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Title: Late Precambrian ensimatic volcanism in the Central Eastern Desert of Egypt

Abstract

Early stages in the geologic evolution of the Central Eastern Desert of Egypt (CED) reflect ensimatic, ocean-floor and island-arc volcanic activity. This thesis studies the stratigraphy, distribution, geochronology, and petrology of these volcanic rocks, providing insights into Late Precambrian crustal evolution in NE Africa and Arabia. A three-fold stratigraphy is preserved in the basement of the CED. A section of oceanic crust is basal. These Older Metavolcanics (OMV) are conformably overlain by Immature Metasediments (IM). The IM are dominated by volcanogenic wackes and breccias, with subordinate hematitic Fe-formation and jasper, marls, and conglomerates derived from older sial. The IM are conformably succeeded by calc-alkaline Younger Metavolcanics (YMV). OMV, IM, and YMV are restricted to the Central Eastern Desert, but analogous terranes are found in N. Arabia. The YMV and associated plutons are dated by Rb/Sr techniques. The CED is the youngest crustal domain in the Egyptian basement, being flanked by older Proterozoic crust to the north and south and by the Archean Saharan Craton to the west. The data show that an intense episode of instability, convection, and widespread melting occurred in the mantle beneath Afro-Arabia at the end of the Precambrian. A model is presented whereby NE Gondwanaland wasmore » rifted, 650-620 mya, along a N-S trend to form a Late Proterozoic proto-Red Sea. This basin was closed by reconvergence of the Saharan and E. Arabian cratons at about 620-600 mya.« less

Authors:
Publication Date:
Research Org.:
California Univ., San Diego (USA)
OSTI Identifier:
5473392
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; EGYPTIAN ARAB REPUBLIC; DESERTS; VOLCANIC ROCKS; AGE ESTIMATION; ORIGIN; PETROLOGY; STRATIGRAPHY; AFRICA; EARTH MANTLE; OCEANIC CRUST; PRECAMBRIAN ERA; VOLCANISM; ARID LANDS; DEVELOPING COUNTRIES; EARTH CRUST; GEOLOGIC AGES; GEOLOGY; IGNEOUS ROCKS; ROCKS; 580100* - Geology & Hydrology- (-1989); 580202 - Geophysics- Volcanology- (1980-1989)

Citation Formats

Stern, R J. Late Precambrian ensimatic volcanism in the Central Eastern Desert of Egypt. United States: N. p., 1979. Web.
Stern, R J. Late Precambrian ensimatic volcanism in the Central Eastern Desert of Egypt. United States.
Stern, R J. 1979. "Late Precambrian ensimatic volcanism in the Central Eastern Desert of Egypt". United States.
@article{osti_5473392,
title = {Late Precambrian ensimatic volcanism in the Central Eastern Desert of Egypt},
author = {Stern, R J},
abstractNote = {Early stages in the geologic evolution of the Central Eastern Desert of Egypt (CED) reflect ensimatic, ocean-floor and island-arc volcanic activity. This thesis studies the stratigraphy, distribution, geochronology, and petrology of these volcanic rocks, providing insights into Late Precambrian crustal evolution in NE Africa and Arabia. A three-fold stratigraphy is preserved in the basement of the CED. A section of oceanic crust is basal. These Older Metavolcanics (OMV) are conformably overlain by Immature Metasediments (IM). The IM are dominated by volcanogenic wackes and breccias, with subordinate hematitic Fe-formation and jasper, marls, and conglomerates derived from older sial. The IM are conformably succeeded by calc-alkaline Younger Metavolcanics (YMV). OMV, IM, and YMV are restricted to the Central Eastern Desert, but analogous terranes are found in N. Arabia. The YMV and associated plutons are dated by Rb/Sr techniques. The CED is the youngest crustal domain in the Egyptian basement, being flanked by older Proterozoic crust to the north and south and by the Archean Saharan Craton to the west. The data show that an intense episode of instability, convection, and widespread melting occurred in the mantle beneath Afro-Arabia at the end of the Precambrian. A model is presented whereby NE Gondwanaland was rifted, 650-620 mya, along a N-S trend to form a Late Proterozoic proto-Red Sea. This basin was closed by reconvergence of the Saharan and E. Arabian cratons at about 620-600 mya.},
doi = {},
url = {https://www.osti.gov/biblio/5473392}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 1979},
month = {Mon Jan 01 00:00:00 EST 1979}
}

Thesis/Dissertation:
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