Posht-e-Badam Metallogenic Block (Central Iran): A suitable zone for REE mineralization

Abstract

One of the most important ores for REE mineralization are iron oxide-apatite (IOA) deposits. The Posht-e-Badam Block (PBB) is a part of the Central Iranian geostructural zone which is the host of most important Fe deposits of Iran. Exploration studies of the IOA deposits within the PBB (e.g. Esphordi, Gazestan, Zarigan, Lak-e-Siah, Sechahoun, Chahgaz, Mishdovan, Cheshmeh Firouzi and Shekarab) demonstrate that these deposits contain high contents of REE. Concentrations of ∑REE in the most important IOA deposits of the PBB include the following: the Esphordi deposit varies between 1.2 and 1.88%, the Gazestan deposit between 0.17 and 1.57%, the Zarigan deposit between 0.5 and 1.2% and the Lak-e-Siah deposit varies between 0.45 and 1.36%. Concentrations of ∑REE within the apatite crystals present within the IOA ores in the Esphordi, Lak-e-Siah and Homeijan deposits have ranges between 1.9-2.54%, 1.9-2.16% and of 2.55%, respectively. These elements are mainly concentrated in apatite crystals, but other minerals such as monazite, xenotime, bastnasite, urtite, alanite, thorite, parisite-synchysite and britholite have been recognized as hosts of REEs, as small inclusions within the apatite crystals, and in subsequent carbonate, hematite-carbonate and quartz veins and veinlets. Given the extent of this block and the presence of several IOA deposits within this block, and also the high grades of REEs within these deposits, one can reasonably state that it is obvious that there are significant resources of REEs in this part of Iran.

Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

“…Various studies of IOA deposits have proposed different petrogenetic models including magmatic (e.g., [58,66]), magmatic-hydrothermal [67], hydrothermal (-metasomatic) (e.g., [68][69][70]), and sedimentary exhalative (e.g., [71,72]). For the Bafq district, some researchers have referred to a magmatic model [17,28,73,74], whereas Torab and Lehmann (2007) [35], Jami (2005) [21], and Daliran (2010) [19] considered high-T hydrothermal fluids as being responsible for generation of some Bafq IOA deposits. Taghipour et al (2013) [75] argued that mixing of magmatic and non-magmatic fluids caused iron oxide mineralization and hydrothermal alteration in the Choghart deposit.…”

Mineralogy of various types of Th-U-REE mineralisation in the iron oxide – apatite deposits of the Bafq district, Central Iran

“…The economically most important iron oxide-apatite deposits of this district include Choghart, Se-Chahun, Chahgaz, Chadormalu and others. The Bafq district contains reserves of over 2 billion tonnes of iron ore within 38 major iron oxide-apatite anomalies over an area of 7500 km 2 (Mokhtari 2015). The hydrothermal magnetite-apatite mineralisation, which is commonly formed as a result of the multistage interaction of hydrothermal-magmatic processes within the Early Cambrian volcano-sedimentary sequence, occurs mostly as massive orebodies and metasomatic replacements with locally elevated rare-earth element (REE) contents and peripheral Th/U-REE mineralisation (Daliran 2002).…”