Prediction of weathering development in metarhyolites of the Ilgın (Konya) area, SW Turkey

Fresh to weathered metarhyolites crop out in the Ilgın (Konya) area of the Afyon-Bolkardağ Zone. Determination of the development of weathering was studied by physical (i.e. specific gravity, dry unit weight, saturated unit weight, porosity, void ratio, and degree of saturation by weight) and mechanical (i.e. point load) properties and the \"point rock change value\" (RCVp) and \"point rock change ratio\" (RCRp) values of the metarhyolite rock samples. The samples were classified in 3 groups (i.e. A, B, and C) representing degree of weathering from weathered to fresh rocks based on their RCVp and RCRp values. The K2O values are 7.09 wt.%, 8.62 wt.%, and 8.75 wt.% and the matrix ratios are 60%-70%, 50%-60%, and 20%-25% for groups A, B, and C, respectively. The RCVp and RCRp values of the studied samples range between 0.952 and 0.99 and 4.973% and 0.989%, respectively. Calculations show that metarhyolites will be completely changed by weathering at a 9.01% RCRp value according to metarhyolite alkali values varying in the 8.12%-9.40% range, with the average value being 8.89%. At the end of the rock change processes by weathering, the rocks remain chemically as metarhyolite, while their physico-mechanical properties and mineralogical compositions change to become soil. The average K-Ar ages vary between 60.4 ± 0.9 Ma and 64.1 ± 2.00 Ma. The whole-rock alteration can furthermore be predicted by the relationships between the RCRp and K-Ar ages of the 3 groups, which indicate that the rocks will be fully altered in the next 4.593 and 9.393 Ma. The whole-rock alteration will be completed for group A rocks in 4.6 Ma, for group B rocks in 7.2 Ma, and group C rocks in 9.4 Ma, provided that all the weathering agents take effect under the same conditions across the area.

Prediction of weathering development in metarhyolites of the Ilgın (Konya) area, SW Turkey

Fresh to weathered metarhyolites crop out in the Ilgın (Konya) area of the Afyon-Bolkardağ Zone. Determination of the development of weathering was studied by physical (i.e. specific gravity, dry unit weight, saturated unit weight, porosity, void ratio, and degree of saturation by weight) and mechanical (i.e. point load) properties and the \"point rock change value\" (RCVp) and \"point rock change ratio\" (RCRp) values of the metarhyolite rock samples. The samples were classified in 3 groups (i.e. A, B, and C) representing degree of weathering from weathered to fresh rocks based on their RCVp and RCRp values. The K2O values are 7.09 wt.%, 8.62 wt.%, and 8.75 wt.% and the matrix ratios are 60%-70%, 50%-60%, and 20%-25% for groups A, B, and C, respectively. The RCVp and RCRp values of the studied samples range between 0.952 and 0.99 and 4.973% and 0.989%, respectively. Calculations show that metarhyolites will be completely changed by weathering at a 9.01% RCRp value according to metarhyolite alkali values varying in the 8.12%-9.40% range, with the average value being 8.89%. At the end of the rock change processes by weathering, the rocks remain chemically as metarhyolite, while their physico-mechanical properties and mineralogical compositions change to become soil. The average K-Ar ages vary between 60.4 ± 0.9 Ma and 64.1 ± 2.00 Ma. The whole-rock alteration can furthermore be predicted by the relationships between the RCRp and K-Ar ages of the 3 groups, which indicate that the rocks will be fully altered in the next 4.593 and 9.393 Ma. The whole-rock alteration will be completed for group A rocks in 4.6 Ma, for group B rocks in 7.2 Ma, and group C rocks in 9.4 Ma, provided that all the weathering agents take effect under the same conditions across the area.

___

  • Bell, F.G. 1994. Engineering in Rock Masses. Butterworth-Heinemann Ltd., Oxford.
  • Bozkurtoğlu, E. 2003. Çanakkale-Tuzla Yöresi Volkanik Kayaçlarında Süreksizliklerin Ayrışma-Alterasyon Olaylarına Etkisinin Araştırılması. PhD Thesis, İstanbul Technical University Faculty of Mines, İstanbul, Turkey (in Turkish; unpublished).
  • Bozkurtoğlu, E., Vardar, M., Suner, F. & Zambak C. 2006. A new numerical approach to weathering and alteration in rock using a pilot area in the Tuzla geothermal area, Turkey. Engineering Geology 87, 33-47.
  • Browne, P.R.L. 1998. Hydrothermal Alteration. Geothermal Institute, University of Auckland, Auckland, New Zealand.
  • Carroll, D. 1970. Rock Weathering. Plenum Press, New York.
  • Franklin, J.A. & Broch, E. 1972. The point load strength test. International Journal of Rock Mechanics and Mining Science 9, 669-6
  • IAEG Commission of Engineering Geological Mapping. 1979. Classification of rocks and soils for engineering geological mapping. Part 1 – Rock and soil materials. Bulletin of the International Association of Engineering Geology 19, 71-364.
  • Irvine, T.N. & Baragar, W.R.A. 1971. A guide to chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences 8, 523-548.
  • ISRM. 1985. Suggested method for determining point load strength. International Journal of Rock Mechanics and Mining Science 22/2, 53-60.
  • Okay, A.I. & Tüysüz, O. 1999. Tethyan sutures of northern Turkey. In: Durand, B., Jolivet, L., Horvath, F. & Seranne, M. (eds), The Mediterranean Basins: Tertiary Extension within the Alpine Orogeny. Geological Society of London, Special Publication, 475-5
  • Özdamar, Ş. 2011. Geochemistry and K-Ar ages of metasedimentary and metasomatized high-K metavolcanic rocks in the AfyonBolkardağ Zone (Ilgin-Konya), SW Turkey. İTU Scientific Research Project 33366 (unpublished data).
  • Özdamar, Ş., Roden, M.F., Esenli, F., Uz, B. & Wampler, J.M. 2012. Geochemical features and K-Ar age data from metadetrital rocks and high-K metasomatized metarhyolites in the AfyonBolkardağ Zone (Ilgin-Konya), SW Turkey. Neues Jahrbuch für Mineralogie-Abhandlungen 189/2, 155-176.
  • Winchester, J.A. & Floyd, P.A. 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology 20, 325-343.
  • Turkish Standards Institution. 1982. TS-699: Tabii Yapı Taşları Muayene ve Deney Metodları. Türk Standartları Enstitüsü, Ankara (in Turkish).
Turkish Journal of Earth Sciences-Cover
  • ISSN: 1300-0985
  • Yayın Aralığı: Yılda 6 Sayı
  • Yayıncı: TÜBİTAK
Sayıdaki Diğer Makaleler

Prediction of weathering development in metarhyolites of the Ilgın (Konya) area, SW Turkey

Erkan BOZKURTOĞLU, Şenel ÖZDAMAR, Hatice Ünal ERCAN

Comment on "Al-in-Hornblende Thermobarometry and Sr-Nd-O-Pb Isotopic Compositions of the Early Miocene Alaçam Granite in NW Anatolia (Turkey)"

Ferdi TATAR ERKÜL, Fuat ERKÜL

The efficacy of travertine as a palaeoenvironmental indicator: palaeomagnetic study of neotectonic examples from Denizli, Turkey

Bekir Levent MESCİ, Orhan TATAR, John D. A. PIPER, Halil GÜRSOY, Erhan ALTUNEL, Stephen CROWLEY

Tectonosedimentary development and palaeoenvironmental changes in the Acıgöl shallow-perennial playa-lake basin, SW Anatolia, Turkey

Cahit HELVACI, M. Cihat ALÇİÇEK, İbrahim GÜNDOĞAN, Ünsal GEMİCİ

The effects of linear coarse-grained slope channel bodies on the orientations of fold developments: a case study from the Middle Eocene-Lower Oligocene Kırkgeçit Formation, Elazığ, eastern Turkey

Hasan ÇELİK

Revised Late Campanian-Danian age of the melange-related turbiditic sequence in the Mersin area (Central Taurides, S. Turkey)

Hayati KOÇ, Kemal TASLI, Erol ÖZER

Tragulidae (Artiodactyla, Ruminantia) from the Middle Miocene Chinji Formation of Pakistan

Muhammad Akbar KHAN, Muhammad AKHTAR

Oligocene vegetation and climate characteristics in north-west Turkey: data from the south-western part of the Thrace Basin

Funda AKGÜN, Mehmet Serkan AKKİRAZ, Sariye Duygu ÜÇBAŞ, Mustafa BOZCU

AFC-Modeler: a Microsoft® Excel© workbook program for modelling assimilation combined with fractional crystallization (AFC) process in magmatic systems by using equations of DePaolo (1981)

Mehmet KESKİN

Comment on "Al-in-Hornblende Thermobarometry and Sr-Nd-O-Pb Isotopic Compositions of the Early Miocene Alaçam Granite in NW Anatolia (Turkey)"

Ferdi TATAR ERKÜL, Fuat ERKÜL