Neoproterozoic arc sedimentation, metamorphism and collision: Evidence from the northern tip of the Arabian-Nubian Shield and implication for the terminal collision between East and West Gondwana

Sharib, A. S. A. A. Abu; Maurice, Ayman E.; El‐Rahman, Yasser Abd; Sanislav, Ioan V.; Schulz, Bernhard; Bakhit, Bottros R.

doi:10.1016/j.gr.2018.09.004

Cited by 17 publications

(4 citation statements)

References 105 publications

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“…D2 was the main contributing phase in the formation of the Meatiq dome. In this stage, the deformation has been switched to a nearly NE-SE shortening probably associated with the terminal oblique collision of East-and West-Gondwana at about 600 Ma (Abu Sharib et al, 2019;Mohammad et al, 2020). This phase involved the formation of the map-scale NWtrending folds and NW-SE striking thrust faults in Meatiq dome.…”

Section: Spatio-temporal Evolution Of Pluton Geometrymentioning

confidence: 99%

Geometry and growth of syn-tectonic plutons emplaced in thrust shear zones: Insights from Abu Ziran Pluton, Egypt

Mohammad¹,

Kazzaz²

2022

Preprint

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Coupling of deformation and magmatism has been reported in several old orogenic belts, particularly along thrust faults and shear zones. The syn-kinematic plutons in exhumed shear zones offer the best opportunity to understand the complex relationship between magmatism and regional deformation. The present paper investigates the geometry and internal structure of granite plutons emplaced in thrust faults and shear zones, and structural control on their emplacement mechanism. Abu Ziran pluton is an example of the intrusions emplaced in active brittle-ductile zones in the Nubian shield, and documents clear evidence on the interaction between magmatism and regional deformation during melt ascent and emplacement. Results from detailed geological mapping, remote sensing, and structural analysis of the pluton and associated highly strained rocks permitted the constraining of the pluton's geometry, emplacement mechanism, and spatio-temporal evolution. Structural analysis of the study area indicates that pluton emplacement was syn- to-late-tectonic. The brittle-ductile fabrics in the wall rock are consistent with a sub-horizontal thrust shear zone with a top-to-NW shear sense. The activity of the shear zone was accompanied by an episode of a calc-alkaline magmatic pulse. Granitic magma ascended upward via non-exposed feeder dykes, or through ramps and flats in the thrust system and emplaced laterally along the shear zone, forming complex sub-horizontal sheet-shaped intrusion. The geometry and extent of pluton emphasize that inherited heterogeneities and regional stress states played important role in the emplacement processes. In addition, localization of pluton along or near the contact between ophiolitic nappes and mylonitic metasediments suggests that the rheological boundaries act as barriers that impedes the rise of ascending magma, causing magma arrest, and triggers lateral spreading and emplacement. The outcomes of this study allowed the reconstruction of the geometry and internal structure of Abu Ziran pluton and an understanding of its evolution in space and time.

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Section: Spatio-temporal Evolution Of Pluton Geometrymentioning

confidence: 99%

Geometry and growth of syn-tectonic plutons emplaced in thrust shear zones: Insights from Abu Ziran Pluton, Egypt

Mohammad¹,

Kazzaz²

2022

Preprint

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“…The gneisses at Meatiq in the ENS give Rb-Sr and U-Pb zircon ages of 600-750 Ma (Lié geois and . Abu Sharib et al (2018) interpreted for the first time a tectono-metamorphic phase predating the gneiss-forming event in the Meatiq gneiss d o m e , p u s h i n g t h e b o u n d a r y o f t h e Late Ediacaran terminal collision between East and West Gondwana to ≤ 600 Ma.…”

Section: High-grade Gneisses and Migmatitesmentioning

confidence: 99%

Neoproterozoic Tectonic Events of Egypt

El‐Wahed

Hamimi

2021

Acta Geologica Sinica (Eng)

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The Egyptian Nubian Shield (ENS) represents the northwestern part of the Arabian‐Nubian Shield and the northern extension of the East African Orogen. The ENS is regarded as being formed due to northward‐directed escape tectonics. It is characterized by mild accretion and suture zones dominated by major strike‐slip zones with a commonly sinistral sense of movement; some shear zones display a dextral sense of shear. It is dominated by gneisses and migmatites in the south, arc volcaniclastic metasediments and highly dismembered ophiolites in the central parts, whereas its northern part is dominated by late‐ to post‐tectonic granitoids. In southern Sinai, the Neoproterozoic rocks are grouped into four complexes, namely Feiran–Solaf, Sa'al–Zaghra, Kid and Taba. The ENS ophiolites were formed between 730–750 Ma, mainly in a supra‐subduction zone setting. The ENS has undergone a Neoproterozoic deformation history involving three successive phases: (1) Early N–S shortening phase (D1), (2) Syn‐accretionary phase (D2) and (3) Post‐accretionary phase (D3). The initial island‐arc stage (780–730 Ma) is a N–S shortening phase initiated by collision between the Eastern Desert tectonic terrane to the north with both the Gebeit and Gabgaba terranes to the south (830–720 Ma). During the arc‐splitting and back‐arc spreading stage (730–620), voluminous syn‐tectonic granitoids intruded into the ENS (750–610 Ma). The E–W‐directed compressional/transpressional phase (620–450 Ma) led to the overall uplift of the central part of the ENS and consequently the development and exhumation of the core complexes in oblique convergent zones. The E–W intense shortening deformation resulted also in the formation of NW‐ and NE‐striking sinistral and dextral strike‐slip shear zones, respectively. The latest periods of the E–W‐directed compressional/transpressional regime were characterized by deposition of the molasse‐type Hammamat Sediments unconformably over the Dokhan Volcanics, or interbedded with them. The combined thrusting, folding and sinistral‐reverse shearing structures have been interpreted to resulted from the E–W‐directed compressional/transpressional phase in response to the oblique shortening of the Arabian‐Nubian Shield between East and West Gondwana.

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“…2c) is characterized by the collision of two or more continental landmasses. Continental collision, sometimes referred to as "terminal collision" in the literature (e.g., Najman et al, 2017;Abu Sharib et al, 2019), is characterized by a pre-collisional history that can involve a lengthy period of subduction and terrane accretion (cf., Types I and II). Because of the crustal thickness of the subducting lithosphere and its positive buoyancy, most of the incoming material cannot be subducted, or remain subducted, leading to crustal shortening, accommodated by low-angle syn-metamorphic ductile shearing and orogeny.…”

Section: A Four-fold Geodynamic Classification Of Orogensmentioning

confidence: 99%

Temporal and spatial evolution of orogens: a guide for geological mapping

François¹,

Pubellier

Robert

et al. 2022

Episodes

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Orogens develop in convergent settings involving two or more continental and/or oceanic plates. They are traditionally defined as zones of crustal deformation associated with mountain building resulting from either accretion of a terrane and/or an arc, continent-continent collision or rift-inversion. However, this definition does not consider the genetic link between an oceanic domain and an intracontinental rift, even though extension associated with a scissor-shape opening can be demonstrated in many oceanfloored basins. Consequently, we propose a new concept of orogenic evolution based on the development of extensional margins subsequently subjected to crustal shortening. Thus orogens that develop as a result of the closure of wide basins, are distinguished from mountain belts developed above subduction zones or that result from continental collision and inverted intra-continental rifts. Our review of several key orogens identifies similarities and differences in geodynamic processes through geological time including prior to the onset of plate tectonics ca. 2.5 Ga. We propose that mapping based on comparative tectonics is a good way to constrain such an evolution, and that this can start with a global-scale map of past-to-modern orogens aimed at re-exploring mountain building concepts spatially and temporarily. This is the primary objective of IGCP 667 project "World Map of Orogens".

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Neoproterozoic arc sedimentation, metamorphism and collision: Evidence from the northern tip of the Arabian-Nubian Shield and implication for the terminal collision between East and West Gondwana

Cited by 17 publications

References 105 publications

Geometry and growth of syn-tectonic plutons emplaced in thrust shear zones: Insights from Abu Ziran Pluton, Egypt

Geometry and growth of syn-tectonic plutons emplaced in thrust shear zones: Insights from Abu Ziran Pluton, Egypt

Neoproterozoic Tectonic Events of Egypt

Temporal and spatial evolution of orogens: a guide for geological mapping

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