Devonian/Lower Carboniferous stratigraphy, facies patterns and palaeogeography of Iran Part II. Northern and central Iran

Abstract

Apart from a few small remnants of the Turan Plate in the north, Iran during the Palaeozoic was part of the northern margin of Gondwana. On the basis of 65 sections, the majority of them covering the time-span from the Late Silurian into the Early Carboniferous, the stratigraphy and facies pattern of this area have been elucidated. Biostratigraphical calibration and correlation of the sections, mostly by means of conodonts and brachiopods, show the evolution from a shallow carbonate-dominated shelf in the Silurian which, by a drop of sea-level, was transformed into a siliciclastic shelf during the Early Devonian. Fully marine conditions were subsequently re-established in the Middle Devonian to early Frasnian and persisted into the early Late Carboniferous. A widespread uplift in the latest Carboniferous turned the entire area into a continental regime before the onset of a new marine cycle during the late Early Permian. With the exception of the northern zone (Talesh Range, Aghdarband), the Palaeozoic of Iran is characterized by continental to shallow marine deposits showing that enormous portions of the northern margin of this sector of Gondwana have been subducted during the convergence of the Turan and Iran Plates and the elimination of the Palaeotethys during the Late Triassic.