Origin and Evolution of Ore-Forming Fluids in the Magnetite±Apatite Lake Siah Deposit (Bafq): Evidence of Fluid Inclusions and Oxygen Stable Isotope

Tale Fazel, Ebrahim; Rostami, Mahin

doi:10.29252/gnf.5.2.217

Volume 5, Issue 2 (Autumn&Winter 2020) KJES 2020, 5(2): 217-234 | Back to browse issues page

‎ 10.29252/gnf.5.2.217

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Tale Fazel E, Rostami M. Origin and Evolution of Ore-Forming Fluids in the Magnetite±Apatite Lake Siah Deposit (Bafq): Evidence of Fluid Inclusions and Oxygen Stable Isotope. KJES 2020; 5 (2) :217-234
URL: http://gnf.khu.ac.ir/article-1-2694-en.html

Origin and Evolution of Ore-Forming Fluids in the Magnetite±Apatite Lake Siah Deposit (Bafq): Evidence of Fluid Inclusions and Oxygen Stable Isotope

Ebrahim Tale Fazel ^*

¹, Mahin Rostami²

1- Bu-Ali Sina university , tale.fazel@gmail.com
2- Bu-Ali Sina university

Abstract: (1720 Views)

The Lake Siah magnetite ± apatite deposit is situated in the northeastern of Bafq and Central Iran tectonic zone. The host rock of deposit is composed of lower Cambrian volcano-sedimentary sequence that has exposed as caldera complex. The iron mineralization includes magnetite and hematite with apatite, quartz and calcite as gangue minerals. Based on fluid inclusion petrography in quartz and apatite, at least five types of fluid inclusions are recognized including multi-phase solid bearing (L+V+S₁+S₂), three phase solid bearing (L+V+S), liquid-rich two phase (L+V), vapor-rich two phase (V+L) and monophase vapor (V(. The three phase fluid inclusions are the most abundant of fluid inclusions type and indicate homogenization temperature between 123 to 530°C (avg. 344°C) and salinity content of 30 to 58 wt% NaCl equiv. (avg. 40.60 wt% NaCl equiv.). Three phase fluid inclusions in the apatite are characterized by homogenization temperature of 175 to 420°C (avg. 385°C) and salinity of 34 to 53 wt% NaCl equiv. (avg. 41.58 wt% NaCl equiv.). Estimated pressure on the basis of microthermometric measurements on fluid inclusions in the H₂O-NaCl system is between 10 to 500 bar which is corresponding to depth of 0.5 to 1.5 km. The values of δ¹⁸O of fluid in equilibrium with quartz are 7.5 to 11 ‰ which indicate magmatic fluid origin. According to wide range of fluid inclusion homogenization temperature and salinity accompanied with positive correlation between salinity and homogenization temperature of fluid inclusions, mixing of hot and high salinity fluid with cold and low salinity water (similar to meteoric waters) is the main factor for occurrence of the Lake Siah deposit.

Keywords: Magnetite±apatite, Lower Cambrian volcano-sedimentary, Caldera complex, Lake Siah, Bafq.

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Type of Study: Original Research | Subject: Economic Geology
Received: 2019/02/15 | Accepted: 2019/07/14 | Published: 2020/02/10