scholarly journals Microstructural finite strain analysis of the Hafafit granitoids domes South Central Eastern desert of Egypt

2017 ◽  
Vol 47 (2) ◽  
pp. 667 ◽  
Author(s):  
I. Thabet ◽  
A. Kilias ◽  
S. Kamh

The Wadi Hafafit Culmination (WHC) can be subdivided into two main units which are separated by Nugrus thrust shear zone. The WHC domes are occupies the southern part of the Central Eastern Desert of Egypt and is cored by five separated gneissic granitoids ranging in composition from tonalite to granodiorite having compositions consistent with hydrous partial melting of a mafic source suggesting subduction-related magmatism. The leucogranites along thrust zones is related to the late phase of metamorphism of Hafafit rocks. The five main domes of the WHC have been labeled A dome occupies the northern part of WHC, B and C domes occupies the central eastern part of WHC, D dome occupies the central western part of WHC and E dome occupies the southern part of WHC. The fourth domes A, B, C and E are affected by more than one deformation event but D dome is affected by one deformation event. The domes not uniform throughout the WHC according radial pattern of stretching lineation but these domes of WHC were subjected and affected by late-orogenic extension that was controlled by the Najd transform faults and that resulted in exhumation of the WHC domes are oriented NW-SE parallel to the trend of the left-lateral shear zones of Najd fault system.

Author(s):  
AWAD Hamdy Ahmed Mohamed ◽  
◽  
ALI Ibrahim Abu El-Leil ◽  
NASTAVKIN Aleksey Valer’evich ◽  
TOLBA Abdellah Sadek ◽  
...  

Objective. The current study aims to detect the geologic features, geochemical characteristics and tectonic setting of the investigated rock using field observations and geochemical analyses. Research methods. This work contains both field work (Collection samples and drawing of a new geological map) and laboratory work (preparation of thin sections for petrographic studies by polarizing microscope), X-ray Fluorescence analysis (XRF) in Institute of Biology, Southern Federal University and Mass-Spectrometer with Inductively Coupled Plasma (ICPMS) at the central Laboratory of Russian Geological Institute. Result. Investigated andesitic rock belongs to Dokhan volcanic that located in the Central Eastern Desert of Egypt a long Qena-Safaga Road. It is considered as one of the most important shear zones in Eastern Desert that includes distinctive rocks and economic mineral deposits. The investigated rock belongs to late to post tectonic magmatism of the East African Orogeny (EAO). Petrographically: Dokhan volcanic is represented by andesite according to petrographical studies. It consists of plagioclase, quartz, in addition to mafic minerals. Geochemically, the investigated andesite samples plotted in calk-alkaline nature. Conclusion. Tectonically, andesite samples fall in arc lava and continental fields. They are enriched in Ba, Sr, Rb, K, Nb and Ce with marked depletion in the most HFSEs like those of island arc calc-alkaline series.


2019 ◽  
Author(s):  
Ahmed Abdelaal ◽  
◽  
Mohamed Sultan ◽  
R.V. Krishnamurthy ◽  
Mustafa Kemal Emil ◽  
...  

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