Palaeogeographic and geodynamic control on the Iranian karst-type bauxite deposits

Abstract

The Iranian karst bauxite deposits formed in northwestern Iran, the Alborz Mountain Chain, Central Iranian Plateau, and Zagros Simply Folded Belt during warm periods of the middle–late Permian, Permo–Triassic, middle–late Triassic, late Triassic–early Jurassic, and late Cretaceous. According to the literature, mafic igneous and argillaceous carbonate rocks have been considered to be a source rock for these deposits. We show here that, according to palaeogeographic reconstructions, bauxite deposits are directly linked to the tectonic settings of the Iranian area through time. From the middle–late Permian to the late Triassic, the formation of the Iranian karst bauxite deposits coincides with the uplift of the rift and passive margin shoulders, and their disappearance through the subsequent thermal subsidence and sea-level rise. The occurrence of bauxite deposits in the late Cretaceous is coeval with relief formation associated with the arc–continent collision and obduction of the Semail plate with the Arabian margin. The present study supports the idea that palaeogeographic reconstructions can potentially be used as predictive tools for the possible occurrence of bauxites elsewhere in time slices when climatic prerequisites of bauxite formation prevailed.