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The Neoproterozoic litho-units (e.g. ophiolites and ophiolitic mélange, arc metavolcanics, syn-tectonic granitoids, volcanosedimentary sequences, and late- to post tectonic and post-collisional intrusions) outcropping at the Egyptian Eastern Desert and Sinai are collectively known as the Egyptian Nubian Shield (ENS). The ENS covers vast portion (~ 105 km2) of the Arabian-Nubian Shield (ANS) in NE Africa. The ENS and the entire ANS represent the upper crustal equivalent of the high-grade Mozambique Belt in the East African Orogen (EAO) which is regarded to be formed by the collision of East and West Gondwanalands. General agreement exists that the ENS (and the ANS) evolved during three successive Neoproterozoic events; intra-oceanic subduction and arc accretion event, orogenic compressional event, and post-compressional extensional event. Several attempts have been made by many workers to decipher these Neoproterozoic crustal events because of their relations to metallic georesources, particularly gold deposits. Understanding these events offers a superb opportunity to explore the scheme of structural/tectonic events and their relations to the magmatic-metamorphic ones, as well as the relation between juvenile and evolved magmas, and the processes of crust-mangle connections. The present chapter briefly outlines the tectonic evolution and the regional geology of the ENS in an attempt to build a general frame for the upcoming chapters of this book, which address gold deposits in the ENS in terms of geology, settings, types, genesis, and spatiotemporal distribution. Following the introduction, a brief description of the rock succession dominating at the ENS is given. The regional geology and temporal evolution of the ENS are discussed in the time-line frame presenting the evolutionary stages; island arc, and syn- to post-accretionary stage. A particular consideration is given to the structural framework and related features (e.g. transpressional and extensional shearing, thrusting, folding and alterations) attributed to these stages.

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Brief Note on the Geology and Tectonics of the Egyptian Nubian Shield

  • 章节

  • 发表日期：

    2025年

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  • Zakaria Hamimi,
  • Yasser Abd El-Rahman,
  • Harald Fritz

摘要

The Neoproterozoic litho-units (e.g. ophiolites and ophiolitic mélange, arc metavolcanics, syn-tectonic granitoids, volcanosedimentary sequences, and late- to post tectonic and post-collisional intrusions) outcropping at the Egyptian Eastern Desert and Sinai are collectively known as the Egyptian Nubian Shield (ENS). The ENS covers vast portion (~ 105 km2) of the Arabian-Nubian Shield (ANS) in NE Africa. The ENS and the entire ANS represent the upper crustal equivalent of the high-grade Mozambique Belt in the East African Orogen (EAO) which is regarded to be formed by the collision of East and West Gondwanalands. General agreement exists that the ENS (and the ANS) evolved during three successive Neoproterozoic events; intra-oceanic subduction and arc accretion event, orogenic compressional event, and post-compressional extensional event. Several attempts have been made by many workers to decipher these Neoproterozoic crustal events because of their relations to metallic georesources, particularly gold deposits. Understanding these events offers a superb opportunity to explore the scheme of structural/tectonic events and their relations to the magmatic-metamorphic ones, as well as the relation between juvenile and evolved magmas, and the processes of crust-mangle connections. The present chapter briefly outlines the tectonic evolution and the regional geology of the ENS in an attempt to build a general frame for the upcoming chapters of this book, which address gold deposits in the ENS in terms of geology, settings, types, genesis, and spatiotemporal distribution. Following the introduction, a brief description of the rock succession dominating at the ENS is given. The regional geology and temporal evolution of the ENS are discussed in the time-line frame presenting the evolutionary stages; island arc, and syn- to post-accretionary stage. A particular consideration is given to the structural framework and related features (e.g. transpressional and extensional shearing, thrusting, folding and alterations) attributed to these stages.