The Etendeka Igneous Province: Magma types and their stratigraphic distribution with implications for the evolution of the Paran -Etendeka flood basalt province

Marsh, J. S., Ewart, A., Milner, S. C., Duncan, A. R. and Miller, R. M. (2001) The Etendeka Igneous Province: Magma types and their stratigraphic distribution with implications for the evolution of the Paran -Etendeka flood basalt province. Bulletin of Volcanology, 62 6-7: 464-486. doi:10.1007/s004450000115

Author Marsh, J. S.
Ewart, A.
Milner, S. C.
Duncan, A. R.
Miller, R. M.
Title The Etendeka Igneous Province: Magma types and their stratigraphic distribution with implications for the evolution of the Paran -Etendeka flood basalt province
Journal name Bulletin of Volcanology   Check publisher's open access policy
ISSN 0258-8900
Publication date 2001-02
Year available 2000
Sub-type Article (original research)
DOI 10.1007/s004450000115
Volume 62
Issue 6-7
Start page 464
End page 486
Total pages 23
Editor T. H. Druitt
Place of publication Heidelberg, Germany
Publisher Springer
Collection year 2000
Language eng
Subject C1
260103 Vulcanology
780104 Earth sciences
Formatted abstract
Detailed geochemical and field data for the volcanic sequence and intrusions of the Etendeka Igneous Province are used to construct a stratigraphic framework for petrogenetic interpretation of the evolution of the Etendeka-Paraná continental flood volcanic event. Geochemical and petrographic characterization of over 1,000 analyzed samples allows 8 mafic and 17 silicic magma types to be recognized. Both silicic and mafic types can be grouped into high-Ti and low-Ti suites on the basis of elevated Ti relative to other elements. The mafic magmas are: Khumib (high-Ti), Tafelberg, Kuidas, Horingbaai, Huab, Tafelkop, Albin, and Esmeralda (all low-Ti). Amongst the silicic types, the Goboboseb, Springbok, Wereldsend, Grootberg, and Beacon low-Ti quartz latites, and the Nil Desperandum high-Ti latite have been described previously. In addition, the Hoas (low-Ti), Nadas, Sechomib, and Hoarusib, (all high-Ti) latites and the Fria (low-Ti), Sarusas, Ventura, Khoraseb, Naudé, and Elliott (all high-Ti) quartz latites are described for the first time here. There is a marked provinciality in the distribution of the high- and low-Ti suites, with the former concentrated in the Northern Etendeka region and the latter dominant in the Southern Etendeka. Stratigraphic distribution of magma types allows two new formations to be defined in the Northern Etendeka - the Khumib Formation of basaltic flows and the Skeleton Coast Formation dominated by silicic sheets. The geochemical provinciality hampers precise correlations between Northern and Southern Etendeka. Available evidence suggests that the lower part of the Awahab Formation in the Southern Etendeka is coeval with the lower part of the Khumib Formation and that the silicic units in the upper part of the Tafelberg Formation probably correlate with the Skeleton Coast Formation. The paucity of Khumib dykes in relation to Tafelberg dykes and their field relationships with regard to the volcanic sequence in the Northern Etendeka suggests that the main Khumib eruptive centers lay further north, consistent with southward thinning of the Khumib basalts. In the Southern Etendeka, the Doros complex is the eruptive center of the plume-derived Tafelkop basalts, which probably built a shield volcano within the regional flood lava field. This work indicates that the Etendeka has a greater variety of both silicic and low-Ti mafic magma types than are known from the SE Paraná. Detailed comparisons reveal that all the important silicic types in the Paraná have geochemical equivalents in the Etendeka. New correlations are Santa Maria=Fria, Ourinhos=Khoraseb, Guarapuava=Sarusas, thus extending the previously recognized correlations between Southern Etendeka quartz latites and the Caixas do Sul and Anita Garibaldi "rhyolites." These correlations emphasize that very large volume silicic systems develop with pronounced lithospheric rifting in continental flood basalt provinces.
Keyword Etendeka-ParanĂ¡ province
Magma types
Volcanic stratigraphy
Flood basalt
Silicic volcanics
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Earth Systems Science Computational Centre Publications
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Created: Tue, 10 Jun 2008, 12:49:33 EST