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Moving reactive interfaces and fractal carbonate replacement patterns in serpentinites: evidence from the southern Iberia Abyssal Plain

Published online by Cambridge University Press:  05 July 2018

L. J. Hopkinson ,
S. Dee  and
C. A. Boulter
L. J. Hopkinson
Affiliation:
School of Ocean and Earth Science, University of Southampton, Southampton Oceanography Centre, Empress Dock, European Way, Southampton, SO14 3ZH, UK
S. Dee
Affiliation:
Alastair Beach Associates Ltd, 11 Royal Exchange Square, Glasgow G1 3AJ, UK
C. A. Boulter*
Affiliation:
School of Ocean and Earth Science, University of Southampton, Southampton Oceanography Centre, Empress Dock, European Way, Southampton, SO14 3ZH, UK
*
*E-mail: [email protected]
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Abstract

Serpentinized ultramafic rocks recovered from beneath the southern Iberia Abyssal Plain (Ocean Drilling Programme Leg 173) provide the first record of fractal carbonate replacement patterns in a serpentinite. The patterns are expressed as microscopic branching aggregates (clusters) of aragonite disseminated throughout the serpentinites. Aragonite growth was the final mineralization event. The aragonite diminishes rapidly in quantity from an essential to a trace component of the serpentinite over a distance of ∼40 m from a normal fault. Decreasing abundance of aragonite away from the normal fault links the growth of the carbonate to the multistage hydrothermal mineralization associated with the fault.

Aragonite clusters are concentrated in picrolite, where they are interwoven with colloid-sized chrysotile, and show fractal growth habits. Areas adjacent to the clusters are sites of Mg enrichment of the serpentine medium relative to aragonite-free picrolite. It is interpreted that the aragonite clusters result from incursions of reactive seawater solutions through fine-scale pore structures in and around the fault in response to pressure gradients emanating from active tectonism. Cluster growth is interpreted to be a percolation phenomenon and provides a novel source of information on the nature of fine-scale reactive fluid flow, pore-space connectivity, and carbonate replacement processes in serpentinites.

Keywords

serpentinitefractal growth patternsviscous fingersaragonite
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 5 , October 2000 , pp. 791 - 800
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

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Footnotes

†

Current address: Department of Earth Sciences, College of Science, Sultan Qaboos University, PO Box 50, Al-Khod 123, Muscat, Sultanate of Oman

References

Aharony, A, Oxaal, U., Murat, M., Meir, Y., Boger, F., Feder, J. and Jøssang, T. (1989) Growth and viscous fingers on percolating porous media. Pp. 83–9 in: Random Fluctuations and Pattern Growth: Experiments and Models (Stanley, E.H. and Ostrowsky, N., editors). NATO Advanced Study Institute.Google Scholar
Bales, R.C. and Morgan, J.J. (1985) Dissolution kinetics of chrysotile at pH 7 to 10. Geochim. Cosmochim. Acta, 49, 2281–8.CrossRefGoogle Scholar
Baronnet, A. and Devouard, B. (1996) Topology and crystal growth of natural chrysotile and polygonal serpentine. J. Crystal Growth, 166, 952–60.CrossRefGoogle Scholar
Beard, J.S. and Hopkinson, L.J. (2000) A fossil serpentinization related hydrothermal event, ODP Leg 173, Site 1068 (Iberia Abyssal Plain): Some aspects of mineral and fluid chemistry. J. Geophys. Res., (in press).CrossRefGoogle Scholar
Bonatti, E., Emilian, C., Ferrara, G., Honnorez, J. and Rydell, H. (1974) Ultramafic-carbonate breccias from the equatorial Mid Atlantic Ridge. Marine Geol., 16, 83–102.CrossRefGoogle Scholar
Bonatti, E., Lawrence, J.R., Hamlyn, P.R. and Breger, D. (1980) Aragonite from deep sea ultramafic rocks. Geochim. Cosmochim. Acta, 44, 1207–14.CrossRefGoogle Scholar
Buka, A., Palffy-Muhoray, P. and Racz, Z. (1987) Viscous fingering in liquid crystals. Phys. Rev., A36, 3984–9.CrossRefGoogle ScholarPubMed
Cressey, B.A. (1979) Electron microscopy of serpentinite textures. Canad. Mineral., 17, 741–56.Google Scholar
Daccord, G. (1987) Chemical dissolution of a porous medium by a reactive fluid. Phys. Rev. Lett., 58, 479–82.CrossRefGoogle ScholarPubMed
Fowler, A.D., Stanley, H.E. and Daccord, G. (1989) Disequilibrium silicate melt textures: fractal and non-fractal features. Nature, 341, 134–8.CrossRefGoogle Scholar
Francis, T.J.D. (1981) Serpentinization faults and their role in the tectonics of slow spreading ridges. J. Geophys. Res., 86, 11616–22.CrossRefGoogle Scholar
Frost, R.B. (1985) On the stability of sulfides, oxides, and native metals in serpentinite. J. Petrol., 26, 31–63.CrossRefGoogle Scholar
Garcia Ruiz, J.M., Otalora, F., Sanchez-Navas, A. and Higes-Rolando, F.J. (1995) The formation of manganese dendrites as the mineral record of flow structures. Pp. 307–17 in: Fractals in Geoscience (Kruhl, J.H., editor). Springer Verlag, Berlin.Google Scholar
German, C.R. and Parson, L.M. (1998) Distributions of hydrothermal activity along the Mid-Atlantic Ridge: interplay of magmatic and tectonic controls. Earth. Planet. Sci. Lett., 160, 327–41.CrossRefGoogle Scholar
Gibson, I.L., Beslier, M.-O., Cornen, G., Milliken, K.L. and Seifert, K. E. (1996) Major and trace element seawater alteration profiles in serpentinite formed during the development of the Iberia Margin, site 897. Pp. 519–28 in: Proc. ODP, Scientific Results, 149 (Whitmarsh, R.B., Sawyer, D.S., Klaus, A. and Masson, D.G., editors). Texas A&M.Google Scholar
Hopkinson, L.J. Roberts, S., Herrington, R.J. and Wilkinson, J.J. (1998) Geochemical self organisation of hydrothermal siliceous deposits, evidence from the TAG hydrothermal mound, 26°N Mid Atlantic Ridge. Geology, 26, 347–50.2.3.CO;2>CrossRefGoogle Scholar
Horváth, V., Vicsek, T. and Kertész, J. (1987) Viscous fingering with imposed uniaxial anisotropy. Phys. Rev, A35, 2353–6.CrossRefGoogle ScholarPubMed
Krawczyk, C.M., Reston, T.J., Beslier, M.-O. and Boillot, G. (1996) Evidence for detachment tectonics on the Iberia Abyssal Plain rifted margin. Pp. 603–15 in: Proc. ODP, Scientific Results, 149 (Whitmarsh, R.B., Sawyer, D.S., Klaus, A. and Masson, D.G., editors). Texas A&M.Google Scholar
Lenormand, R. (1986) Pattern growth and fluid displacements through porous media. Physica A, 140, 114–23.CrossRefGoogle Scholar
Lenormand, R. and Daccord, G. (1989) Flow patterns in porous media. Pp. 69–74 in: Random Fluctuations and Pattern Growth: Experiments and Models (Stanley, E.H. and Ostrowsky, N., editors). NATO Advanced Study Institute.Google Scholar
Luce, R.W., Bartlett, R.W. and Parks, G.A. (1972) Dissolution kinetics of magnesium silicates. Geochim. Cosmochim. Acta, 36, 35–50.CrossRefGoogle Scholar
MacDonald, A.H. and Fyfe, W.S. (1985) Rate of serpentinization in seafloor environments. Tectonophysics, 116, 123–35.CrossRefGoogle Scholar
Milliken, K.L., Lynch, F.L. and Seifert, K.E. (1996) Marine weathering of serpentinites and serpentinite breccias, sites 897 and 899. Pp. 529–40 in: Proc. ODP, Scientific Results, 149 (Whitmarsh, R.B., Sawyer, D.S., Klaus, A. and Masson, D.G., editors). Texas A&M.Google Scholar
Murat, M. and Aharony, A. (1986) Viscous fingering and diffusion limited aggregates near percolation. Phys. Rev. Lett, 57, 1875–8.CrossRefGoogle Scholar
Naumann, A.W. and Dreshner, W.H. (1968) Colloidal suspensions of chrysotile asbestos: surface charge enhancement. J. Coll. Interf. Sci, 27, 133–9.CrossRefGoogle Scholar
Nittmann, J., Daccord, G. and Stanley, H.E. (1985) Fractal growth of viscous fingers: quantitative characterization of a fluid instability phenomenon. Nature, 314, 141–4.CrossRefGoogle Scholar
O’Hanley, D.S. (1991) Fault-related phenomena associated with hydration and serpentine recrystallization. Canad. Mineral, 29, 21–35.Google Scholar
O’Hanley, D.S. (1992) Solution to the volume problem in serpentinization. Geology, 20, 705–8.2.3.CO;2>CrossRefGoogle Scholar
O’Hanley, D.S. (1996) Serpentinites: Records of Tectonic and Petrological History. Oxford Monographs on Geology and Geophysics No. 34, Oxford University Press.Google Scholar
O’Hanley, D.S. and Offler, R. (1992) Characterisation of multiple serpentinization, Woodsreef, New South Wales. Canad. Mineral., 30, 1113–26.Google Scholar
Ortoleva, P. (1996) Geochemical Self-organization. Oxford Monographs on geology and geophysics, No. 23, Oxford University Press.Google Scholar
Oxaal, U., Murat, M., Boger, F., Aharony, A., Feder, J. and Jøssang, T. (1987) Viscous fingering on percolation clusters. Nature, 329, 32–7.CrossRefGoogle Scholar
Pacco, F., Van Gangh, L. and Fripiat, J.J. (1976) Étude par spectroscopie infrarouge et résonance magnétique nucléaire de la distribution homogéne des groupes silanols d’un gel de silice fibreux. Bull. Soc. Chim. fr. 7–8, 1022–6.Google Scholar
Pickup, S.L.B., Whitmarsh, R.B., Fowler, C.M.R. and Reston, T.J. (1996) Insight into the nature of the ocean continent transition off West Iberia from a deep multichannel seismic reflection profile. Geology, 24, 1079–82.2.3.CO;2>CrossRefGoogle Scholar
Schandl, E.S. and Naldrett, A.J. (1992) CO2 metasomatism of serpentinites, South of Timmins, Ontario. Canad. Mineral., 30, 93–108.Google Scholar
Stauffer, D. (1985) Introduction to Percolation Theory. Taylor & Francis, London.CrossRefGoogle Scholar
Viscek, T. (1989) Fractal Growth Phenomena. World Scientific, Singapore.Google Scholar
Whitmarsh, R.B., Beslier, M.-O. Wallace, P.J., Abe, N., Basile, C., Beard, J.S., Froitzheim, N., Gardien, V., Hebert, R, Hopkinson, L.J., Kudless, K., Louvel, V., Manatschal, G., Newton, A.C., Rubenach, M. J., Skelton, A.D.L., Smith, S.E., Takayama, H., Tompkins, M.J., Turrin, B.D., Urquhart, E., Wallrabe-Adams, H.J., Wilkens, R.H., Wilson, R.C.L., Wise, S.W. and Zhao, X. (1998) Proc. ODP Init. Reports, Vol. 173. Texas A&M.Google Scholar
Witten, T.A. and Sander, L.M. (1983) Diffusion limited aggregation. Phys. Rev., B27, 5686–97.CrossRefGoogle Scholar