Multiphase magma intrusion, ore-enhancement and hydrothermal carbonatisation in the Siah-Kamar porphyry Mo deposit, Urumieh-Dokhtar magmatic zone, NW Iran

Abstract

The Siah-Kamar Mo deposit (SKMD) is located at the northwestern termination of the Urumieh-Dokhtar magmatic zone and it is the only porphyry Mo ore reserve in Iran. The exploration program documented 39.2 Mt proved reserves @ 539 ppm Mo and 66.4 Mt probable reserves @ 266 ppm Mo. In this study, field and petrographic investigations, integrated with geochemical (fluid inclusion and quartz chemistry) and geochronological (U-Pb zircon, Re-Os molybdenite, and Rb-Sr multimineral isochron) studies are used to propose a metallogenic model for the Mo mineralisation in the SKMD. The geology of the SKMD is characterized by the emplacement of a multiphase Oligocene basic/intermediate (at ca. 33-30 Ma) to acidic (29-28 Ma) magmatic suite, which intruded the Eocene volcanic country rocks. presence of a possible pre-enriched crustal material should be considered responsible for the Mo endowment in the UDMZ.

Hydrothermal genesis and growth of the banded agates from the Allumiere-Tolfa volcanic district (Latium, Italy)

“…The fluid-driven hydrothermal genetic environment for the studied sample is also well highlighted by the LA-ICP-MS trace element chemistry (Fig. 11; see also Rabiee et al 2019). It is worth noting that the positive correlation between Al and Li in the hyaline quartz (and chalcedony) from the investigated sample.…”

“…11a) shows positive correlations for all layers. Noteworthily, the data points for quartz (Al/Li 2.3 mean value) falls near the 1:1 Al/Li ratio trend typical of hydrothermal and magmatic quartz (e.g., Dennen 1966;Müller et al 2018;Rabiee et al 2019) whereas those for cristobalite (Al/Li 83.9 mean value) and chalcedony-moganite layers (Al/Li 58.7 mean value, with chalcedony and moganite having Al/Li 43.4 and 82.5 mean values, respectively) are well discriminated by Al/Li ratios higher than the 15:1 trendline. The hydrothermal genetic environment is highlighted also by the Al vs. Ge diagram (Fig.…”

“…11c); moreover, the logarithmic Ti vs. Al diagram (Fig. 11d; after Rusk 2012; Müller et al 2018;Rabiee et al 2019) suggests a possible affinity with the conditions of orogenic Au-bearing quartz deposits typically constituted by chalcedony and cryptocrystalline quartz mineralization (e.g., Kogen and Timachev 1969;Klein and Fuzikawa 2010).…”

“…Trace element distribution may be useful in identifying the genetic environment of the studied agate sample (e.g., Müller et al 2018;Rabiee et al 2019). We thus collected LA-ICP-MS (laser ablation induced coupled plasma mass spectrometry) data (i) on cristobalite outer rims (#4 spots), (ii) on the main chalcedony-moganite bands (#62 spots corresponding to #10 spots on moganite-poor layers, #9 spots on moganite-rich layers and #43 spots intermediate moganite content bands) and (iii) on the inner portion consisting of hyaline euhedral quartz crystal (#37 spots).…”

The Van Microplate: A New Microcontinent at the Junction of Iran, Turkey, and Armenia

“…These volcanic and plutonic rocks are widely distributed, and they cut the Eocene volcanic rocks. Mainly Cu-Mo-Au deposits and Fe mineralization Siani et al, 2015;Mehrabi et al, 2016;Rabiee et al, 2019) occurred during magmatic activity in the western and southern areas of the Caspian Sea.…”