Metallogeny of Permian-Triassic carbonate-hosted Zn-Pb and F deposits of Iran: A review for future mineral exploration

There are more than 300 sediment-hosted ZnPb deposits and occurrences in Iran and most of them occur within carbonate rocks, including world-class deposits such as Mehdiabad, Irankuh and Angouran. To achieve a broad metallogenetic framework for carbonate-hosted (CH) ZnPb resources in Iran, we developed a GIS database with all reported deposits and occurrences of this affinity. From this database and the age of host rocks, two major groups of CH ZnPb deposits can be established and linked to different tectonic events: (a) PermianTriassic-hosted deposits (mainly of the Mississippi Valley-type; MVT), and (b) Cretaceous-hosted deposits. The PermianTriassic-hosted deposits are concentrated in the Central Alborz metallogenic belt, the NE margin of SanandajSirjan Zone (SSZ), and the Tabas-Posht e Badam metallogenic belt, whereas those hosted by Cretaceous carbonate rocks are distributed in the SSZ, the Yazd Block and the Central Iranian Geological and Structural (CIGS) transitional zone. In addition, the formation of numerous F-rich deposits hosted by PermianTriassic carbonate rocks is also explained by a MVT deposit model. According to our GIS-based metallogenic maps, there is a significant correspondence between the distribution of CH ZnPb deposits and the main suture zones in and around the Iran Plate. Most of the orogenic PermianTriassic-hosted MVT deposits occur along the suture zones that resulted from the collision of the Iran Plate with the Eurasia Plate when the Paleo-Tethys Ocean closed (during Upper Triassic time). The close spatial, temporal and (therefore assumed) genetic relationships between the PermianTriassic-hosted MVT deposits and the Main-Cimmerian orogenic events reflect the development of a foreland basin during the Upper Triassic, which encompassed ZnPb and F mineralising processes. The modern distribution of these deposits in Iran is explained by the formation of this foreland basin, and by the subsequent (post-Upper Triassic) fragmentation of the Central Iranian Microcontinent into blocks that rotated along right-lateral strike-slip faults. This late process split the PermianTriassic-hosted MVT province into the Tabas-Posht e Badam and the Central Alborz metallogenic belts.