Structural and tectonic evolution of the Neoproterozoic Feiran–Solaf metamorphic belt, Sinai Peninsula: implications for the closure of the Mozambique Ocean

The Feiran–Solaf metamorphic belt of the southern Sinai Peninsula consists predominantly of amphibolite facies metapelitic, arenaceous, and minor calcareous rocks deformed during Neoproterozoic (850–550Ma) orogenesis and intruded by dioritic–tonalitic–granitic plutons. The belt is divided into the Solaf Zone in the southeast and the Feiran Zone in the northwest. Twenty-five detailed structural cross-strike transects reveal that intense polyphase deformation resulted in complex fold geometries and fabric relationships. On outcrop scale, the progressive D1 deformation is recognized as early, NW-striking, intrafolial isoclinal folds (F1), an associated steeply dipping gneissic (S1) fabric, and the development of calc-mylonite zones along the NE margin of the belt. Tight, NW-striking, recumbent similar folds (F2) characterize the late D1 deformation, whereas NE-striking open (F3) folds represent D2. Macro-scale folds of the F1 and F2 account for the map-scale structural pattern shown by the lithologic units. F3 is represented mostly by meso-scale folds. The early SE- and NW-plunging F1 and F2 fold axes may be related to accretion of intraoceanic sediments deposited between arcs and/or microcontinents, whereas the late NE-trending upright F3 folds may be related to post-accretionary tectonic events. In particular, the F3 folds and associated mineral stretching lineations, which trend NW–SE, may be related to the Najd fault system.