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Petrogenesis of the Eppawala carbonatites, Sri Lanka: A cathodoluminescence and electron microprobe study

Citation

Pitawala, A and Lottermoser, BG, Petrogenesis of the Eppawala carbonatites, Sri Lanka: A cathodoluminescence and electron microprobe study, Mineralogy and Petrology, 105, (1-2) pp. 57-70. ISSN 0930-0708 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 Springer-Verlag.

DOI: doi:10.1007/s00710-012-0193-y

Abstract

Field and petrographic investigations, cathodoluminescence (CL) studies as well as microprobe analyses of major rock-forming minerals were conducted to establish the crystallization processes in the Eppawala carbonatites, Sri Lanka. The well preserved magmatic textures and crystal morphologies combined with the chemistry of apatite, calcite and dolomite indicate two major stages of crystal growth, which were accompanied by dynamic crystallization conditions. Initially, nucleation of apatite, ilmenite and possibly olivine was associated with rapid crystal growth during slow cooling of the carbonatite melt at depth. The heat loss through the roof and crystallization processes induced the development of turbulent convective currents, which in turn prevented further nucleation and growth of crystals and led to the dispersion of these earlier formed crystals within the magma chamber. Then, rapid upward movement of magma along structural weaknesses led to (i) the transport of mineral clusters, (ii) deformation of ilmenite, (iii) fracturing of apatite and (iv) the emplacement of the carbonatite melt as dykes. Here, the conditions were favourable for the simultaneous crystallization of magnetite, calcite and dolomite in a non-turbulent environment. Subsequent subsolidus alteration caused the hydrothermal overprint of the documented mineral assemblages, particularly along grain boundaries. The study demonstrates that detailed textural examinations of carbonatites combined with mineral chemical analyses and CL investigations can reveal the crystallization processes within carbonatite melts. © 2012 Springer-Verlag.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Mineralogy and Crystallography
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Lottermoser, BG (Professor Bernd Lottermoser)
ID Code:81595
Year Published:2012
Web of Science® Times Cited:3
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2012-12-17
Last Modified:2017-10-30
Downloads:1 View Download Statistics

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