DIAGENETIC HISTORY OF THE ROCK UNITS OF BOZKIR UNIT CONTROLLED BY THE TRIASSIC RIFTING, BOZKIR-KONYA

The Bozkır Unit representing the northern edge of the Taurus Belt comprises, from bottom to top, three distinct structural entities; the Upper Triassic pre-rift (Korualan Group), the Upper Triassic-Upper Cretaceous syn-rift (Huğlu Group) and the Jurassic-Cretaceous Boyalı Tepe Group as to their structural settings. The Korualan Group is represented by the alternations of carbonate (limestone, dolomitic limestone, dolomite) with radiolarite and chert intercalations and clastic rocks (sandstone, siltstone, mudstone, shale). The Huğlu Group is made up of volcanic (basalt, andesite) and pyroclastic (tuffaceous sandstone) rocks including radiolarite, limestone and clastic rock (sandstone, siltstone, shale) intercalations. The Boyalı Tepe Group is completely made of carbonate rocks. The carbonate-silisiclastic-volcanogenic rocks of the Bozkır Unit contain carbonate (calcite, dolomite), quartz, feldspar (plagioclase, anorthoclase), phyllosilicate (illite, chlorite, mixed-layered illite-chlorite / I-C, chlorite-vermiculite / C-V, chlorite-smectite / C-S, rare smectite), augite, hematite, analcime and heulandite in order of abundance. On the basis of illite Kübler Index data; Korualan and Huğlu Group reflect low grade diagenetic, high grade diagenetic and high grade diagenetic-anchizonal characteristics, respectively. The illite/micas of the pre-rift units and units related to the rifting have muscovitic, and phengitic and seladonitic compositions, respectively. The distributions of chondritenormalized trace and rare earth element (REE) contents in illites present similar trends for Korualan ve Huğlu groups, but the quantities of these elements slightly increase in the Huğlu Group. δ18O–δD isotopic compositions of water forming the illite minerals are different than that of sea water and are found to be between the Eastern Mediterranean Meteoric Water (EMMW) and magmatic water compositions. It also shows that temperature of the water forming illite minerals varies from low to high values. The findings from the rocks of Bozkır Unit suggest that pre- and syn-rift units have different mineralogical-petrographic and geochemical properties. The younger units within the rift due to extension and crustal thinning related to rifting must have been exposed in higher diagenetic conditions by more burial and heat with respect to older units on the edges.

___

  • Ahn, J., Peacor, D.R. 1985. Transmission electron microscopic study of diagenetic chlorite in Gulf Coast argillaceous sediments. Clays and Clay Minerals, 33, 228-236.
  • Alan, İ., Şahin, Ş., Keskin, H., Kop, A., Balcı, V., Böke, N., Bakırhan, B., Altun, İ., Esirtgen, T., Elibol, H., Arman, S., 2014. Orta Toroslar’da Hadim-Taşkent (Konya) yöresinde tektono-stratigrafik istiflerde yeni bulgular: Kartal Dağı istifi. 67. Türkiye Jeoloji Kurultayı, 14-18 April 2014, 60-61.
  • Andrew, T., Robertson, A.F., 2002. The Beyşehir–Hoyran– Hadim Nappes: genesis and emplacement of Mesozoic marginal and oceanic units of the northern Neotethys in southern Turkey. Journal of the Geological Society, London, 159, 529–543.
  • April, R.H. 1980. Regularly interstratified chlorite/vermiculite in contact metamorphosed red beds, Newark Group, Connecticut Valley. Clays and Clay Minerals, 28, 1-11.
  • Arkai, P. 1991. Chlorite crystallinity: an empirical approach and correlation with illite crystallinity, coal rank and mineral facies as examplified by Palaeozoic and Mesozoic rocks of northeast Hungary. Journal of Metamorphic Geology, 9, 723- 734.
  • Bailey, S.W. 1980. Structure of Layer Silicates. In: Crystal Structures of Clay Minerals and Their X-ray Identification, G.W. Brindley and G. Brown (Eds.), Mineralogical Society, London, 1-123.
  • Bailey, S.W. 1988. X-ray diffraction identification of the polytypes of mica, serpentine, and chlorite. Clays and Clay Minerals, 36, 193-213.