scholarly journals Geology, geochemistry and tectonic setting of Pan-African serpentinites of Um Salim-Um Salatit area, Central Eastern Desert, Egypt

2012 ◽  
Vol 15 (2) ◽  
pp. 171-184 ◽  
Author(s):  
A.K.A. Salem ◽  
A.E. Khalil ◽  
T.M. Ramadan
Keyword(s):  
Tectonic Setting ◽  
Eastern Desert ◽  
Central Eastern Desert ◽  
Pan African ◽  
Central Eastern

scholarly journals Geochemistry of the Um Had Plutonites, Central Eastern Desert, Egypt: Implications for Magma Evolution, and Tectonic Setting

2014 ◽  
Vol 6 (2) ◽  
pp. 36 ◽  
Author(s):  
Nedal Qaoud
Keyword(s):  
Tectonic Setting ◽  
Active Continental Margin ◽  
Eastern Desert ◽  
Island Arc ◽  
Water Vapour Pressure ◽  
Calc Alkaline ◽  
Magma Evolution ◽  
Basement Complex ◽  
Central Eastern Desert ◽  
Pan African

Geochemistry of gabbroid and granitoid plutonites from the Um Had area indicates island arc subalkaline basic magma with tholeiitic affinity and calc-alkaline, metaluminous and slightly peraluminous magma, respectively. Although different in age both plutonite types were emplaced under compressional regime, where subduction-related environment was dominant. They were formed under relatively low to moderate water-vapour pressure (1–5 k-bars) at moderate depths (20–30 km). Biotite granites were formed at a relatively high temperature range (800–840 °C), while biotite-muscovite granites were formed under relatively moderate temperature conditions (760–800 °C). These two units may represent evolution from island arc to active continental margin. It is suggested that island arc gabbros might have sourced the late subduction-related calc-alkaline granitoids during the waning stages of the pan-African orogeny. The I-type nature of the investigated plutonites in the study area and elsewhere suggests the juvenile character of the basement complex of the Eastern Desert of Egypt.

scholarly journals Geological and geochemical studies on El-Missikat granites, Central Eastern Desert, Egypt

2020 ◽  
pp. 7-18
Author(s):  
Ibrahim m ABU EL-LEIL ALI ◽  
◽  
Abdellah Sadek TOLBA ◽  
Hamdy Ahmed Mohamed AWAD ◽  
Aleksey Valer’evich NASTAVKIN ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Eastern Desert ◽  
Quartz Diorite ◽  
Granitic Rocks ◽  
Nile Valley ◽  
Thin Sections ◽  
Central Eastern Desert ◽  
Different Types ◽  
Central Eastern ◽  
Geochemical Studies

Objective. The present work deals with the detailed investigations of the geology, geochemistry, and tectonic setting of the studied granitic rocks. Research methods. This work involves 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), Atomic absorption, X-ray Fluorescence analysis (XRF) in the Central Laboratories of the Acme in Canada and Mass-Spectrometer with Inductively Coupled Plasma (ICPMS). Result. The study area restricted in the Central Eastern Desert of Egypt between the Red sea and the Nile Valley. ElMissikat pluton is covered by island arc related rock (as xenolith), older granites, and younger granites, in addition to different types of dikes and veins swarms. Petrographically older granites are classified into quartz diorite, tonalite and granodiorite, whereas the younger granites are divided into monzogranite, syenogranite and altered granites. The geochemical studies suggest the granitic rocks are calc-alkaline affinity. The quartz diorite, tonalite and granodiorite are related to volcanic arc granites, while the monzogranite and syenogranite are similar to the infinity of the within plate granites behavior. The quartz diorite, tonalite, granodiorite and monzogranite are belonging to I-type granite, otherwise the syenogranite has A-type granites. Conclusion. According to geological and petrographical studies the investigated granites are represented by quartz diorite, tonalite and granodiorite, whereas the younger granites are divided into monzogranite, syenogranite and altered granites that are traversed by different types of dikes and veins swarms . Generally, the older granites have low content of LILE, most probably due to the relatively low content of K-feldspars and HFSE. The younger granites exhibit a fractionated pattern from LREE to HREE with negative Eu anomaly.

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