 2 km high Saih Hatat culmination AHe ages range from 26 +/- 4 to 12 +/- 4 Ma, AFT ages from 73 +/- 19Ma to 57 +/- 8 Ma, and ZHe single-grain ages from 81 +/- 4 Ma to 58 +/- 3 Ma. Thermal modeling demonstrates that cooling associated with uplift and erosion initiated at 40 Ma, indicating that uplift occurred 30 Myr after ophiolite obduction and at least 10 Myr before the Zagros collision. Therefore, this uplift cannot be related to either event. We propose that crustal thickening supporting the topography of the Al Hajar Mountains was caused by a slowdown of Makran subduction and that north Oman took up the residual fraction of N-S convergence between Arabia and Eurasia. KW - thermochronology KW - Oman KW - uplift KW - mountains KW - fission-track KW - (U-Th) KW - He Y1 - 2017 U6 - https://doi.org/10.1002/2017TC004672 SN - 0278-7407 SN - 1944-9194 VL - 36 SP - 3081 EP - 3109 PB - American Geophysical Union CY - Washington ER -