Late Proterozoic island arc volcanics from Gebeit, Red Sea Hills, north-east Sudan

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Authors:Reischmann, T.; Kröner, A.
Author Affiliations:Primary:
Johannes Gutenberg-Universität, Institut für Geowissenschaften, Mainz, Federal Republic of Germany
Universität Mainz, Federal Republic of Germany
Volume Title:Geology of Northeast Africa
Volume Authors:Schandelmeier, H., editor; Stern, R. J.
Source:Geology of Northeast Africa, edited by H. Schandelmeier, R. J. Stern and A. Kröner. Geologische Rundschau, 83(3), p.547-563. Publisher: Springer International, Berlin, Federal Republic of Germany. ISSN: 0016-7835
Publication Date:1994
Note:In English. 42 refs.; illus., incl. 6 tables, geol. sketch map
Summary:Voluminous volcanic rocks in the area of Gebeit, N Red Sea Hills (Sudan), can be divided into four groups: 1) cpx-phyric basalts with clinopyroxene and plagioclase as the dominant phenocrysts; 2) hbl-phyric basalts with hornblende, clinopyroxene, plagioclase -- including one rare dacite; 3) pl-phyric andesites with plagioclase phenocrysts in a matrix rich in magnetite; and 4) aphyric basalts. For an explanation, more than one magma source reservoir is required. Mineral and whole-rock Sm/Nd data for the cpx- and hbl-phyric basalts yield an isochron age of 832 ± 26 m.y. (εNdt = 6.74 ± 0.19) interpreted as the age of eruption. The Nd and Sr isotopic data rule out any significant influence of older continental crust in Gebeit volcanics formation; the Gebeit terrain is a segment of juvenile crust originating in a subduction-related environment and supports the arc accretion model for the Arabian-Nubian Shield. [K.v.G.]
Subjects:Absolute age; Alkaline earth metals; Chemical composition; Crystal fractionation; Dates; Igneous rocks; Island arcs; Isotope ratios; Isotopes; Metals; Mineral composition; Nd-144/Nd-143; Neodymium; Neoproterozoic; Precambrian; Proterozoic; Rare earths; Sm/Nd; Sr-87/Sr-86; Stable isotopes; Strontium; Terranes; Trace elements; Upper Precambrian; Volcanic rocks; Zirconium; Africa; Arabian Peninsula; Arabian Shield; Asia; East Africa; Nubian Shield; Red Sea Hills; Sudan; Gebeit Mine; Gebeit Terrane; Initial neodymium
Abstract Numbers:95M/3475
Record ID:1995038454
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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