GEODYNAMIC PHASES OF THE ARAÇ MASSIF, WESTERN PONTIDS, KASTAMONU, TURKEY

Yıl 2000, Cilt: 122 Sayı: 122, 42 - 43, 01.03.2000

Doğan Aydal

Öz

This paper is concerned with the
geological, mineralogical and geochemical properties of Araç massif. The Araç
massif is mainly composed of ophiolites and metamorphic rocks. The age of the
metamorphic rocks, which are dominant rock group in the study area, are ranging
from Pre-Malm to Upper Cretaceous. K-Ar age determination were performed in
hornblendes derived from amphibolites, which are previously thought to be
Precambriam age in the study area. According to the KAr age results, which
gives 130-146 ma, suggests that the amphibolites were affected by retrograde
metamorphism, which took place in Berriasian (Lower Cretaceous). These ages are
believed to represent the metamorphism age, not the occurence age of the
formation. Because of this, the occurence of the Bekirçay formation should have
taken place before this retrograde metamorphism. Some very intensely altered
metaophiolitic bloks were found as xenolits in Bekirçay metamorphic units. Therefore
the age of the metaophiolites shoud have been older than the Bekirçay
formation. Mercimekdere metaophiolites were overlain, not only by Bekirçay
formation, but also by Kavacık formation, which is represented by
graphite-garnet micaschist in the study area. The Bekirçay formation and the
other above mentioned formation is overlayed discordantly by Palaeozoic
metasediments, namely the Dumantepe formation, which consists of various low
grade schists and phyllites. The Mesozoic is represented by Yongalıdağ formation,
Pelitveren ophiolitic melange and serpentinized, carbonatized and sillicified
rocks, so called listwaenites of the Gemiköy formation. Finally, this Mesozoic
formations were transgresively superseded by biosparite and biomicrite units of
the Araç formation. The area and surroundings were then affected by post Eocene
faulting. According to the geochemical investigations, it can easily be said
that ultramafic rocks occured as mantle fractionates and all mafic rocks were
originated from subalcaline tholeiitic magma. Amphibolites are found as
metaluminous, while garnet-micaschist are peraluminous and epidoteamphibolites
show both character in different places. Carbonaceous rocks in the study area
are found to be rich in calcite rather than dolomite and other minerals.

Anahtar Kelimeler

GEODYNAMIC, PHASES, ARAÇ MASSIF

Kaynakça

• Adamia, S.; Bergougnan, H.; Fourquin, C.; Haghipour, A.; Lordkipanidze, M.; Özgül, N.; Ricou, L.E. ve Zakariadze, G., 1980, The alpine-Midde-East between the Aegean and the Oman traverses. 26e Congr. Geol. Internat., Paris, Coll. C5 Geologie des chaines alpines issues de la Tethys. Mem. B.R.G.M. No., 115, 122-136.
• Aydal, D., 1989, Kastamonu ve Araç masifinde bulunan kromit cevherleri ile yan kayaçlarının mineralojik ve jeokimyasal incelemesi: Selçuk Üniversitesi Müh. Mim. Fak. Derg., V4, Say, 1, S18-19.
• 1990, Gold Bearing Listwaenites in the Araç mas- sif, Kastamonu- Turkey: Terra nova, V2, Number 1,43-52 pp.
• Aydın, M.; Şahintürk, ö., ve özçelik, Y., 1984, Araç- Daday-Karadere ve dolaylarının jeolojisi ve hidrokarbon olanakları: TPAŞ Arama Grubu Başkanlığı Rap., Arşiv No., 1948. 65 s.
• ; Serdar, H. S.; özçelik, Y; Akarsu, i.; Üngör A.; Çokuğraş, R. ve Kasar, S., 1986, Ballıdağ- Çangaldağı (Kastamonu) arasındaki bölgenin jeolojisi: Türkiye Jeol. Kur. Bült., 29,2, 1-16.
• Bergougnan, H. ve Forguin, C., 1982, Remnants of a pre- Late Jurassic ocean in northern Turkey: Fragments of Permian-Triassic Paleo-Tethys?: Discussion. Geol. Soc. Amer. Bull., 93, 929-932.
• Borchert, H., 1958, Türkiye'de iniyisal ofiyolitik magmatiz- maya ait Cr ve Cu cevheri yatakları, MTA yayl., No: 102, 161 s.
• Boztuğ, D., 1986, Daday-Devrekani masifi güneybatı kesi- minin jeolojisi hakkında ön rapor: MTA Arşiv No: 268, 11 s.
• 1988a, Daday-Devrekani masifi güneybatı kesimi mineralojik-petrografik ve jeokimyasal incelen- mesi. Doktora tezi, Hacettep Üniv., 232 s, (yayım- lanmamış), Ankara.
• 1992, Lithostratigraphic units and tectonics of the southwestern part of Daday-Devrekani massive, Western Pontides: Turkey. Bull. Of the Mineral Research and Exploration, 114,1-22, Ankara.
• ve Yılmaz, O., 1995, Daday-Devrekani masifi metamorfizması ve jeolojik evrimi, Kastamonu bölgesi, Batı Pontidler, Türkiye.
• Dercourt, J.; Zonenshain, L.F.; Ricou, L.E.; Kazmin, V.G.; Le pichon, X.; Knipper, A.L.; Grandjacquet, C. Shortshikov, l.M.; Geyssant, J.; Lepvrier, C. Pechersky, D.H.; Boulin, J.; Sibuet, J.C. Savostin, L.A.; Sorokhtin, O.; VVestphal, M.
• Bazhenov, M.L.; Lauer, J.P. ve Biju-Duval, B., 1986, Geological evolution of the Tethys belt from the Atlantic to the Pamirs since the Lias Tectonophysics, 123,241-315.
• Debon, F.; Le Fort, P, 1983, A chemical-mineralogical classification of common plutonic rocks and asso- ciations. Transactions of the Royal Society of Edinburgh: Earth Sciences, 73,135-149.
• Eren, R. H., 1979, Kastamonu Taşköprü bölgesi meta- mofritlerinin jeolojik, petrografik etüdü: İTÜ. Mim. Müh. Fak. Yayl., Doktora tezi, 143 s.
• Irvine, T.N. ve Baragar, W.R.A., 1971, A Guide to the Chemical classification of the common volkanic rocks. Can J. Earth Sci.,8,523-548.
• Jensen, L.S., 1976, A new cation plot for classifying sub- alkalic rocks, Ontario Div. Mines. Misc. pap.66.
• LeMaitre, R.W.; Bateman, P; Dudek, A.; Keller, J.; Lameyre J., Le Bas, M.J.; Sabine, P.A.; Schmith, R.; Sorenson, H.; Streckheisen, A.; Wooley A.R.; ve Zanettin, B., 1989, A classificationof igneous rocks and glossary of terms: Blackvvell Scentific Publication, 208p., Oxford.
• Maniar, D.P, ve Piccoli M. P, 1989, Tectonic discrimination of Granitoids, Geological Society of American Bulletin.v 101, p 635-643.
• Middlemost, E.A.K., 1985, Magmas and Magmatic rocks, Longman, London.
• Paccerillo, A.; Taylor, S.R., 1976, Geochemistry, of Eocene Calc-Alcaline Volcanic Rocks from the Kastamonu Area, Northern Turkey.
• Ricou, L.E.; Dercourt. J.; Geyssant, J.; Grandjacguet, C.; Lepvrier, C.; ve Biju-Duval, B., 1986, Geological constrains on the Alpine evolution of the Mediterranean Tethys: Tectonophysics, 123,83- 122.
• Robertson, A.H.F.; Dixon, J.E.; Aktaş, A.; Clift. P.D.; Degnan, P; Jones, G.; Morris, A.; Picckett, E.; Sharp, l. ve Ustaömer, T, 1991, Tectonic recon- structions of the Eastern Mediterranean region: Controversies, alternatives and possible solu- tions. Terra Abstracs, 3,322.
• Sawa, T, 1967, Araç bölgesindeki Cu, Fe ve Fe sülfit yatakları hakkında rapor: MTA Rap., No: 4048. (yayımlanmamış), Ankara.
• Şengör, A. M. C., 1979, The North Anatolian transform fault, its age, offset and tectonic Significance: Geol. Soc. of London Jour., 136, 269- 282.
• Yılmaz, Y. ve Ketin, l., 1980, Remnants of a Pre- Late Jurassic ocean in Northern Turkey: Fragments of Permian- Triassic Palaeo- Tethys; Geol. Soc. of Amer. Bull., l, 91, 599- 609.
• Şengör, A. M. C. ve Yılmaz, Y., 1981, Tethyan Evolution of Turkey, A Plate Tectonic Approch Tectonophysics: 75, 181-241.
• Şengün, M.; keskin, H.; Akçaören, F.; Altun, i.; Sevin, M.; Akat, U.; Armağan, F. ve Acar, Ş., 1990, Kastamonu yöresinin jeolojisi ve Paleotetisin evrimine ilişkin sınırlamalar: Türkiye Jeoloji Bült., 33, 1-16.
• Tüysüz, O., 1985, Kuzey Anadoluda iki farklı ofiyolit toplu- luğu: Eski ve yeni Tetis'in artıkları; Doğa, Müh. ve Çev., 10,2, 172-179.
• Ustaömer, T; Robertson, A.H.F. ve Yılmaz, Y., 1991, Paleotethyan tectonic evolution of the Central Pondites northern Turkey: Terra Abstracts, 3, 256.
• ve 1993, A late Paleozoic Early Mesozoic margin- al basin along the active Southern Continental margin of Eurasia: Evidance from the Central Pondites (Turkey) and adjacent regions. Geological Journal, 28, 219-238.
• Yılmaz, O., 1980, Daday- Devrekani masifi kuzeydoğu kesimi litostratigrafı birimleri ve tektoniği: HÛ. Yer bilimleri Derg., 5- 6, 101-135.
• 1981, Daday- Devrekani masifi Ebrek metamorfi- tinin petrografisi ve tüm kayaç kimyası: HÛ. Yer bilimleri Derg., 8, 71-82.
• 1983, Çangal metaofiyolitinin mineraolojik- petrog- rafik incelenmesi ve metamorfizma koşulları: HÛ. Yer bilimleri Derg., 10. 45- 48.
• ve Tüysüz, O., 1984, Kastamonu- Boyabat- Vezirköprü- Tosya arasında bölgenin jeolojisi (Ilgaz-Kargı masiflerinin etüdü): MTA jeoloji daire- si özel Rap., 275 s.
• ve Boztuğ, D., 1986, Kastamonu granitoid belt of Northern Turkey: First arc plutonism product related to the subduction product of the Palaeo- Tethys: Geology, 14, 179-183.
• ve Tüysüz, O., 1988, Kargı masifi ve dolaylarında Mesozoik tektonik birliklerinin düzenlemeleri sorununa bir yaklaşım: Tür. Pet. Jeol. Derg., C1, 1, 73-86.
• Wijkerslooth, P. De., 1941, Türkiye ve Balkanlardaki Cr cevheri zuhuratı ile bunların bu ülkelerin büyük tektoniğine olan maünasebetleri: MTA, Mem.Sayı1/26, 35-75.