Structural Interpretation and Tectonostratigraphy of High-Pressure Low-Temperature Blueschist Facies Rocks near Orhaneli, Bursa Province, Western Türkiye

Yıl 2024, Cilt: 12 Sayı: 1, 541 - 563, 26.01.2024

Ümit Yıldız

Öz

The Izmir-Ankara suture, a Neo-Tethyan collision zone between the Sakarya microcontinent (hanging wall) to the north and the Anatolide-Tauride block (footwall) to the south, including blueschist facies rocks near Dağgüney village, Orhaneli in Bursa, Türkiye, formed during the mid-Cretaceous. There are three main tectonostratigraphic units including high-pressure/low-temperature (HP-LT) rocks, mélange, and subophiolitic peridotites. Extensive exposures of lawsonite blueschist, graphitic mica schist, white mica schist, and marble there indicate HP-LT conditions of formation. In addition, the Tavsanli Zone contains two other rock sequences of significance to subduction-related evolution. These are mélange, considered to have formed in an accretionary complex that includes metamorphosed radiolarian chert, greenstone, meta-volcanic-tuff, amphibolite, white-mica-schist, blueschist and serpentinite, peridotite which contains dunite, harzburgite, and gabbro, interpreted to have formed as the oceanic lithosphere. Metamorphic foliation, defined by compositional layering and schistosity, trends generally ENE and dips gently northerly. Metamorphic lineation, defined by elongate calcite and sodic amphibole grains, trends WSW and gently plunges. Mesoscopic isoclinal folds are common in the blueschist facies rocks. The majority of the folds trend NNE-SSW and plunge gently eastward in the HP-LT rocks. There are at least four major fault types based on age, cross-cutting relationships, and orientation. Blueschist facies mineral assemblages were preserved in the HP-LT rocks, thus a rapid exhumation mechanism of buoyancy-driven flow is interpreted to have taken place within the subduction channel. The presence of blueschist, amphibolite, and white mica schist within the mélange suggests that exhumation occurred during subduction.

Anahtar Kelimeler

Lawsonite blueschist, Structural Geology, Tavsanli Zone, Tectonostratigraphy

Kaynakça

• [1] A. I. Okay, and D. L. Whitney, “Blueschists, eclogites, ophiolites and suture zones in northwest Turkey: a review and a field excursion guide,” Ofioliti, vol.35.2, pp. 131-172, 2010.
• [2] A. I. Okay, “Jadeite-chloritoid-glaucophane-lawsonite schists from northwest Turkey: unusually high P/T ratios in continental crust,” Journal of Metamorphic Geology, vol. 20, pp. 757-768, 2002.
• [3] M. Cetinkaplan, O. Candan, R. Oberhansli, and R. Bousquet, “Pressure temperature evolution of lawsonite eclogite in Sivrihisar; Tavşanlı Zone-Turkey,” Lithos, vol. 104, pp. 12-32, 2008.
• [4] A. I. Okay, “Tavşanlı Zone: the northern subducted margin of the Anatolide-Tauride Block,” Mineral Research and Exploration Bulletin, vol. 142, pp. 191-221, 2011.
• [5] A. I. Okay, N. B. W. Harris, and S. P. Kelley, “Exhumation of blueschists along a Tethyan suture in northwest Turkey,” Tectonophysics, vol. 285, pp. 275-299, 1998.
• [6] S. Sherlock, S. P. Kelley, S. Inger, N. Harris, and A. I. Okay, “40Ar-39Ar and Rb-Sr geochronology of high-pressure metamorphism and exhumation history of the Tavsanlı Zone, NW Turkey,” Contributions to Mineralogy and Petrology, vol. 137, pp. 44-58, 1999.
• [7] N. C. A. Seaton, D. L. Whitney, C. Teyssier, E. Toraman, and M. T. Heizler, “Recrystallization of high-pressure marble (Sivrihisar, Turkey),” Tectonophysics, vol. 479, pp. 241-253, 2009.
• [8] N. B. W. Harris, S. P. Kelley, and A. I. Okay, “Post-collision magmatism and tectonics in northwest Turkey,” Contributions to Mineralogy and Petrology, vol. 117, pp. 241-252, 1994.
• [9] A. I. Okay, and O. Tüysüz, “Tethyan sutures of northern Turkey,” Geological Society, London, Special Publications, vol. 156, pp. 475-515, 1999.
• [10] A. I. Okay, S. Kelley, “Jadeite and chloritoid schists from northwest Turkey: tectonic setting, petrology and geochronology,” Journal of Metamorphic Geology, vol. 12, pp. 455-466, 1994.
• [11] P. B. Davis, and D. L. Whitney, “Petrogenesis and structural petrology of high-pressure metabasalt pods, Sivrihisar, Turkey,” Contributions to Mineralogy and Petrology, vol. 156, pp. 217-241, 2008.
• [12] G. R. Droop, M. C. Karakaya, Y. Eren, and N. Karakaya, “Metamorphic evolution of blueschists of the Altınekin Complex, Konya area, south-central Turkey,” Geological Journal, vol. 40, pp. 127-153, 2005.
• [13] S. J. Lippard, A. W. Shelton, and I. G. Gass, “The Ophiolites of Northern Oman,” The Geological Society of London, Memoir, vol. 11, p. 178, 1986.
• [14] A. E. D. El-Shazly, R. G. Coleman, and J. G. Liou, “Eclogites and blueschists from northeastern Oman: Petrology and P-T evolution,” Journal of Petrology, vol. 31, pp. 629-666, 1990.
• [15] C. J. Warren, R. A. Parrish, D. J. Waters, and M. P. Searle, “Dating the geologic history of Oman's Semail ophiolite: insights from U-Pb geochronology,” Contributions to Mineralogy and Petrology, vol. 150, pp. 403-422, 2005.
• [16] M. Okrusch, and M. Brocker, “Eclogites associated with high-grade blueschists in the Cyclades archipelago, Greece: A review,” European Journal of Mineralogy, vol. 2, pp. 451-478, 1990.
• [17] R. B. Forbes, B. W. Evans, and S. P. Thurston, “Regional progressive high-pressure metamorphism, Seward Peninsula, Alaska,” Journal of Metamorphic Geology, vol. 2, pp. 43-54, 1984.
• [18] A. M. C. Sengor, and Y. Yılmaz, “Tethyan evolution of Turkey: A plate tectonic approach,” Tectonophysics, vol. 75, pp. 181-241, 1981.
• [19] A. I. Okay, “Alpine-Himalayan blueschists,” Annual Reviews of the Earth and Planetary Sciences, vol. 17, pp. 55-87, 1989.
• [20] A. I. Okay, “Geology and blueschist metamorphism of ophiolites in northwest Anatolia (Tavşanlı-Kutahya),” Turkish Geological Society Bulletin, vol. 24, pp. 85-95, 1981.
• [21] G. Topuz, A. I. Okay, R. Altherr, H. P. Meyer, and L. Nasdala, “Partial high-pressure aragonitization of micritic limestones in an accretionary complex, Tavşanlı Zone, NW Turkey,” Journal of Metamorphic Geology, vol. 24, pp. 603-613, 2006.
• [22] ArcGIS Desktop 10.0. (2011). Environmental Systems Research Institute, Redlands, CA.
• [23] A. L. Lisenbee, “Structural setting of the Orhaneli ultramafic massif near Bursa, northwestern Turkey,” Ph.D. dissertation, Geology Department, Pennsylvania State University, State College, PA, USA, 1972.
• [24] A. I. Okay, “Tectonics and High Pressure Metamorphism in northwest Turkey,” presented at the 32nd APAT International Geological Congress, Florence, Italy, Aug. 20-28, 2004.
• [25] A. I. Okay, “Lawsonite zone blueschists and a sodic amphibole producing reaction in the Tavşanlı region, northwest Turkey,” Contributions to Mineralogy and Petrology, vol. 75, pp. 179-186, 1980.
• [26] A. P. Onen, “Neotethyan ophiolitic rocks of the Anatolides of NW Turkey and comparison with Tauride ophiolites,” Journal of the Geological Society of London, vol. 160, pp. 947-962, 2003.
• [27] O. Kaya, O. Özkoçak, and A. L. Lisenbee, “Stratigraphy of the Pre-Jurassic Blocky Sedimentary Rocks to the South of Bursa, NW Turkey,” Bulletin of the Mineral Research and Exploration, vol. 109, pp. 15-24, 1989.
• [28] E. Gokten, and M. A. Floyd, “Stratigraphy and geochemistry of pillow basalts within the ophiolitic mélange of the Izmir–Ankara–Erzincan suture zone: implications for the geotectonic character of the northern branch of Neotethys,” International Journal of Earth Sciences vol. 96, pp. 725–741, 2007.
• [29] A. I. Okay, "Incipient blueschist metamorphism and metasomatism in the Tavşanli region, Northwest Turkey," Contributions to Mineralogy and Petrology, vol. 79.4, pp. 361-367, 1982.
• [30] N. Y. Bragin, and U. K. Tekin, “Age of radiolarian-chert blocks from the Senonian ophiolitic mélange (Ankara, Turkey),” The Island Arc, vol. 5, pp. 114-122, 1996.
• [31] U. K. Tekin, M. C. Goncuoglu, and N. Turhan, “First evidence of Late Carnian radiolarians from the Izmir-Ankara suture complex, central Sakarya, Turkey: implications for the opening age of the Izmir-Ankara branch of Neo-Tethys,” Geobios, vol. 35, pp. 127-135, 2002.
• [32] M. C. Goncuoglu, M. K. Yaliniz, and U. K. Tekin, “Geochemistry, tectonomagmatic discrimination and radiolarian ages of basic extrusives within the Izmir-Ankara suture belt (NW Turkey): time constraints for the Neotethyan evolution,” Ofioliti, vol. 31, pp. 25-38, 2006.
• [33] T. Lovering, “The origin of jasperoid in limestone,” Economic Geology and the Bulletin of the Society of Economic Geologists, vol. 57, pp. 861-889, 1962.
• [34] A. I. Okay, M. Satir, and C. K. Shang, “Ordovician meta granitoid from the Anatolide-Tauride Block, northwest Turkey: geodynamic implications,” Terra Nova, vol. 20, pp. 280-288, 2008.
• [35] O. Monod, J. Andrieux, Y. Gautier, and J. R. Kienast, “Pontides Taurides relationships in the region of Eskisehir (NW Turkey),” Bulletin of the Technical University of Istanbul, vol. 44, pp. 257-277, 1991.
• [36] T. Masuda, S. Nakayama, N. Kimura, K. Onodera, and A. Okamoto, “Triaxial stress state deep in orogenic belts: an example from Turkey,” Journal of Structural Geology, vol. 26, pp. 2203-2209, 2004.
• [37] Y. Eren, “Tuzgölü havzası güneybatısındaki (Altınekin-Konya) temel kayaçlarının jeolojisi. Haymana-Tuzgolu-Ulukisla Basenleri Uygulamali Calisma,” Türkiye Petrol Jeologlari Dernegi Ozel Sayısı, vol. 5, pp. 113-126, 2000.