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216390

Petrography, Geochemistry and Radioactivity of Alkaline A-Type Granites and Associated Pegmatites from Gabal Um Guruf Region, North Eastern Desert, Egypt

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Last updated: 28 Dec 2024

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Abstract

The present study focuses on three granitic bodies from Gabal Um Guruf region in the North Eastern
Desert of Egypt. They comprise Gabal El Resha fine-grained granite, Gabal Homret El Sawrhiya mediumgrained
granite and Wadi El Misdar coarse-grained granite. They have nearly similar mineralogical
compositions and could be classified as alkali feldspar granites. However, the presence and proportions of
the accessory minerals show some variations among the three granitic bodies, causing observed changes in
their trace element compositions. Geochemically, these granites exhibit pronounced A-type affinity and
belong to the alkaline series. They have high concentrations of SiO2 and total alkalis, low abundances of
CaO, MgO and TiO2 and enrichment in some HFSE (Zr, Y and U). The granitic bodies show similar REE
patterns and spider diagrams with striking depletions in Ba, Sr, P, Eu, and Ti. The obtained geological,
petrographical, and geochemical data of the studied granites suggest close genetic relationships and it is
suggested that they were formed from single parent magma through its differentiation in post-orogenic
environment. The radiometric investigation indicates that Gabal Homret Al Sawrhiya granite and its
associated pegmatites have the highest levels of gamma-ray measurements in the study area. This granite
shows similar mineralogical and geochemical features with U-bearing granite in Egypt. It is enriched in
radioactive inclusions along with higher contents of zircon and fluorite, suggesting parallel enrichment of F
and HFSE, which extending toward the associated highly evolved pegmatites. Additionally, it displays
various forms of post-magmatic hydrothermal alterations, especially along faults and shear zones. One
radioactive anomaly was recorded in a pegmatite body in Gabal Homret El Sawrhiya granite. The
pegmatite hosts U-Th, Zr and REE showings along the contact between the host granite and the pegmatite.

DOI

10.21608/egjg.2018.216390

Keywords

Gabal Um Guruf, alkaline granites, A-type granites, radioactive pegmatites

Authors

First Name

Amr Abdel Aty

Last Name

Abdel Hamid

MiddleName

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Affiliation

Nuclear Materials Authority, P.O 530 Al Maadi, Cairo,Egypt.

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Volume

62

Article Issue

1

Related Issue

30528

Issue Date

2018-12-01

Receive Date

2022-01-30

Publish Date

2018-12-01

Page Start

283

Page End

297

Print ISSN

0022-1384

Online ISSN

2805-2617

Link

https://egjg.journals.ekb.eg/article_216390.html

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https://egjg.journals.ekb.eg/service?article_code=216390

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18

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Journal

Publication Title

Egyptian Journal of Geology

Publication Link

https://egjg.journals.ekb.eg/

MainTitle

Petrography, Geochemistry and Radioactivity of Alkaline A-Type Granites and Associated Pegmatites from Gabal Um Guruf Region, North Eastern Desert, Egypt

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Article

Created At

23 Jan 2023