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Silicified serpentinite – a residuum of a Tertiary palaeo-weathering surface in the United Arab Emirates



Mineralogical studies of a silicified serpentinite from the United Arab Emirates throw light on the formative processes. The silicified serpentinite is a residuum of a palaeo-weathering surface that probably developed in a temperate climate with alternating wet and dry periods during middle Eocene to late Miocene times. The rock textures indicate that silicification occurred in a fluid-saturated zone. Silica precipitation is favoured at near-neutral pH. In this study we infer that these pH conditions of the mineralizing fluids could arise in a near-surface mixing zone where acidic meteoric and hyperalkaline groundwater fluids are mingled. This mingling is believed to have resulted from alternating processes of evaporation and precipitation that prevailed during dry and wet seasons, respectively. The silicified serpentinite is composed of > 95% quartz and exhibits a ghost texture of the protolith serpentinite. Preservation of the textures indicates an iso-volumetric grain-by-grain replacement by dissolution of Mg-silicate and simultaneous precipitation of either opal or microquartz as siliceous seeds. These were subsequently overgrown by silica that was probably remobilized from deeply weathered regolith elsewhere.


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Alsharhan, A. S. & Nairn, A. E. M. 1990. A review of the Cretaceous formations in the Arabian Peninsula and Gulf: Part III. Upper Cretaceous (Aruma Group) stratigraphy and paleogeography. Journal of Petroleum Geology 13, 247–66.
Barnes, I. & O'Neil, J. R. 1978. Present day serpentinisation in New Caledonia, Oman and Yugoslavia. Geochimica et Cosmochimica Acta 42, 144–5.
Barnes, I., O'Neil, J. R., Rapp, J. B. & White, D. E. 1973. Silica-carbonate alteration of serpentinite: wall rock alteration in mercury deposits of the California Coast Ranges. Economic Geology 68, 388–98.
Barros De Oliveira, S. M., Trescases, J. J. & Melfi, A. J. 1992. Lateritic deposits of Brazil. Mineralium Deposita 27, 137–46.
Bassett, H. 1954. Silicification of rocks by surface waters. American Journal of Science 252, 733–5.
Folk, R. L. & McBride, E. F. 1978. Radiolarites and their relation to subjacent “oceanic crust” in Liguria, Italy. Journal of Sedimentary Petrology 48, 1069–102.
Flörke, O. W., Graetsch, H., Martin, B., Röller, K. & Wirth, R. 1991. Nomenclature of micro- and non-crystalline silica minerals, based on structure and microstructure. Neues Jahrbuch Mineralogische Abhandlung 163, 1942.
Glennie, K. W., Boeuf, M. G. A., Hughes Clarke, M. W., Moody-Stuart, M., Pilaar, W. F. H. & Reinhardt, B. M. 1974. Geology of the Oman Mountains. The Royal Dutch Geological and Mining Society.
Iler, R. K. 1979. The Chemistry of Silica. New York: Wiley, 896 pp.
Leblanc, M. & Billaud, P. 1982. Cobalt arsenide ore bodies related to an upper Proterozoic ophiolite: Bou Azzer (Morocco). Economic Geology 77, 162–75.
Liu, Y., Olsen, A. A. & Rimstidt, J. D. 2006. Mechanism for the dissolution of olivine series minerals in acidic solutions. American Mineralogist 91, 455–8.
Luce, R. W., Bartlett, R. W. & Parks, G. A. 1972. Dissolution kinetics of magnesium silicates. Geochimica et Cosmochimica Acta 36, 3550.
Molly, E. W. 1959. Platinum deposits of Ethiopia. Economic Geology 54, 467–77.
Nasir, S., Al Sayigh, A. R., Al Harthy, A., Al-Khirbash, S., Al-Jaaidi, O., Musllam, A., Al-Mishwat, A. & Al-Bu'Saidi, S. 2007. Mineralogical and geochemical characterization of listwaenite from the Semail Ophiolite, Oman. Chemie der Erde 67, 213–28.
Nickel, E. H. & Thornber, M. R. 1977. Chemical constrains on the weathering of serpentinites containing nickel-iron sulphides. Journal of Geochemical Exploration 8, 235–45.
Nolan, S. C., Skelton, P. W., Clissold, B. P. & Smewing, J. D. 1990. Maastrichtian to early Tertiary stratigraphy and palaeogeography of the central and northern Oman Mountains. In The Geology and Tectonics of the Oman Region (eds Robertson, A. H. F., Searle, M. P. & Ries, A. C.), pp. 495519. Geological Society of London, Special Publication no. 49.
Ottemann, J. & Augustithis, S. S. 1967. Geochemistry and origin of “Platinum-Nuggets” in lateritic covers from ultrabasic rocks and birbirites of W. Ethiopia. Mineralium Deposita 1, 260–77.
Pokrovsky, O. S. & Schott, J. 2000. Forsterite surface composition in aqueous solutions: a combined potentiometric, electrokinetic, and spectroscopic approach. Geochimica et Cosmochimica Acta 64, 3299–312.
Pound, M. J., Haywood, A. M., Salzmann, U., Riding, J. B., Lunt, D. J. & Hunter, S. 2011. A Tortonian (Late Miocene, 11.61–7.25 Ma) global vegetation reconstruction. Palaeogeography, Palaeoclimatology, Palaeoecology 300, 2945.
Rice, S. J & Cleveland, G. B. 1955. Lateritic silification of serpentinite in the Sierra Nevada. Geological Society America Bulletin 66, 1660.
Rodgers, D. W. & Gunatilaka, A. 2003. Bajada formation by monsoonal erosion of a subaerial forebulge, Sultanate of Oman. Sedimentary Geology 154, 127–46.
Rosso, J. J. & Rimstidt, J. D. 2000. A high resolution study of forsterite dissolution rates. Geochimica et Cosmochimica Acta 64, 797811.
Siever, R. & Woodford, N. 1979. Dissolution kinetics and weathering of mafic minerals. Geochimica et Cosmochimica Acta 43, 717–24.
Shaetzl, R. J. & Anderson, S. 2005. Soils: Genesis and Geomorphology. Cambridge: Cambridge University Press.
Som, S. K. & Joshi, R. 2002. Chemical weathering of serpentinite and Ni enrichment in Fe oxide at Sukinda Area, Jajpur District, Orissa, India. Economic Geology 97, 165–72.
Snyder, R. L. & Bish, D. L. 1989. Quantitative analysis. In Modern Powder Diffraction (eds Bish, D. L. & Post, J. E.), pp. 101–44. Reviews in Mineralogy, vol. 20. Washington DC: Mineralogical Society of America.
Stein, C. L. & Kirkpatrick, R. J. 1976. Experimental porcelanite recrystalisation kinetics: a nucleation and growth model. Journal of Sedimentary Petrology 46, 430–5.
Stanger, G. 1985. Silicified serpentinite in the Semail nappe of Oman. Lithos 18, 1322.
Styles, M. T., Ellison, R. A., Arkley, S. L. B., Crowley, Q. G., Farrant, A., Goodenough, K. M., McKervey, J. A., Pharaoh, T. C., Phillips, E. R., Schofield, D. & Thomas, R. J. 2006. The Geology and Geophysics of the United Arab Emirates: Volume 2, Geology. Abu Dhabi, United Arab Emirates: UAE Ministry of Energy, 351 pp.
Thiry, M. & Millot, G. 1986. Mineralogical forms of silica and their sequence of formation in silcretes. Journal of Sedimentary Petrology 57, 343–52.
Thiry, M. & Simon-Coincon, S. 1996. Tertiary paleoweatherings and silcretes in the southern Paris Basin. Catena 26, 126.
Thiry, M. & Simon-Coincon, S. 1999. Diversity of continental silicification features: examples from the Cenozoic deposits in the Paris Basin and neighbouring basement. In Paleoweathering, Paleosurfaces and Related Continental Deposits, pp. 87–127. Special Publication of the International Association of Sedimentologists no. 27.
Trescases, J. J. 1973. Weathering and geochemical behaviour of the elements of ultramafic rocks in New Caledonia. Bureau of Mineral Resources, Geology and Geophysics, Canberra, Extract from Bulletin 141, pp. 149–161.
Venturelli, G., Contini, S. & Bonazzi, A. 1997. Weathering of ultramafic rocks and element mobility at Mt. Prinzera, Northern Apennines, Italy. Mineralogical Magazine 61, 765–78.
Williams, L. A., Parks, G. A. & Crerar, D. A. 1985. Silica diagenesis; I, Solubility controls. Journal of Sedimentary Petrology 55, 301–11.
Zachos, J., Dickens, G. M. & Zeebe, R. E. 2008. An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature 451, 279–83.


Silicified serpentinite – a residuum of a Tertiary palaeo-weathering surface in the United Arab Emirates



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