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" The sedimentary evolution of the Suez rift basin, Egypt: "
A. L. Evans
S. A. Graham
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Latin Dissertation
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English
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| Record Number
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1112428
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TLpq303794364
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| Main Entry
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A. L. Evans
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S. A. Graham
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| Title & Author
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The sedimentary evolution of the Suez rift basin, Egypt:\ A. L. EvansS. A. Graham
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| College
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Stanford University
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| Date
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1989
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| student score
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1989
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| Degree
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Ph.D.
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| Page No
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239
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| Abstract
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The Suez rift is a northern extension of the Red Sea and separates the African plate from the Sinai microplate. Up to 5 km of Neogene (syn-rift) rocks were deposited along the rift axis, parallel to denuded rift flanks that have been uplifted 2-4 km since 20 Ma. The goal of this dissertation has been to detail the chronology and nature of rift tectonics in the Suez basin through the integrated study of the syn-rift sedimentary sequence. The methodology encompassed in this basin analysis included both field and laboratory study. Specific investigations included the micropaleontological dating of the lower and middle Miocene deposits (Nukhul, Rudeis, Kareem and Belayim Formations), the petrographic study of Miocene sandstone provenance relations, Rock-Eval pyrolysis, foraminiferal paleoecology and subsidence history analyses. Excellent biostratigraphic data were extracted from the marine portions of the Miocene sequence, from which formation ages and the chronostratigraphy of the basin were interpreted. The ages of the entire Miocene section were correlated with global nannofossil and planktonic foraminiferal zonations. This dating scheme was then integrated with results of the other analyses to interpret: uproofing and uplift history of the rift flanks; provenance relations of the kerogens in the Rudeis, Kareem and Belayim Formations; and to define a paleobathymetric model for the basin, based on benthic foraminiferal biofacies. These analyses show that extension commenced in late Oligocene to earliest Miocene, but the main rift event began 5 M.Y. later, at 19 Ma. The main rift event caused rapid tectonic subsidence of the entire basin prior to deposition of the Rudies Formation. Intense subsidence in the axial trough of the rift at 19 Ma also corresponds to the initiation of uplift of the rift flanks, at 20-18 Ma. Uplift of the rift flanks and margins narrowed the marine portion of the rift and exposed much of the modern onshore areas between 14 and 10 Ma. Following the initiation of sinistral motion along the Dead Sea-Aqaba transform at 15 Ma, the Suez rift was effectively decoupled from the Red Sea. Extension and tectonic subsidence in the Suez rift slowed markedly, while uplift of the flanks continues today.
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Earth sciences
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Geology
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