Abstract
In nature, zirconolite occurs as an accessory mineral in many different rock types, but the majority of reported occurrences are from carbonatites (magmatic carbonates) of geological age varying from a few million years to 2 billion years old. Within these 19 carbonatite occurrences, of which 15 have been studied in some detail, zirconolite displays varying degrees of alteration in six samples. This alteration ranges from incipient minor effects to major corrosion, recrystallization and complete replacement by secondary phases. The degree of alteration broadly correlates with either the age, or actinide content of the zirconolite (or both), and thus the extent and degree of metamictization. Changes in zirconolite composition with alteration include an increase in hydration (H2O), Si, Ba and Pb (possibly radiogenic in origin), and a decrease primarily in Ca and Fe. Th can be remobilized, and of the rare earth elements (REE), there is evidence that the heavy-REE are mobilized more readily than the light-REE. Using backscattered electron images and electron microprobe analyses, this study documents and illustrates the range of alteration features observed in zirconolite from several carbonatites, in terms of both compositional and textural changes, and provides some physico-chemical information on the fluids responsible for the alteration.
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References
K.L. Smith and G.R. Lumpkin, in Defects and Processes in the Solid State: Geoscience Applications. The McLaren Volume edited by J.N. Boland and J.D. Fitz Gerald (Elsevier, New York, 1993) pp. 401–422.
C.T. Williams and R. Gieré, Bull. Nat. Hist. Mus. Lond. (Geol.) 52, pp. 1–24 (1996).
R. Gieré, C.T. Williams and Schweiz. Mineral. Petrogr. Mitt., 78, pp. 433–459 (1998).
R. Gieré and C.T. Williams, Contrib. Mineral. Petrol. 112, 83–100 (1992).
R. Gieré, C.T. Williams, and G.R. Lumpkin, (1998). Mat. Res. Soc. Symp. Proc. 506, 1031–1032 (1998).
G.R. Lumpkin, R.A. Day, P.J. McGlinn, T.E. Payne, R. Gieré, and C.T. Williams, Mat. Res. Soc. Symp. Proc., 556, 793–800 (1999).
G.R. Lumpkin, K.L. Smith and R. Gieré, Micron 28, 57–68 (1997).
F. Bellatreccia, G. Della Ventura, E. Caprilli, C.T. Williams, and G.C. Parodi, Mineral. Mag., 63, 649–660 (1999).
S.G. Viladkar and W. Wimmenauer, Chem. Erde 52, 277–291 (1992)
A.G. Bulakh, A.R. Nesterov, C.T. Williams, and I.S. Anisimov, Mineral. Mag., 62, 837–846 (1998).
R. Gieré, M. Guggenheim, M. Düggelin, D. Mathys, C.T. Williams, G.R. Lumpkin, K.L. Smith, M.G. Blackford, and P. McGlinn, Electron Microscopy 94: Proc. 13th Int. Congr. on Electron Microscopy, Application in Material Sciences 2B, 1269–1270 (1994).
F. Wall and A.N. Mariano, in Rare Earth Minerals: Chemistry, Origin and Ore Deposits edited by A.P. Jones, F. Wall and C.T. Williams, (Chapman and Hall, London, 1996), pp. 193–226.
G.R. Lumpkin, K.L. Smith, M.G. Blackford, R. Gieré, and C.T. Williams, Mat. Res. Soc. Symp. Proc. 506, 215–222 (1998).
J. Malmstroem, J. Reusser, R. Gieré, G.R. Lumpkin, M. Dueggelin, D. Mathys, and R. Guggenheim. Mat. Res. Soc. Symp. Proc. 556, 165–172 (1999).
G.R. Lumpkin and R.C. Ewing, Amer. Mineral. 81, 1237–1248 (1996).
F. Wall, C.T. Williams, and A.R. Woolley, in Mineral Deposits: Processes to Processing, edited by C.J. Stanley et al., (Balkema Publishers, Rotterdam, 1999), pp. 687–690.
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Williams, C.T., Bulakh, A.G., Gieré, R. et al. Alteration Features in Natural Zirconolite from Carbonatites. MRS Online Proceedings Library 663, 945 (2000). https://doi.org/10.1557/PROC-663-945
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DOI: https://doi.org/10.1557/PROC-663-945