Contributions to Mineralogy and Petrology

, Volume 162, Issue 6, pp 1215–1231

Acigöl rhyolite field, Central Anatolia (part 1): high-resolution dating of eruption episodes and zircon growth rates

  • Axel K. Schmitt
  • Martin Danišík
  • Noreen J. Evans
  • Wolfgang Siebel
  • Elena Kiemele
  • Faruk Aydin
  • Janet C. Harvey
Original Paper

DOI: 10.1007/s00410-011-0648-x

Cite this article as:
Schmitt, A.K., Danišík, M., Evans, N.J. et al. Contrib Mineral Petrol (2011) 162: 1215. doi:10.1007/s00410-011-0648-x

Abstract

Protracted pre-eruptive zircon residence is frequently detected in continental rhyolites and can conflict with thermal models, indicating briefer magma cooling durations if scaled to erupted volumes. Here, we present combined U-Th and (U-Th)/He zircon ages from the Acigöl rhyolite field (Central Anatolia, Turkey), which is part of a Quaternary bimodal volcanic complex. Unlike other geochronometers, this approach dates crystallization and eruption on the same crystals, allowing for internal consistency testing. Despite the overall longevity of Acigöl rhyolite volcanism and systematic trends of progressive depletion in compatible trace elements and decreasing zircon saturation temperatures, we find that zircon crystallized in two brief pulses corresponding to eruptions in the eastern and western part of the field during Middle and Late Pleistocene times, respectively. For Late Pleistocene zircon, resolvable differences exist between interior (average: 30.7 ± 0.9 ka; 1σ error) and rim (21.9 ± 1.3 ka) crystallization ages. These translate into radial crystal growth rates of ~10−13 to 10−14 cm/s, broadly consistent with those constrained by diffusion experiments. Rim crystallization and (U-Th)/He eruption ages (24.2 ± 0.4 ka) overlap within uncertainty. Evidence for brief zircon residence at Acigöl contrasts with many other rhyolite fields, suggesting that protracted zircon crystallization in, or recycling from, long-lived crystal mushes is not ubiquitous in continental silicic magma systems. Instead, the span of pre-eruptive zircon ages is consistent with autochthonous crystallization in individual small-volume magma batches that originated from basaltic precursors.

Keywords

Zircon (U-Th)/He Uranium series Calderas Rhyolite domes 

Supplementary material

410_2011_648_MOESM1_ESM.pdf (2.4 mb)
Online Resource 1: Field photographs from rocks of the Acigöl volcanic complex. (A) View of the N-S trending scarp cutting eastern group lavas (Boğazköy) overlain by pyroclastic fallout deposits (view facing N). (B) Close-up of the contact between Boğazköy lavas and Upper Acigöl Tuff (UAT). Contact is depositional with ash deposits subhorizontally overlying fragmented perlitic lava (contact location: N 38º31’37.3”, E 34º38’51.0”, elevation 1468 m). (C) Basaltic lava flow in Alacaşar village overlying pyroclastic fallout deposit (UAT sampling location ALA4 ~4 m below projected contact). (D) N facing view of western group domes. Picture is taken from Korudağ dome with Güneydağ dome in the foreground and Kaleci dome in the background. Karapinar village is located between Korudağ and Güneydağ, and Acigöl village to the W of Kaleci in the background. (PDF 2419 kb)
410_2011_648_MOESM2_ESM.pdf (73 kb)
Online Resource 2: U-Th zircon data analyzed by SIMS. (PDF 72 kb)
410_2011_648_MOESM3_ESM.pdf (44 kb)
Online Resource 3: U-Pb zircon data analyzed by SIMS. (PDF 44 kb)
410_2011_648_MOESM4_ESM.pdf (71 kb)
Online Resource 4: Results of combined U-Th and (U-Th)/He zircon dating. (PDF 71 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Axel K. Schmitt
    • 1
  • Martin Danišík
    • 2
    • 3
  • Noreen J. Evans
    • 2
    • 4
  • Wolfgang Siebel
    • 5
  • Elena Kiemele
    • 5
  • Faruk Aydin
    • 6
  • Janet C. Harvey
    • 7
  1. 1.Department of Earth and Space SciencesUniversity of California, Los AngelesLos AngelesUSA
  2. 2.John de Laeter Centre for Isotope Research, Applied GeologyCurtin UniversityPerthAustralia
  3. 3.Department of Earth and Ocean Sciences, Faculty of Science & EngineeringThe University of WaikatoHamiltonNew Zealand
  4. 4.CSIRO Earth Science and Resource EngineeringBentleyAustralia
  5. 5.Institute of GeosciencesUniversität TübingenTübingenGermany
  6. 6.Department of Geological EngineeringKaradeniz Technical UniversityCampus TrabzonTurkey
  7. 7.Geological and Planetary SciencesCalifornia Institute of TechnologyPasadenaUSA

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