@article{ScharfSudoPracejusetal.2020,
  author    = {Scharf, Andreas and Sudo, Masafumi and Pracejus, Bernhard and Mattern, Frank and Callegari, Ivan and Bauer, Wilfried and Scharf, Katharina},
  title     = {Late Lutetian (Eocene) mafic intrusion into shallow marine platform deposits north of the Oman Mountains (Rusayl Embayment) and its tectonic significance},
  series = {Journal of African earth sciences},
  volume    = {170},
  journal   = {Journal of African earth sciences},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1464-343X},
  doi       = {10.1016/j.jafrearsci.2020.103941},
  pages     = {15},
  year      = {2020},
  abstract  = {A silica undersaturated alkali-olivine basanitic magma intruded the late Paleocene/early Eocene Jafnayn Formation near Muscat. Geochemical analyses indicate that a significant amount of host rock (limestone) was assimilated into the magma. We dated the basanite as 42.7 +/- 1.0 Ma (2 sigma error; late Lutetian), using the whole rock Ar-40/Ar-39 step-wise heating technique. Intrusion occurred in the hanging wall of a major regional extensional shear zone (Frontal Range Fault, FRF) bounding the northern margin of two domes within the Oman Mountains (Jabal Akhdar and Saih Hatat domes). Two shear intervals along the FRF have been documented. The first interval lasted immediately after emplacement of the Semail Ophiolite (latest Cretaceous-early Eocene) while the second and poorly constrained interval was assumed to have occurred during the Oligocene. The proximity of the basanite to the FRF suggests that magma used extensional faults for the upper part of its ascent path. Reactivated Permian rift faults of the Pangaea rift or other preexisting faults may have been used for the lower ascent part. We conclude that the basanite intrusion coincided with the onset of the second deformation interval along the FRF, because (1) the position of the basanite is near a dextral releasing bend, associated with the second shear interval, (2) the overlap of our Ar-40/Ar-39 age with the cooling curves for rocks from the nearby Jabal Akhdar Dome, and (3) the basanite postdates the first FRF deformation episode by > 10 Ma. Thus, the second interval along the FRF had started already during the late Lutetian and probably lasted into the Miocene.},
  language  = {en}
}
@article{LunaBookhagenNiedermannetal.2018,
  author    = {Luna, Lisa Victoria and Bookhagen, Bodo and Niedermann, Samuel and Rugel, Georg and Scharf, Andreas and Merchel, Silke},
  title     = {Glacial chronology and production rate cross-calibration of five cosmogenic nuclide and mineral systems from the southern Central Andean Plateau},
  series = {Earth \& planetary science letters},
  volume    = {500},
  journal   = {Earth \& planetary science letters},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0012-821X},
  doi       = {10.1016/j.epsl.2018.07.034},
  pages     = {242 -- 253},
  year      = {2018},
  abstract  = {Glacial deposits on the high-altitude, arid southern Central Andean Plateau (CAP), the Puna in northwestern Argentina, document past changes in climate, but the associated geomorphic features have rarely been directly dated. This study provides direct age control of glacial moraine deposits from the central Puna (24 degrees S) at elevations of 3900-5000 m through surface exposure dating with cosmogenic nuclides. Our results show that the most extensive glaciations occurred before 95 ka and an additional major advance occurred between 46 and 39 ka. The latter period is synchronous with the highest lake levels in the nearby Pozuelos basin and the Minchin (Inca Huasi) wet phase on the Altiplano in the northern CAP. None of the dated moraines produced boulder ages corresponding to the Tauca wet phase (24-15 ka). Additionally, the volcanic lithologies of the deposits allow us to establish production ratios at low latitude and high elevation for five different nuclide and mineral systems: Be-10, Ne-21, and Al-26 from quartz (11 or 12 samples) and He-3 and Ne-21 from pyroxene (10 samples). We present production ratios for all combinations of the measured nuclides and cross-calibrated production rates for 21Ne in pyroxene and quartz for the high, (sub-)tropical Andes. The production rates are based on our Be-10-normalized production ratios and a weighted mean of reference 10Be production rates calibrated in the high, tropical Andes (4.02 +/- 0.12 at g(-1) yr(-1)). These are, Ne-21(qtz): 18.1 +/- 1.2 at g(-1) yr(-1) and Ne-21(px): 36.6 +/- 1.8 at g(-1) yr(-1) (En(88-94)) scaled to sea level and high latitude using the Lal/Stone scheme, with 1 sigma uncertainties. As He-3 and Al-26 have been directly calibrated in the tropical Andes, we recommend using those rates. Finally, we compare exposure ages calculated using all measured cosmogenic nuclides from each sample, including 11 feldspar samples measured for Cl-36, and a suite of previously published production rates. (C) 2018 Published by Elsevier B.V.},
  language  = {en}
}
@article{ScharfHandySchmidetal.2016,
  author    = {Scharf, Andreas and Handy, Mark R. and Schmid, Stefan M. and Favaro, Silvia and Sudo, Masafumi and Schuster, Ralf and Hammerschmidt, Konrad},
  title     = {Grain-size effects on the closure temperature of white mica in a crustal-scale extensional shear - zone - Implications of in-situ Ar-40/Ar-39 laser-ablation of white mica for dating shearing and cooling (Tauern Window, Eastern Alps)},
  series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  volume    = {674},
  journal   = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0040-1951},
  doi       = {10.1016/j.tecto.2016.02.014},
  pages     = {210 -- 226},
  year      = {2016},
  abstract  = {In-situ Ar-40/Ar-39 laser ablation dating of white-mica grains was performed on samples from the footwall of a crustal-scale extensional fault (Katschberg Normal Fault; KNF) that accommodated eastward orogen-parallel displacement of Alpine orogenic crust in the eastern part of the Tauern Window. This dating yields predominantly cooling ages ranging from 31 to 13 Myr, with most ages clustering between 21 and 17 Myr. Folded white micas that predate the main Katschberg foliation yield, within error, the same ages as white-mica grains that overgrow this foliation. However, the absolute ages of both generations are older at the base (20 Myr) where their grain size is larger (300-500 mu m), than at the top and adjacent to the hangingwall (17 Myr) of this shear zone where grain size is smaller (<100-300 mu m). This fining-upward trend of white-mica grain size within the KNF is associated with a reduction of the closure temperature from the base (similar to 445 degrees C) to the top (<400 degrees C) and explains the counter-intuitive trend of downward-increasing age of cooling in the footwall. The new data show that rapid cooling within the KNF of the eastern Tauern Window started sometime before 21 Myr according to the Ar-40/Ar-39 white-mica cooling ages and between 25-21 Myr according to the new Rb/Sr white-mica ages, i.e., shortly after the attainment of the thermal peak in the Tauern Window at similar to 25 Myr ago. These new data, combined with literature data, support earlier cooling in the eastern part of then Tauem Window than in the western part by some 3-5 Myr. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}