Answers are grounded in this paper and cite their sources.
Observational analysis describes mineralization types and basin evolution in the Malayer-Esfahan Metallogenic Belt, suggesting insights for future exploration.
The Malayer-Esfahan Metallogenic Belt (MEMB) is one of the largest undeveloped Zn-Pb belts in the world. The Jurassic-Lower Cretaceous sedimentary-(volcanic) rocks in the MEMB contain stratiform and stratabound Zn-Pb (±Ba±Ag), Fe-Mn-Pb (±Ba±Cu) and Ba mineralizations. This article provides a summary of the highlights of the MEMB deposits and discusses about the type of mineralization, structural evaluation, and important mineralization controls, based on geological observations and previous literature. The ore deposits of the MEMB occur in local basins that evolved in a back-arc tectonic setting. The sedimentary and volcanic layers of these basins were deposited in three phases. These phases are: syn-rift, transition from syn-rift to sag-phase, and sag-phase deposition. The syn-rift sequence includes of all Jurassic rocks deposited in a fault-bounded extensional basin. Syn-rift sequences are overlain by shallow marine mudstones, carbonates, volcanics, and sandstones that extend over the rifted areas alike, forming a transitional stage from syn-rift phase to sag-phase sequence. The largest volume of volcanic and volcanoclastic rocks in the MEMB basin was formed during this stage. Kc 1 , Kc 2 and Kcv units of the Lower Cretaceous sequences related to the transitional phase. In the MEMB, sag-phase sediments (Km, Kl, Klsd and Ku units) have been repeated in several stages, and this phenomenon has led to the formation of numerous mineralizations in several ore-bearing horizons at this stage of the MEMB evolution. Nine major mining districts have been identified in the MEMB, with the main deposits located in Jurassic rocks and the Kc, Kl and Ks units of Lower Cretaceous sequence. Ore mineralizations occur in two different processes: (1) as exhalative ores (SEDEX and hybrid SEDEX-VMS) in seafloor brines, (2) as subseafloor replacement mineralizations in the SEDEX (or Irish) style. The exhalative ores in shale, sandstone and volcanic rocks are located southeast of Malayer, south of Arak, northwest of Golpayegan, Aligoudarz, and south of Shahreza mining districts. Most of these deposits were formed during the Jurassic period and in the Kc 2 , Kcv, Kc 2 , Kc 3, and Klsd units. Most of these deposits were formed in the syn-rift and transitional stages of basin evolution. The SEDEX (or Irish) subseafloor replacement deposits are limited to early permeable reaction layers in the Lower Cretaceous rocks, including carbonate and carbonate-siliciclastic rocks. The most important of this type deposits/occurrences are Irankuh, Shamsabad, Emarat, Robat, Khanabad, Anjireh, and Khaneh-Sormeh. These types of deposits are formed in the sedimentary sequence of sage-phase. The δ 34 S values of sulfide minerals in the MEMB deposits indicate that sulfur originates from seawater through thermochemical sulfate reduction (TSR) and bacteriogenic sulfate reduction (BSR). The δ 34 S values of barite in the MEMB deposits range extend from +10.3 to +32‰. This shows the sulfur in the mentioned deposits originates from Jurassic-Lower Cretaceous marine sulfate. Fluid inclusions studies in the MEMB deposits indicate that the ore-bearing fluids originated from basinal and marine waters with moderate to high temperature and moderate salinity. This paper presents a new regional geological model for the MEMB that provides a more detailed understanding of Zn-Pb (±Ba±Ag), Fe-Mn-Pb (±Ba±Cu) and Ba mineralizations, and is a new tool to expand the knowledge of SEDEX, hybrid of SEDEX to VMS, and subseafloor replacement mineralizations with carbonate host rocks, which can be an exploratory guide for future research in the MEMB.
No takes yet. Share an insight, caveat, or question.
Maghfouri et al. (2025) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: