Oppositely dipping thrusts and transpressional imbricate zone in the Central Eastern Desert of Egypt

Abstract This paper documents the 40–60 km wide ENE–WSW trending Mubarak–Barramiya shear belt (MBSB) in the Central Eastern Desert of Egypt by examining its structural styles, kinematics and geometry. Our study revealed the existence of prevalent dextral and minor sinistral conjugate shear zones. The MBSB is metamorphic belt (greenschist–amphibolite) characterized by at least three post-collisional (740–540 Ma) ductile Neoproterozoic deformation events (D 1 , D 2 and D 3 ) followed by a brittle neotectonic deformation (D 4 ). D 1 event produced early top-to-the-northwest thrust displacements due to NW–SE shortening. D 2 produced discrete zones of NNW-trending upright folds and culminated in initiation of major NW-trending sinistral shear zones of the Najd Fault System (NFS, at c. 640–540 Ma ago) as well as steeply dipping S 2 foliation, and shallowly plunging L 2 lineation. NW-to NNW-trending F 2 folds are open to steep and vary in plunge from horizontal to vertical. D 2 deformational fabrics are strongly overprinted by D 3 penetrative structures. D 3 is characterized by a penetrative S 3 foliation, steeply SE- to NW-plunging and shallowly NE-plunging stretching lineations (L 3 ), asymmetric and sheath folds (F 3 ) consistent with dextral sense of movement exhibited by delta- and sigma-type porphyroclast systems and asymmetric boudinage fabrics. D 2 –D 3 represent a non-coaxial progressive event formed in a dextral NE- over NW-sinistral shear zone during a partitioned transpression in response to E–W-directed compression during oblique convergence between East and West Gondwana developed due to closure of the Mozambique Ocean and amalgamation of the Arabian–Nubian Shield in Cryogenian-early Ediacaran time.

[1]  G. Y. Boghdady,et al.  Structural constraints on the evolution of the Meatiq Gneiss Dome (Egypt), East-African Orogen , 2010 .

[2]  M. Azer,et al.  Supra-subduction affinity in the Neoproterozoic serpentinites in the Eastern Desert, Egypt: Evidence from mineral composition , 2007 .

[3]  F. B. Davies.  Strain Analysis of Wrench Faults and Collision Tectonics of the Arabian-Nubian Shield , 1984, The Journal of Geology.

[4]  Nagy Shawky Botros,et al.  A new classification of the gold deposits of Egypt , 2004 .

[5]  R. Greiling.  Thrust tectonics in crystalline domains: The origin of a gneiss dome , 1997, Journal of Earth System Science.

[6]  Cees W. Passchier,et al.  Porphyroclast systems as kinematic indicators , 1985 .

[7]  P. Johnson,et al.  NEOPROTEROZOIC OPHIOLITES IN THE ARABIAN SHIELD: FIELD RELATIONS AND STRUCTURE , 2004 .

[8]  A. Fowler,et al.  The significance of gneissic rocks and synmagmatic extensional ductile shear zones of the Barud area for the tectonics of the North Eastern Desert, Egypt , 2006 .

[9]  T. Kusky,et al.  Late Cryogenian-Ediacaran history of the Arabian-Nubian Shield: A review of depositional, plutonic, structural, and tectonic events in the closing stages of the northern East African Orogen , 2011 .

[10]  Basem Zoheir,et al.  Listvenite–lode association at the Barramiya gold mine, Eastern Desert, Egypt , 2011 .

[11]  A. Cruden,et al.  Strain and vorticity patterns in ideally ductile transpression zones , 1994 .

[12]  K. C. Nielsen,et al.  Orientation of late Precambrian sutures in the Arabian-Nubian shield , 1990 .

[13]  K. Khalil,et al.  Genesis of the gold mineralization at the Dungash gold mine area, Eastern Desert, Egypt: a mineralogical microchemical study , 2003 .

[14]  K. Khalil,et al.  Alteration Patterns Related to Hydrothermal Gold Mineralizaition in Meta‐andesites at Dungash Area, Eastern Desert, Egypt , 2001 .

[15]  E. S. Farahat,et al.  Neoproterozoic podiform chromitites in serpentinites of the Abu Meriewa–Hagar Dungash district, Eastern Desert, Egypt: Geotectonic implications and metamorphism , 2010 .

[16]  T. Kusky,et al.  Volcanosedimentary Basins in the Arabian-Nubian Shield: Markers of Repeated Exhumation and Denudation in a Neoproterozoic Accretionary Orogen , 2013, Geosciences.

[17]  Raymond E. Arvidson,et al.  Mapping of serpentinites in the Eastern Desert of Egypt by using Landsat thematic mapper data , 1986 .

[18]  A. Fowler,et al.  The Sha'it-Nugrus shear zone separating Central and South Eastern Deserts, Egypt: A post-arc collision low-angle normal ductile shear zone , 2009 .

[19]  S. Schmid,et al.  An evaluation of criteria to deduce the sense of movement in sheared rocks , 1983 .

[20]  Pär Weihed,et al.  Greenstone-hosted lode-gold mineralization at Dungash mine, Eastern Desert, Egypt , 2014 .

[21]  T. Kusky,et al.  Neoproterozoic nappes and superposed folding of the Itremo Group, west-central Madagascar , 2007 .

[22]  Basil Tikoff,et al.  Stretching lineations in transpressional shear zones: an example from the Sierra Nevada Batholith , 1997 .

[23]  P. Pitfield,et al.  Provenance and tectonic significance of the Palaeoproterozoic metasedimentary successions of central and northern Madagascar , 2011 .

[24]  G. Hoinkes,et al.  Continental back-arc basin origin of some ophiolites from the Eastern Desert of Egypt , 2004 .

[25]  S. Berhe.  Ophiolites in Northeast and East Africa: implications for Proterozoic crustal growth , 1990, Journal of the Geological Society.

[26]  J. Meert.  A synopsis of events related to the assembly of eastern Gondwana , 2003 .

[27]  T. Ramadan,et al.  Geology, geochemistry and tectonic setting of Pan-African serpentinites of Um Salim-Um Salatit area, Central Eastern Desert, Egypt , 2012 .

[28]  R. Machado,et al.  Shear structures in the Serra do Azeite shear zone, southeastern Brazil: Transtensional deformation during regional transpression in the central Mantiqueira province (Ribeira belt) , 2007 .

[29]  Mamdouh M. Abdeen,et al.  Structural evolution of the Neoproterozoic Western Allaqi–Heiani suture, southeastern Egypt , 2003 .

[30]  R. Greiling,et al.  A structural synthesis of the Proterozoic Arabian-Nubian Shield in Egypt , 1994 .

[31]  R. Agar.  The najd fault system revisited; a two-way strike-slip orogen in the saudi arabian shield , 1987 .

[32]  W. B. Harland.  Tectonic transpression in Caledonian Spitsbergen , 1971, Geological Magazine.

[33]  T. Kusky,et al.  Structural and remote sensing analysis of the Betsimisaraka Suture in northeastern Madagascar , 2009 .

[34]  Mohamed A. Abd El-Wahed,et al.  Pan-African dextral transpressive duplex and flower structure in the Central Eastern Desert of Egypt , 2010 .

[35]  A. Shalaby.  The northern dome of Wadi Hafafit culmination, Eastern Desert, Egypt: Structural setting in tectonic framework of a scissor-like wrench corridor , 2010 .

[36]  J Loizenbauer,et al.  Structural geology, single zircon ages and fluid inclusion studies of the Meatiq metamorphic core complex: Implications for Neoproterozoic tectonics in the Eastern Desert of Egypt , 2001 .

[37]  J. Moore.  Tectonics of the Najd Transcurrent Fault System, Saudi Arabia , 1979, Journal of the Geological Society.

[38]  A. Ries,et al.  Pan-African structures, ophiolites and mélange in the Eastem Desert of Egypt: a traverse at 26°N , 1983, Journal of the Geological Society.

[39]  M. El-Wahed,et al.  Synoblique convergent and extensional deformation and metamorphism in the Neoproterozoic rocks along Wadi Fatira shear zone, Northern Eastern Desert, Egypt , 2009 .

[40]  S. Kamh,et al.  Evolution of Strike-Slip Duplexes and Wrench-Related Folding in the Central Part of Al Jabal Al Akhdar, NE Libya , 2013, The Journal of Geology.

[41]  M. Abdelsalam.  The Oko Shear Zone, Sudan: post-accretionary deformation in the Arabian-Nubian Shield , 1994, Journal of the Geological Society.

[42]  B. E. Kalioubi,et al.  The Migif–Hafafit gneissic complex of the Egyptian Eastern Desert: fold interference patterns involving multiply deformed sheath folds , 2002 .

[43]  Robert J. Stern,et al.  Sutures and shear zones in the Arabian-Nubian Shield , 1996 .

[44]  D. Schultz-Ela,et al.  Transpression in an Archean greenstone belt, northern Minnesota , 1988 .

[45]  Mohamed A. Abd El-Wahed,et al.  Thrusting and transpressional shearing in the Pan-African nappe southwest El-Sibai core complex, Central Eastern Desert, Egypt , 2008 .

[46]  M. Hamdy,et al.  Multi-element association analysis of stream sediment geochemistry data for predicting gold deposits in Barramiya gold mine, Eastern Desert, Egypt , 2012 .

[47]  R. Stern.  ARC Assembly and Continental Collision in the Neoproterozoic East African Orogen: Implications for the Consolidation of Gondwanaland , 1994 .

[48]  F. Corfu,et al.  U–Pb TIMS age constraints on the evolution of the Neoproterozoic Meatiq Gneiss Dome, Eastern Desert, Egypt , 2009 .

[49]  P. Williams,et al.  High-strain zones: a unified model , 1998 .

[50]  Rushdi Said.  The Geology Of Egypt , 1962 .

[51]  D. Gray,et al.  Structure and strain variation at mid-crustal levels in a transpressional orogen: A review of Kaoko Belt structure and the character of West Gondwana amalgamation and dispersal , 2008 .

[52]  Basem Zoheir,et al.  Origin and Evolution of the Um Egat and Dungash Orogenic Gold Deposits, Egyptian Eastern Desert: Evidence from Fluid Inclusions in Quartz , 2008 .

[53]  G. Y. Boghdady,et al.  U–Pb ID-TIMS dating of igneous and metaigneous rocks from the El-Sibai area: time constraints on the tectonic evolution of the Central Eastern Desert, Egypt , 2011, International Journal of Earth Sciences.

[54]  H. Fritz,et al.  Neoproterozoic tectonothermal evolution of the Central Eastern Desert, Egypt: a slow velocity tectonic process of core complex exhumation , 2002 .

[55]  R. Stern.  Crustal evolution in the East African Orogen: a neodymium isotopic perspective , 2002 .

[56]  R. Greiling,et al.  On the tectonic evolution of the Wadi Hafafit area and environs, eastern desert of Egypt , 1982 .

[57]  T. Kusky,et al.  Cryogenian ophiolite tectonics and metallogeny of the Central Eastern Desert of Egypt , 2012 .

[58]  H. J. Beadnell.  The Geological Survey of Egypt , 1900, Geological Magazine.

[59]  A. Fowler,et al.  El Sibai gneissic complex, Central Eastern Desert, Egypt: Folded nappes and syn-kinematic gneissic granitoid sheets – not a core complex , 2007 .

[60]  T. Kusky,et al.  Orogen styles in the East African Orogen: A review of the Neoproterozoic to Cambrian tectonic evolution , 2013, Journal of African earth sciences.

[61]  V. Prasannakumar,et al.  Fabric evolution in Salem-Attur Shear Zone, South India, and its implications on the kinematics , 2009 .

[62]  H. Fritz,et al.  A late Neoproterozoic magmatic core complex in the Eastern Desert of Egypt: emplacement of granitoids in a wrench-tectonic setting , 2002 .

[63]  F. A. E. Ela.  Bimodal volcanism of the Igla Eliswid-Um Khariga metavolcanics, Eastern Desert, Egypt , 1992 .

[64]  T. Fowler,et al.  Gneiss-cored interference dome associated with two phases of late Pan-African thrusting in the Central Eastern Desert, Egypt , 2001 .

[65]  M. Whitehouse,et al.  Detrital zircon geochronology and provenance of the Neoproterozoic Hammamat Group (Igla Basin), Egypt and the Thalbah Group, NW Saudi Arabia : Implications for regional collision tectonics , 2014 .

[66]  R. Thomas,et al.  Geochronology of the Precambrian crust in the Mozambique belt in NE Mozambique, and implications for Gondwana assembly , 2009 .

[67]  Timothy M. Kusky,et al.  Precambrian ophiolites and related rocks , 2004 .

[68]  R. Stern.  The Najd Fault System, Saudi Arabia and Egypt: A Late Precambrian rift‐related transform system? , 1985 .

[69]  Timothy M. Kusky,et al.  Lithological mapping in the Eastern Desert of Egypt, the Barramiya area, using Landsat thematic mapper (TM) , 2006 .

[70]  C. Hauzenberger,et al.  Neoproterozoic calc‐alkaline peraluminous granitoids of the Deleihimmi pluton, Central Eastern Desert, Egypt: implications for transition from late‐ to post‐collisional tectonomagmatic evolution in the northern Arabian–Nubian Shield , 2011 .

[71]  M. El-Wahed.  The role of the Najd Fault System in the tectonic evolution of the Hammamat molasse sediments, Eastern Desert, Egypt , 2010 .

[72]  H. Fritz,et al.  The Wadi Mubarak belt, Eastern Desert of Egypt: a Neoproterozoic conjugate shear system in the Arabian-Nubian Shield , 2005 .

[73]  Mohamed W. Ali‐Bik,et al.  Serpentinite-hosted talc–magnesite deposits of Wadi Barramiya area, Eastern Desert, Egypt: Characteristics, petrogenesis and evolution , 2012 .

[74]  B. Yibas,et al.  NEOPROTEROZOIC OPHIOLITES OF THE ARABIAN-NUBIAN SHIELD , 2004 .

[75]  M. Abdeen,et al.  Syn- and post-accretionary structures in the Neoproterozoic Central Allaqi-Heiani suture zone, Southeastern Egypt , 2011 .

[76]  E. S. Farahat,et al.  Origin of I- and A-type granitoids from the Eastern Desert of Egypt: Implications for crustal growth in the northern Arabian Nubian Shield , 2007 .

[77]  M. Azer,et al.  Post-collisional magmatism in the northern Arabian-Nubian Shield: The geotectonic evolution of the alkaline suite at Gebel Tarbush area, south Sinai, Egypt , 2011 .

[78]  P. Johnson,et al.  Development of the Arabian-Nubian Shield: perspectives on accretion and deformation in the northern East African Orogen and the assembly of Gondwana , 2003, Geological Society, London, Special Publications.

[79]  H. Fritz,et al.  The Sukari Gold Mine, Eastern Desert—Egypt: structural setting, mineralogy and fluid inclusion study , 2004 .

[80]  F. F. A. El-Ela.  Geochemistry of an island-arc plutonic suite: Wadi Dabr intrusive complex, Eastern Desert, Egypt , 1997 .

[81]  H. Fritz,et al.  Formation of Neoproterozoic metamorphic complex during oblique convergence (Eastern Desert, Egypt) , 1996 .

[82]  N. Woodcock,et al.  Transpressive duplex and flower structure: Dent Fault System, NW England , 2003 .