Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/50085
Title: The Catanda extrusive carbonatites (Kwanza Sul, Angola): An example of explosive carbonatitic volcanism
Authors: Campeny, Marc
Mangas, José 
Melgarejo, Joan C.
Bambi, Aurora
Alfonso, Pura
Gernon, Thomas
Manuel, José
UNESCO Clasification: 250613 Petrología ígnea y metamórfica
Keywords: Extrusive carbonatite
Carbonatite lava
Carbonatitic lapilli tuff
Angola
Catanda, et al
Issue Date: 2014
Publisher: 0258-8900
Journal: Bulletin of Volcanology 
Abstract: Carbonatite lavas and pyroclastic rocks are exposed in the volcanic graben of Catanda and represent the only known example of extrusive carbonatites in Angola. A new detailed geological map of the area is presented in this study as well as six different stratigraphic sections. Pyroclastic rocks, apparently unwelded, are dominant in the area and represented in all the stratigraphic columns. They form shallowly to moderately inclined layers, mostly devoid of internal structures, that range in thickness from several centimetres to metres. They are dominantly lapilli tuffs and minor tuffs occasionally comprising pelletal lapilli. Based on their different features and field relationships, at least five different pyroclastic lithofacies have been distinguished in the area. Carbonatitic lavas outcrop in the external parts of the Catanda graben, forming coherent layers interbedded with pyroclastic rocks. Calcite is the most common mineral in the lavas, but other accessory minerals such as fluorapatite, titaniferous magnetite, phlogopite, pyrochlore, baddeleyite, monticellite, perovskite, cuspidine and periclase have also been identified. At least four different types of lavas have been distinguished based on their mineral associations and textural features. This study reveals an overall abundance of pyroclastic material in comparison to lava flows in the Catanda area, suggesting that eruptive processes were dominated by explosive activity similar to what has been described in other carbonatite and kimberlite localities. The Catanda carbonatitic volcanism was associated with monogenetic volcanic edifices with tuff ring or maar morphologies, and at least seven possible eruptive centres have been identified in the area.
URI: http://hdl.handle.net/10553/50085
ISSN: 0258-8900
DOI: 10.1007/s00445-014-0818-6
Source: Bulletin Of Volcanology [ISSN 0258-8900], v. 76 (4), (Abril 2014)
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