Petrological studies of Neoproterozoic serpentinized ultramafics of the Nubian Shield: spinel compositions as evidence of the tectonic evolution of Egyptian ophiolites

• Autorzy: Azer M. K.

Identyfikatory

DOI

10.2478/agp-2014-0006

• Języki publikacji: EN

Abstrakty

EN

The mafic-ultramafic rocks of the Gabal El-Degheimi area, Central Eastern Desert of Egypt, are parts of an ophiolitic section. The ophiolitic rocks are dismembered and tectonically enclosed within, or thrust over, island arc assemblages. Serpentinites, altered slices of the upper mantle, represent a distinctive lithology of the dismembered ophiolites. Some portions of the serpentinized rocks contain fresh relicts of primary minerals such as chromian spinel and olivine. The abundance of bastite and mesh textures suggests harzburgite and dunite protoliths, respectively, for these serpentinites. Some fresh cores of chromian spinel are rimmed by ferritchromite and Cr-magnetite. The development of alteration rims around chromian spinel cores indicates their formation during prograde alteration and under oxidizing conditions during lower amphibolite facies metamorphism. Fresh chromian spinels are characterized by high contents of Cr₂O₃ (48.92–56.74 wt. %), Al₂O₃ (10.29–20.08wt. %), FeO (16.24–28.46 wt. %) and MgO (4.89–14.02 wt. %), and very low TiO₂ contents (<0.16 wt. %). The analyzed fresh chromian spinels have high Cr# (0.62–0.79) characteristic of spinels in mantle peridotite that has undergone some degree of partial melting. The data presented here suggest that the mantle peridotites of the Gabal El-Degheimi area are similar to forearc peridotites of suprasubduction zone environments.

Słowa kluczowe

EN

Neoproterozoic; Serpentinite; Arabian-Nubian Shield; chromian spinel; fore-arc

PL

neoproterozoik; serpentynit; spinel

• Wydawca: Faculty of Geology of the University of Warsaw ; Komitet Nauk Geologicznych PAN
• Czasopismo: Acta Geologica Polonica
• Rocznik: 2014
• Tom: Vol. 64, no. 1
• Strony: 113--127
• Opis fizyczny: Bibliogr. 72 poz., il.

Twórcy

autor

Azer M. K.

• Geology Department, National Research Centre, 12622-Dokki, Cairo, Egypt

Bibliografia

• 1. Abd El-Rahman, Y., Polat, A., Dilek, Y., Fryer, B.J., El-Sharkawy, M. and Sakran, S. 2009. Geochemistry and tectonic evolution of the Neoproterozoic incipient arcfore-arc crust in the Fawakhir area, Central Eastern Desert of Egypt. Precambrian Research, 175, 116–134.
• 2. Abdel Aal, A.Y., Farahat, E.S., Hoinken G. and El-Mahalawi, M.M. 2003. Ophiolites from the Egyptian Shield: A case for a possible inter-arc origin. Mitt. Osterr. Ges., 148, 81–83.
• 3. Abdel-Karim, A.M., Azzaz, S.A., Moharem, A.F. and El-Alfy, H.M. 2008. Petrological and geochemical studies on the ophiolite and island arc association of Wadi Hammariya, central Eastern Desert, Egypt. The Arabian Journal for Science and Engineering, 33, 117–138.
• 4. Abdelsalam, M.G. and Stern, R.J. 1996. Sutures and Shear Zones in the Arabian–Nubian Shield. Journal of African Earth Science, 23, 289–310.
• 5. Ahmed, A.H., Helmy, H.M., Arai, S., Yoshikawa, M., 2008. Magmatic unmixing in spinel rim late Precambrian concentrically-zoned mafic–ultramafic intrusions, Eastern Desert, Egypt. Lithos, 104, 85–98.
• 6. Ahmed, A.H., Gharib, M.E. and Arai, S. 2012. Characterization of the thermally metamorphosed mantle-crust transition zone of the Neoproterozoic ophiolite at Gebel Mudarjaj, south Eastern Desert. Lithos, 142-143, 67–83.
• 7. Akaad, M.K. and Abu El Ela, A.M. 2002. Geology of the basement rocks in the eastern half of the belt between latitudes 25[0]30´ and 26[0]30´N Central Eastern Desert, Egypt. Geological Survey of Egypt, Paper, 78.
• 8. Akaad, M.K. and Noweir, A.M. 1980. Geology and Lithostratigraphy of the Arabian Desert orogenic belt of Egypt between Lat. 25[0]35´ and 26[0]30´N. Bull. Inst. Applied Geol., King Abdul Aziz Univ., Jeddah, 3, 127–135.
• 9. Ali, K.A., Azer, M.K., Gahlan, H.A., Wilde, S.A., Samuel, M.D. and Stern, R.J. 2010. Age of formation and emplacement of Neoproterozoic ophiolites and related rocks along the Allaqi Suture, south Eastern Desert, Egypt. Gondwana Research, 18, 583–595.
• 10. Anzil, P.A., Guereschi, A.B. and Martino, R.D. 2012. Mineral chemistry and geothermometry using relict primary minerals in the La Cocha ultramafic body: A slice of the upper mantle in the Sierra Chica of Córdoba, Sierras Pampeanas, Argentina. Journal of South American Earth Sciences, 40, 38–52.
• 11. Arai, S. 1992. Chemistry of chromian spinel in volcanic rocks as a potential guide to magma chemistry. Mineralogical Magazine, 56, 173–184.
• 12. Arif, M. and Jan, M.Q. 2006. Petrotectonic significance of the chemistry of chromite in the ultramafic-mafic complexes of Pakistan. Journal of Asian Earth Sciences, 27, 628–646.
• 13. Azer, M.K. 2013. Evolution and economic significance of listwaenites associated with Neoproterozoic ophiolites in south Eastern Desert, Egypt. Geologica Acta, 11, 113–128.
• 14. Azer, M.K., Abu El-Ela F.F. and Ren, M. 2012. The petrogenesis of late Neoproterozoic mafic dyke-like intrusion in south Sinai, Egypt. Journal of Asian Earth Sciences, 54-55, 91–109.
• 15. Azer, M.K. and El-Gharbawy, R.I. 2011. Contribution to the Neoproterozoic layered mafic-ultramafic intrusion of Gabal Imleih, south Sinai, Egypt: Implication of post-collisional magmatism in the north Arabian-Nubian Shield. Journal of African Earth Sciences, 60, 253–272.
• 16. Azer, M.K. and Khalil, A.E.S. 2005. Petrological and mineralogical studies of Pan-African serpentinites at Bir Al-Edeid area. Central Eastern Desert, Egypt. Journal of African Earth Sciences, 43, 525–536.
• 17. Azer, M.K., Samuel, M.D., Ali, K.A., Gahlan, H.A., Stern, R.J., Ren, M. and Moussa, H.E. 2013. Neoproterozoic ophiolitic peridotites along the Allaqi-Heiani Suture, South Eastern Desert, Egypt. Mineralogy and Petrology, 107, 829-848.
• 18. Azer, M.K. and Stern, R.J. 2007. Neoproterozoic (835-720 Ma) serpentinites in the Eastern Desert, Egypt: Fragments of fore-arc mantle. The Journal of Geology, 115, 457–472.
• 19. Barnes, S.J. 2000. Chromite in komatiites, 2. Modification during green-schist to mid-amphibolite facies metamorphism. Journal of Petrology, 41, 387–409.
• 20. Barnes, S.J. and Roeder, P.L. 2001. The Range of Spinel Compositions in Terrestrial Mafic and Ultramafic Rocks. Journal of Petrology, 42, 2279–2302.
• 21. Basta, F.F., Maurice, A.E., Bakhit, B.R., Ali, K.A. and Manton, W.I. 2011. Neoproterozoic contaminated MORB of Wadi Ghadir ophiolite, NE Africa: Geochemical and Nd and Sr isotopic constraints. Journal of African Earth Sciences, 59, 227–242.
• 22. Beccaluva, L., Coltori, M., Giunta, G. and Siena, F. 2004. Tethyan vs. Cordilleran ophiolites: a reappraisal of distinctive tectono-magmatic features of supra-subduction complexes in relation to subduction mode. Tectonophysics, 393, 163–174.
• 23. Bédard, J.H. 1999. Petrogensis of boninites from the Betts Cove ophiolite, Newfoundland, Canada: identification of subducted source components. Journal of Petrology, 40, 1853–1889.
• 24. Bloomer, S.H., Taylor, B., MacLeod, C.J., Stern, R.J., Fryer, P., Hawkins, J.W. and Johnson, L. 1995. Early arc volcanism and ophiolite problem: A perspective from drilling in the Western Pacific. In: Taylor, B., Natland, J. (Eds), Active Margins and Marginal Basins of the Western Pacific, Geophysical Monograph, Vol. 88. American Geophysical Union, Washington, DC, pp. 1–30.
• 25. Bonatti, E. and Michael, P.J. 1989. Mantle peridotites from continental rifts to oceanic basins to subduction zones. Earth and Planetary Science Letters, 91, 297–311.
• 26. Dick, H.B. and Bullen, T. 1984. Chromian spinel as a petrogenetic indicator in abyssal and Alpine-type peridotites and spatially associated lavas. Contribution to Mineralogy and Petrology, 86, 54–76.
• 27. El Sayed, M.M., Furnes, H. and Mohamed, F.H. 1999. Geochemical constraints on the tectonomagmatic evolution of the late Precambrian Fawakhir ophiolite, Central eastern Desert, Egypt. Journal of African Earth Sciences, 29, 515–533.
• 28. El Sharkawy, M.A. and El Bayoumi, R.M. 1979. The ophiolites of Wadi Ghadir area, Eastern Desert, Egypt. Annals of the Geological Survey of Egypt, 9, 125–135.
• 29. Evans, B.W. 2010. Lizardite versus antigorite serpentinite: magnetite, hydrogen, and life (?). Geology, 38, 879–882.
• 30. Farahat, E.S. 2008. Chrome-spinels in serpentinites and talc carbonates of the El Ideid-El-Sodmein District, central Eastern Desert, Egypt: their metamorphism and petrogenetic implications. Chemie der Erde, 68, 193–205.
• 31. Farahat, E.S., El Mahalawi, M.M. and Hoinkes, G. 2004. Continental back-arc basin origin of some ophiolites from the Eastern Desert of Egypt. Mineralogy and Petrology, 82, 81–104.
• 32. Farahat, E.S. and Helmy, H.M. 2006. Abu Hamamid Neoproterozoic Alaskan-type complex, south Eastern Desert, Egypt. Journal of African Earth Sciences, 45, 187–197.
• 33. Farahat, E.S., Hoinkes, G., Mogessie, A. 2011. Petrogenetic and geotectonic significance of Neoproterozoic suprasubduction mantle as revealed by the Wizer ophiolite complex, Central Eastern Desert, Egypt. International Journal of Earth Sciences, 100, 1433–1450.
• 34. Franz, L. and Wirth, R. 2000. Spinel inclusions in olivine of peridotite xenoliths from TUBAF seamount (Bismark Archipelago/Papua New Guinea): evidence for the thermal and tectonic evolution of the oceanic lithosphere. Contributions to Mineralogy and Petrology, 140, 283–295.
• 35. Gass, I.G. 1981. Pan-African (Upper Proterozoic) plate tectonics of the Arabian-Nubian Shield. In: Kröner, A. (Ed.), Precambrian plate tectonics, Elsevier, Amsterdam, 387–405.
• 36. González-Jiménez, J.M., Kerestedjian, T., Proenza, J.A. and Gervilla, F. 2009. Metamorphism on chromite ores from the Dobromirtsi ultramafic Massif, Rhodope Mountains (SE Bulgaria). Geologica Acta, 7, 413–429.
• 37. Hamdy, M.M., Harraz, H. Z. and Aly, G.A. 2013. Pan-African (intraplate and subduction-related?) metasomatism in the Fawakhir ophiolitic serpentinites, Central Eastern Desert of Egypt: mineralogical and geochemical evidences. Arabian Journal of Geosciences, 6, 13–33.
• 38. Helmy, H.M. and El Mahallawi, M.M. 2003. Gabbro Akarem mafic-ultramafic complex, Eastern Desert, Egypt: a Late Precambrian analogue of Alaskan-type complex. Mineralogy and Petrology, 77, 85–108.
• 39. Hirose, K. and Kawamoto, T. 1995. Hydrous partial melting of lherzolite at 1GPa: the effect of H2O on the genesis of basaltic magmas. Earth and Planetary Science Letters, 133, 463–473.
• 40. Jan, M.Q. and Windley, B.F. 1990. Chromian spinel-silicate chemistry in ultramafic rocks of the Jijal complex, Northwestern Pakistan. Journal of Petrology, 31, 667–715.
• 41. Johnson, L.E. and Fryer, P. 1990. The first evidence for MORBlike lavas from the outer Mariana fore-arc: geochemistry, petrography and tectonic implications. Earth and Planetary Science Letters, 100, 304–316.
• 42. Johnson, P.R., Kattan, F.H. and Al-Saleh, A.M. 2004. Neoproterozoic ophiolites in the Arabian Shield. In: Kusky, T.M. (Ed), Precambrian Ophiolites and Related Rocks. Developments in Precambrian Geology, 13, Elsevier, 129–162.
• 43. Kamenetsky, V.S., Crawford, A.J. and Meffre, S. 2001. Factors controlling chemistry of magmatic spinel: an empirical study of associated olivine, Cr-spinel and melt inclusions from primitive rocks. Journal of Petrology, 42, 655–671.
• 44. Khalil, A.E.S. and Azer, M.K. 2007. Supra-subduction affinity in the Neoproterozoic serpentinites in the Eastern Desert, Egypt: Evidence from mineral composition. Journal of African Earth Sciences, 49, 136–152.
• 45. Khedr, M.Z. and Arai, S. 2013. Origin of Neoproterozoic ophiolitic peridotites in south Eastern Desert, Egypt, constrained from primary mantle mineral chemistry. Mineralogy and Petrology, 107, 807-828.
• 46. Khudeir, A.A. 1995. Chromian spinel-silicate chemistry in peridotite and orthopyroxenite relicts from ophiolitic serpentinites, Eastern Desert, Egypt. Bulletin of Faculty of Science, Assiut University, 24, 221–261.
• 47. Khudeir, A.A., El Haddad, M.A. and Leake, B.E. 1992. Compositional variation in chromite from the Eastern Desert. Mineralogical Magazine, 56, 567–574.
• 48. Kröner, A. 1984. Late Precambrian plate tectonics and orogeny: a need to redefine the term Pan-African. In: Klerkx, J. and Michot, J. (Eds), African Geology, Teruren, 23–26.
• 49. Kröner, A., Stern, R.J., Linnabacker, P., Manton, W., Reischmann, T. and Hussein, I.M. 1991. Evolution of Pan-African island arc assemblages in the south Red Sea Hills, Sudan, and in SW Arabia as exemplified by geochemistry and geochronology. Precambrian Research, 53, 99–118.
• 50. Kröner, A., Todt, W., Hussein, I.M., Mansour, M. and Rashwan, A.A. 1992. Dating of late Proterozoic ophiolites in Egypt and Sudan using the single grain zircon evaporation technique. Precambrian Research, 59, 15–32.
• 51. Kusky, T.M., Abdelsalam, M., Tucker, R. and Stern, R. 2003. Evolution of the East African and Related Orogens, and the Assembly of Gondwana. Special Issue of Precambrian Research , 123, 81–344.
• 52. Loizenbauer, J., Wallbrecher, E., Fritz, H., Neumayr; P., Khudeir, A.A. and Kloetzli, U. 2001. Structural geology, simple zircon ages and fluid inclusion studies of the Meatiq metamorphic core complex: Implications for Neoproterozoic tectonics in the Eastern Desert of Egypt. Precambrian Research, 110, 357–383.
• 53. McElduff, B. and Stumpfl, E.F. 1991. The chromite deposits of the Troodos complex, cyprus: evidence for the role of a fluid phase accompanying chromite formation. Mineralium Deposita, 26, 307–318.
• 54. Mellini, M., Rumori, C. and Viti, C. 2005. Hydrothermally reset magmatic spinels in retrograde serpentinites: formation of ‘‘ferritchromit’’ rims and chlorite aureoles. Contributions to Mineralogy and Petrology, 149, 266–275.
• 55. Mondal, S.K., Baidya, T.K., Rao, K.N.G. and Glascock, M.D. 2001. PGE and Ag mineralization in a breccia zone of the Precambrian Nuasahi Ultramafic– mafic Complex, Orissa, India. Canada Mineralogy, 39, 979–996.
• 56. Murck, B.W. and Campbell, I.H. 1986. The effect of temperature, oxygen fugacity and melt composition on the behavior of chromium in basic and ultrabasic melts. Geochimica et Cosmochimica Acta, 50, 1871–1887.
• 57. Murton, B.J. 1989. Tectonic controls on boninite genesis. In: Saunders, A.D. and Norry, M.J. (Eds), Magmatism in the ocean basins. Geological Society of London, Special Publication, 42, 347–377.
• 58. Ohara, Y., Stern, R.J., Ishii, T., Yurimoto, H. and Yamazaki, T. 2002. Peridotites from the Mariana Trough: first look at the mantle beneath an active back-arc basin. Contribution to Mineralogy and Petrology, 143, 1–18.
• 59. Osman, A. 1995. The mode of occurrence of gold-bearing listvenite at El Barramiya gold mine, Eastern desert, Egypt. Middle East Research Centre, Ain Shams University, Earth Sciences Series, 9, 93–103.
• 60. Patchett, P.J. and Chase, C.G. 2002. Role of transform continental margins in major crustal growth episodes. Geology, 30, 39–42.
• 61. Reischmann, T. and Kröner, A. 1994. Late Proterozoic island arc volcanics from Gebeit, Red Sea Hills, north-east Sudan. Geologische Rundschau, 83, 547–563.
• 62. Roeder, P.L. 1994. Chromite: from the fiery rain of chondrules to the Kilauea Iki lava lake. Canada Mineralogy, 32, 729–746.
• 63. Saleh, G.M. 2006. The chromite deposits associated with ophiolite complexes, southeastern Desert, Egypt: Petrological and geochemical characteristics and mineralization. Chinese Journal of Geochemistry, 25, 307–317.
• 64. Shackleton, R.M. 1994. Review of late Proterozoic sutures, ophiolitic me´langes and tectonics of eastern Egypt and north Sudan. Geological Rundschau, 83, 537–546.
• 65. Sobolev, N.V. and Logvinova, A.M. 2005. Significance of accessory chrome spinels in identifying serpentinite paragenesis. International Geological Review, 47, 58–64.
• 66. Stern, R.J. and Hedge, C.E. 1985. Geochronologic and isotopic constraints on Late Precambrian crustal evolution in the Eastern Desert of Egypt. American Journal of Sciences, 285, 97–127.
• 67. Stern, R.J. 1994. Arc assembly and continental collision in the Neoproterozoic East African Orogen: implications for the consolidation of Gondwanaland. Annual Reviews of Earth and Planetary Science, 22, 319–351.
• 68. Stern, R.J., Johnson, P.R., Kröner, A. and Yibas, B., 2004. Neoproterozoic ophiolites of the Arabian-Nubian Shield. In: Kusky, T.M. (Ed.), Precambrian Ophiolites and Related Rocks. In: Developments in Precambrian Geology, 13, 95–128.
• 69. Suita, M. and Strieder, A. 1996. Cr-spinels from Brazilian mafic-ultramafic complexes: metamorphic modifications. International Geology Review, 38, 245–267.
• 70. Thalhammer, O.A.R., Prochaska, W. and Miihlhans, H.W. 1990. Solid inclusions in chrome-spinels and platinum group element concentrations from the Hochgrdssen and Kmubath Ultramafic Massifs (Austria). Contributions to Mineralogy and Petrology, 105, 66–80.
• 71. Zimmer, M., Krner, A., Jochum, K.P., Reischmann, T. and Todt, W. 1995. The Gabal Gerf complex: a Precambrian N-MORB ophiolite in the Nubian Shield, NE Africa. Chemical Geology, 123, 29–51.
• 72. Zoheir, B.A. and Lehmann, B. 2011. Listvenite-lode association at the Barramiya gold mine, Eastern Desert, Egypt. Ore Geology Reviews, 39, 101–115.