Document Type : Original Research Paper
Authors
1 Ph. D., Department of Geology, Faculty of Earth Science, Shahid Beheshti University; Geological Survey of Iran, Tehran, Iran
2 Professor, Department of Mining, Metallurgy and Petroleum Engineering, Amirkabir University, Tehran, Iran
3 Assistant Professor, Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran
4 Associate Professor, Faculty of Geology, College of Science, University of Tehran, Tehran, Iran
5 M.Sc., Exploration Management, National Iranian Copper Industries Co, Sarcheshmeh, Iran
Abstract
Bondar Hanza porphyry copper deposit occurs 150 km southeast of Kerman, in southern part of the Urmia-Dokhtar zone and in Dehaj-Sardoiyeh zone. This ore deposit has formed in diorite to granodiorite rocks. The present paper deals with the study of fluid inclusion on quartz and hornblende samples as well as the measurement of isotopic ratio of oxygen and hydrogen with the aim to recognize characterization of hydrothermal fluids effective in mineralization. The studied veinlets are divided into five groups. Veinlet I: fluid of high pressure (>300 MPa) and medium to high temperature (250°C-300°C) with salinity of 38-45 Wt%NaCl that includes molybdenum mineralization. This veinlet contains halite and anhydrite and has resulted in potassic and sodic-calcic mineralization in deeper parts of the ore deposit. Veinlet II: high pressure (>300 MPa), high salinity (33-47 Wt%NaCl) and high temperature (250°C-420°C), containing copper and molybdenum mineralization as well as potassic alteration. Veinlet III: high salinity (40-56 Wt%NaCl), high pressure (>300 MPa) and high temperature (200°C-500°C), containing copper mineralization. Veinlet IV: medium to low salinity (6-7 Wt%NaCl), medium temperature (approximately 170°C), low pressure (0/7-0/8 MPa), containing no mineralization. The study performed indicate that the boiling occurred in the initial magma, as a result of pressure and temperature changes and mixing with meteoric waters, caused copper and molybdenum mineralization. Results obtained from oxygen and hydrogen isotopic analysis in quartz show δ18O to vary from 3.9 to 6.3 per mil. Considering its formation temperature and based on thermometric study (130-400°C), the amount of δ18o in mineralizing fluid is from 5.26 to 6.19 per mil, being indicative of magmatic origin of mineralization fluids like the other porphyry copper deposits of Iran and the world. While results of hydrogen analysis existed in fluid inclusions of quartz mineral illustrate a range between -88 to -90 per mil, being indicative of a decrease in the amount of mineralizing fluid deuterium. These values are traceable to the effect of meteoric waters, given the propylithic and sodic alterations accompanied with potassic alteration in mentioned veinlet.
Keywords
)