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Geological studies and structural analysis of the Umm Anab metavolcanics and related quartz veins: implications for Pan-African volcanism in the Egyptian Nubian Shield

Article

Last updated: 28 Dec 2024

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Abstract

The Neoproterozoic basement complex of the Umm Anab area is located 40 km southwest of Hurghada city in the Northern Eastern Desert (NED) of Egypt. The basement rocks include metavolcanics and enormous plutons of granitoid rocks. The metavolcanics are regionally metamorphosed, forming greenschist to amphibolite facies rocks interbedded with banded iron formation (BIF).
Structural analysis in the Umm Anab metavolcanics (UAV) indicates that the area has a poly-phase structural deformation, and each phase has its own effect and style. A Well-developed schistosity striking approximately E-W with dipping 60º-80º southward, and asymmetrical folds with oblique subvertical NNW-striking axial planes were observed. The structural analysis of the veins in metavolcanic by using GArcmB software determined the paleostress inversion and displayed two clusters of veins that formed under two stresses. The stress ratios (Φ)= (σ2 – σ3) / (σ1 – σ3) for both clusters, respectively, are ~0.39 and ~0.16, which shows two stress status. The values of the stress ratio on vein walls suggest that the host rock was subject to low to moderate tectonic stress at the time the veins formation. In addition, finite strain results in metavolcanics were estimated using the Rf/φ method on deformed pebbles (with a trend of N73º-88ºE), confirming the idea that metavolcanics are affected by low to moderate deformation. The stretching mineral lineation and BIF have trend ENE-WSW to E-W that supports the oldest shortening event (D1) which is considered an early phase of deformation NNW–SSE linked with the Pan-African thrusting.

DOI

10.21608/egjg.2023.228339.1056

Keywords

Umm Anab, Metavolcanics, Strain analysis, Deformation phases, Egypt, Northeastern Desert

Authors

First Name

Khaled

Last Name

El-Gameel

MiddleName

-

Affiliation

Geology Department, Faculty of Science, Menoufia University

Email

khaled.elgamel@science.menofia.edu.eg

City

Sheben El-Kom

Orcid

0000-0003-2542-4400

First Name

Sara

Last Name

Fayed

MiddleName

-

Affiliation

Geology Department, Faculty of Science, Menoufia University

Email

sarajooo22@gmail.com

City

Sheben El-Kom

Orcid

-

First Name

Hamdy

Last Name

El Desouky

MiddleName

-

Affiliation

Geology Department, Faculty of Science, Menoufia University

Email

geohamdy@yahoo.com

City

Sheben El-Kom

Orcid

-

First Name

Ashraf

Last Name

Abdelmaksoud

MiddleName

-

Affiliation

Geology Department, Faculty of Science, Menoufia University

Email

ashraf_sobhy2001@yahoo.com

City

Sheben El-Kom

Orcid

-

Volume

67

Article Issue

1

Related Issue

40290

Issue Date

2023-12-01

Receive Date

2023-08-11

Publish Date

2023-12-01

Page Start

243

Page End

259

Print ISSN

0022-1384

Online ISSN

2805-2617

Link

https://egjg.journals.ekb.eg/article_316215.html

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https://egjg.journals.ekb.eg/service?article_code=316215

Order

14

Type

Original Article

Type Code

2,013

Publication Type

Journal

Publication Title

Egyptian Journal of Geology

Publication Link

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

MainTitle

Geological studies and structural analysis of the Umm Anab metavolcanics and related quartz veins: implications for Pan-African volcanism in the Egyptian Nubian Shield

Details

Type

Article

Created At

28 Dec 2024