Sedimentary and structural characteristics of the Paleo-Tethys remnants in northeastern Iran

Remnants of the Paleo-Tethys oceanic realm in the Binalood region of northeast Iran include not only ophiolite complexes but also a pile of upward-coarsening, pre-Late Triassic metasedimentary rocks that are here interpreted to be abyssal plain and deep-sea flysch deposits. The flysch succession consists of trench-fill turbidites and associated carbonate conglomerates and olistostromes, which, together with the ophiolites, constitute an accretionary complex formed in a trench-forearc environment over a tectonically active, north-dipping subduction zone. Structurally, the evolution of this oceanic assemblage involved south-verging thrust faulting of the accretionary-prism and abyssal-plain deposits, as well as their underlying oceanic crust, resulting in the formation of a stack of off-scraped thrust slivers that later, down in the subduction zone, underwent redeformation and greenschist metamorphism. Obduction of the accretionary assemblage over the Iranian microcontinent took place prior to Late Triassic time.