Neoproterozoic arc sedimentation, metamorphism and collision: evidence from the northern tip of the Arabian-Nubian Shield and implication for the terminal collision between East and West Gondwana

Journal Publication ResearchOnline@JCU
Abu Sharib, Ahmed S.A.A.;Maurice, Ayman E.;Abd El-Rahman, Yasser M.;Sanislav, Ioan V.;Schulz, Bernhard;Bakhit, Bottros R.
Abstract

In the Wadi Um Had area, Central Eastern Desert, Egypt, NE-trending metapelitic and molasse-type successions are exposed. The metasediments bear the geochemical signature of a first depositional cycle in two distinct continental island arc settings that derived from incipiently-to moderately-weathered intermediate to felsic sources under generally warm and humid conditions. The metapelitic succession records three distinct episodes of metamorphism, M1–M3, whereas the molasse-type succession records only the last metamorphic episode, M3. M1/D1 records an amphibolite facies tectono-metamorphic event that has been dated at 625 ± 5 Ma, whereas M2/D2 records a greenschist facies subduction-related event. Collision of the two domains during a NE–SW shortening D3, culminated in formation of the macroscopic NW–SE-trending folds. D2 and D3 correlate with the gneiss-forming event, which is constrained at <609 Ma, and doming of the nearby Meatiq gneiss dome, respectively. M3 is a hornblende hornfels facies thermal metamorphism related to the intrusion of the post-orogenic, Neoproterozoic (596.3 Ma) Um Had granite. This study records, for the first time, a tectono-metamorphic phase predating the gneiss-forming event in the Meatiq gneiss dome, and pushes the boundary of the Late Ediacaran terminal collision between East and West Gondwana to ≤600 Ma.

Journal

Gondwana Research

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66

ISBN/ISSN

1342-937X

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Pages Count

30

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Publisher

Elsevier

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DOI

10.1016/j.gr.2018.09.004