The geochemistry of late upper Proterozoic volcanic groups in the Red Sea Hills of NE Sudan; evolution of a late Proterozoic volcanic arc system

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doi: 10.1144/gsjgs.142.6.1221
Authors:Klemenic, P. M.; Poole, S.; Ali, S. E. M.
Author Affiliations:Primary:
Portsmouth Polytech., Dep. Geol., Portsmouth, United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.142 ( Part 6), p.1221-1233. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1985
Note:In English. 54 refs.; illus. incl. 3 tables, geol. sketch maps
Summary:The lavas of the Kadaweb and Homogar volcanic groups occur in the Sudanese part of the Nubian Shield and are late Proterozoic in age (723 and 671 m.y., respectively); they both display a calc- alkaline character and are similar in their lithology, phenocryst mineralogy and major-element composition, and geochemically they are similar to modern arc lavas associated with converging plate margins. A clear distinction between the two groups can be made, however, on the basis of the trace-element geochemistry of the basaltic components of the suites. The Homogar basalts are chemically more evolved and are enriched in the LIL elements and REE, having high La/Nb, Ce/YbN and 87Sr/86Sr ratios compared with those of the Kadaweb group. These chemical differences lead to the suggestions that the older lavas were erupted along an intra- oceanic island-arc system, while the younger Homogar lavas were extruded along a more evolved transitional arc, or possibly a continental margin. [R.A.H.]
Subjects:Alkaline earth metals; Basalts; Calc-alkalic composition; Cerium; Geochemistry; Igneous rocks; Isotopes; Lanthanum; Metals; Neoproterozoic; Niobium; Plate convergence; Plate tectonics; Precambrian; Proterozoic; Rare earths; Sr-87/Sr-86; Stable isotopes; Strontium; Trace elements; Upper Precambrian; Volcanic rocks; Ytterbium; Africa; East Africa; Nubian Shield; Red Sea Hills; Sudan; Homogar volcanic group; Kadaweb volcanic group; Northeastern Sudan
Coordinates:N180000 N203000 E0370000 E0360000
Abstract Numbers:86M/1990
Record ID:1986067000
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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