Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Geochronology and Pseudostratigraphy of Kahnuj Ophiolitic Complex

Document Type : Original Research Paper

Authors
1 Doctoral student of Geology, Faculty of Science, Tarbiat-e-Modarres University, Tehran, Iran
2 Department of Geology, Faculty of Science, University of Tehran, Tehran, Iran
3 Geological Survey of Iran, Tehran, Iran
4 IUEM, Universite de Bretagne Occidentale, 29285 Brest Cedex, France
Abstract
The Kahnuj Ophiolite Complex is mainly comprised of layered gabbros, isotropic gabbros, intermediate to acidic rocks such as diorite or plagiogranite, sheeted dyke, pillow lava, and pelagic limestone. Some fossils of Late Jurassic to Early Cretaceous age are observed in the limestone. The isotopic age determination for amphiboles, using K-Ar method, fairly correlates with that of paleontological studies. These studies reflect 136 to 165 my. (Dogger- Neocomian) for the amphiboles, whereas the ages for whole rocks and some of the plagioclases due to rejuvenation are usually younger than amphiboles. Some of the plagioclase crystals are doubtfully much older (Precambrian).
A younger potassic granite that is probably contemporaneous to the complex emplacement intrudes all the constituents of the complex.
Keywords

Subjects


Alavi, M., 1991- Sedimentary and Structural characteristics of the paleotethys remnants in northeastern Iran. Geol. Soc. Amer. Bull. 103, 983-992.
Alavi, M., 1994- Tectonics of the Zagros orogenic belt of Iran: New data and interpretations. Tectonophysics, 229, 211-238.
Alavi- Tehrani, N., 1977- Ophiolitic rocks of Sabzevar region. Proc. Second Geol. Sym. of Iran. N.O.I.C. Tehran, pp 42-62.
Alavi- Tehrani, N., 1980- The distribution of ophiolites in Iran and their significance. Ofioliti, 2, 315-334.
Arvin, M. and Robinson, P.T., 1994- The petrogenesis and tectonic setting of lavas from the Baft Ophiolitic Melange, Southwest of Kerman, Iran. Can. J. earth Sci. 31, 824-834.
Arvin, M. and Shokri, E., 1997- Genesis and eruptive environment of basalts from the Gogher ophiolitic melange, Southwest of Kerman, Iran. Can. J. Earth Sci. 31, 824-834.
Berberian, M., King G.C.P., 1981- Towards a paleogeography and tectonic evolution of Iran. Canadian journal of Science, 18, 210-265.
Davoudzadeh, M., 1972- Geology and petrography of the area north of Nain, Central Iran. Geol. Surv. Reprt. No 14.
Desmons, J., Beccaluva, L., 1982- Mid-Ocean ridge and island-arc affinities in ophiolites from Iran: Paleotectonic implication (abstract). Ofioliti, 7(213), 233.
Difenbach, W., Davoudzadeh, M., Alavi- Tehrani, N. and Lensch, G., 1986- Paleozoic ophiolites in Iran: Geology, Geochemistry and Geodynamic implication. Ofioliti, 11(3), 305-338.
Farhoudi, G., Karig, D.E., 1977- Makran of Iran as an active arc system. Geology, 5, 664-668.
Funkhouser, J.G., Fisher, D.E. and Bonatti, E., 1968- Excess argon in deep-sea rocks: Earth and Planetary Sci. Letters, 5, 95-100.
Gansser, A., 1974- The ophiolite mélanges, a world-wide problem on Tethyan examples. Eclogae. Geol. Helvetiae. 67, 479-507.
Ghazi A.M., Hassanipak A.A., 1995- Petrogenesis and tectonic setting of the Band Ziarat ophiolite, southern Iran. Geol. Soc. Amer., Abstracts with Programs, 27 4325.
Glennie K.W., Haghes Clarke, M.W., Boeuf, M.G.A., Pilaar, W.F.H., Reinhardt, B.M., 1990- Inter-relationship of Makran-Oman Mountains belts of convergence. in: Robertson, A.H.F., Searle M.P., Ries A.C. (Eds.), The Geology and Tectonics of the Oman region. Spec. Publ. Geol. Soc. 49, 773-786.
Hart, S.R., 1964- The petrology and isotopic-mineral age relations of a contact zone in the Front Range, Colorado. J. geol., 72, 493-525.
Hassanipak, A.A., Chazi, A.M., Wampler, J.M., 1996- Rare earth element characteristics and K-Ar ages of the Band Ziarat ophiolite complex, southeastern Iran. Can.J. Earth Sci. 33, 1534-1542.
Haynes, S.J., Reynolds, P.H., 1980- Early development of Tethys and Jurassic ophiolite displacement. Nature, 283, 561-563.
Juteau, T. and Maury, R., 1999- The Oceanic Crust, from Accretion to Mantle recyling. Springer, 390p.
Lanphere, M.A., Pamic, J., 1983- 40Ar/39 Ar ages and tectonic setting of ophiolite from the Neyriz area, southeast Zagros Range, Iran. Tectonophysics, 96, 245-256.
Lensch, G., Mihm, A., Alavi-Tehrani, N., 1977- Petrography and geology of the ophiolite belt north of Sabzevar/Khorasan (Iran). NJb. Miner. Abh. 133, 156-178.
Mahood, G.A., Drake, R.E., 1982- K-Ar dating young rhyolitic rocks: A case study of the Sierra La Primavera, Jalisco, Mexico. Geological Society of America bulletin, 93, 1232-1241.
Majidi, B., 1978- Etude petrostructural de la region de Mashad, N-E Iran. These, Univ. Grenoble, France. 277p.
McCall, G.J.H., 1985- Explanatory text of the Minab quadrangle map: 1:250000. No. J13, Geological Survey of Iran, Tehran.
Mc Call, G.J.H., Kidd, R.G.W., 1981- The Makran, southeastern Iran: the anatomy of a convergent plate margin active from Cretaceous to present. In: Legett J. (Eds.), Trench-Fore arc geology, Spec. Publ. Geol. Soc. London, 10, 387-397.
McCall, G.J.H., 1997- The geotectonic history of the Makran and adjacent areas of southern Iran. Journal of Asian Earth Sciences, 15, 517-531.
Noghreyan, M.K., 1982- Evolution geochimique, mineralogique et structurale d'un edifice ophiolitique singulier: Le massif de Sabzevar (partie centrale) NE de L'Iran. These, Uni. Nancy, France, 239p.
Ricou, L.E., 1994- Tethys reconstructed: plates, continental fragments and their boundaries since 260 Ma from Central America to South-eastern Asia. Geodinamica Acta, 169-218.
Ricou, L.E., 1971- Le croissant ophiolique peri-arabe. Une ceinture de naooes mises en place au creatace superieur. Rev. Geeogr. Phys. Geol. Dyn., 13, 327-350.
Sabzehei, M., 1974- Les melanges ophiolitiques de la region d' Esfandagheh (Iran meridional) Etude petrologique et structurale, Interpretation dans le cadre iranien. These, Uni. Grenoble, 205p.
Sabzehei, M., 1995- Layered ultramafic-mafic komatiitic lava flows and their bearing on the genesis of Iranian ophiolites. 30 th Inter. Geol. Vongr. Beijing China Abstract.
Sarkarinejad, K., 1985- The geology and tectonic setting of ophiolites and associated rocks in the Neyriz area, Southeast Iran. PhD thesis Univ. Wales.
Sarkarinejad, K., 1994- Petrology and tectonic setting of Neyriz Ophiolite, southeast Iran. In Circum- Pacific Ophiolites Proc. 29 th inter. Geol. Congr., 221-234.
Seidemann, D.E., 1977- Effects of submarine alteration on K- Ar dating of deep igneous rocks. Geological Society of America Bulletin, 88, 1660-1666.
Senghor, A.M.C., Altiner, D., Cin, A., Ustaosmer, T., Hsu, K., 1988- Origin and assembly of the Tethside orogenic collage at the expense of Gondwana Land. in: Audley-charles M.G., Hallam A. (Eds.), Gondwana and Tethys, Spec. Publ. Geol. Soc. London, 37, 119-181.
Steiger, R. H., Juger, E., 1977- Subcommission of geochronology: Convention on the use of decay constanis in geo- and cosmochronology. Earth and Planetary Science Letters, 38, 359-362.
Stocklin, J., 1968- Structural history and tectonics of Iran: a review. Amer. Assoc. Petroleum Geol. Bull. 52, 1229-1258.
Stocklin, J., 1974- Possible ancient continental margin in Iran. in: burk C.A., Grake C.L. (Eds.), geology of continental margins, Springer, New York, pp. 873-887.
Stocklin, J., Eftekhar Nezhad, J., Hushmandzadeh, A., 1972- Central Lut reconnaissance. Geol. Surv. Iran. Rept. 22, 62p.
Takin, M., 1972- Iranian geology and continental drift in the Middle East. Nature, 235, 147-150.
Wallace, K., Ghazi, A.M., Hassanipak, A.A., Mahoney, J.J., Duncan, R.A., Hogen, L.G., 1997- 40Ar/39 Ar ages, preliminary isotopic analyses and REE concentrations of the Band Ziarat Ophiolite Complex, southeastern Iran. EOS, Trans. Amer. Geophys. Union, 79, T21C-20, p.654.
Wampler, J.M., Mahoney, J., Ghazi, A.M. and Hassanipak, A.A., 1996- REE characteristics, K/Ar ages and preliminary isotopic analyses of the Band Ziarat ophiolite complex, southeastern Iran. EOS, Trans. Amer. Geophys. Union, 78V541B-4, p.836.
Volume 9, 33-34
Autumn & Winter 2000, vol. 9, No. 33-34
Autumn 2000
Pages 50-61