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Carbonatitic lavas in Catanda (Kwanza Sul, Angola): mineralogical and geochemical constraints on the parental melt
Citation
Campeny, M and Kamenetsky, VS and Melgarejo, JC and Mangas, J and Manuel, J and Alfonso, P and Kamenetsky, MB and Bambi, ACJM and Goncalves, AO, Carbonatitic lavas in Catanda (Kwanza Sul, Angola): mineralogical and geochemical constraints on the parental melt, Lithos, 232 pp. 1-11. ISSN 0024-4937 (2015) [Refereed Article]
Copyright Statement
© 2015 Elsevier B.V. All rights reserved.
DOI: doi:10.1016/j.lithos.2015.06.016
Abstract
A set of small volcanic edifices with tuff ring and maar morphologies occur in the Catanda area, which is the only locality with extrusive carbonatites reported in Angola. Four outcrops of carbonatite lavas have been identified in this region and considering the mineralogical, textural and compositional features, we classify them as: silicocarbonatites (1), calciocarbonatites (2) and secondary calciocarbonatites produced by the alteration of primary natrocarbonatites (3). Even with their differences, we interpret these lava types as having been a single carbonatite suite related to the same parental magma. We have also estimated the composition of the parental magma from a study of melt inclusions hosted in magnetite microphenocrysts from all of these lavas. Melt inclusions revealed the presence of 13 different alkali-rich phases (e.g., nyerereite, shortite, halite and sylvite) that argues for an alkaline composition of the Catanda parental melts. Mineralogical, textural, compositional and isotopic features of some Catanda lavas are also similar to those described in altered natrocarbonatite localities worldwide such as Tinderet or Kerimasi, leading to our conclusion that the formation of some Catanda calciocarbonatite lavas was related to the occurrence of natrocarbonatite volcanism in this area. On the other hand, silicocarbonatite lavas, which are enriched in periclase, present very different mineralogical, compositional and isotopic features in comparison to the rest of Catanda lavas. We conclude that its formation was probably related to the decarbonation of primary dolomite bearing carbonatites.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | carbonatitic lavas, natrocarbonatites, silicocarbonatites, angola, catanda |
| Research Division: | Earth Sciences |
| Research Group: | Geochemistry |
| Research Field: | Geochemistry not elsewhere classified |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the earth sciences |
| UTAS Author: | Kamenetsky, VS (Professor Vadim Kamenetsky) |
| UTAS Author: | Kamenetsky, MB (Dr Maya Kamenetsky) |
| ID Code: | 102094 |
| Year Published: | 2015 |
| Funding Support: | Australian Research Council (DP130100257) |
| Web of Science® Times Cited: | 18 |
| Deposited By: | Earth Sciences |
| Deposited On: | 2015-07-28 |
| Last Modified: | 2017-11-02 |
| Downloads: | 0 |
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