Dear Mr. Muhammad,
Molybdenite mineral is characterized by high significant concentrations of rhenium which incorporate into its structure at concentrations ranging from some ppb to a few thousand ppm.
The major controlling factors of the Re distribution in molybdenite from porphyry Cu-Mo deposits may be the composition of parent magma, the concentration of Re in ore-forming fluid and variations of physical and chemical conditions of crystallization.
Molybdenite can be dated by Re-Os dating method where rhenium is a chalcophilic element decays to osmium by releasing beta particles (Negatron decay) and that make it useful tool to date the formation of sulfide minerals.
For more information about Re-Os dating method, you can read the following papers.
Best regards.
hii Mr. Muhammad,
Some recent published paper on Molybdenite by Re-Os method:
http://www.sciencedirect.com/science/article/pii/0016703796001640
http://www.sciencedirect.com/science/article/pii/S0169136815303000
http://onlinelibrary.wiley.com/doi/10.1111/rge.12091/pdf
The Re–Os (rhenium–osmium) chronometer applied to date molybdenite (MoS2).
Success of dating of molybdenite depends on proper preparation of the mineral separate and analysis of a critical quantity of molybdenite, unique to each sample, where spatial decoupling of 187Re parent and 187Os daughter within individual molybdenite crystals has to be taken care.
Highly precise age results are obtained by isotope dilution and negative thermal ion mass spectrometry (ID-NTIMS).
Use of a reference or control sample is necessary to establish laboratory credibility and for comparisons.
Do not attempt to make your own molybdenite concentrate for Re-Os dating; Best is to send the crystals in their natural matrix and the specialized lab will do the separates avoiding contamination.
Dear Muhammad: molibdenyte is a source of renium, a scarce metal. The 187Re isotope decays through beta particle emission to 187Os, in an isobaric decay scheme, with a long half-life of 45.6 +- 1.1 Ga and a decay constant of 1.52 +- 0.04 x 10-11/y, providing an excelent geochronometer for MoS2 and other Mo-containing ores, such as Cu-porphyries. This long half-life allows to treat the decay as a straight isochrone, like in the Rb-Sr method. A good description of the Re-Os method of dating can be found in the thet by Gunter Faure (1986) "Principles of Isotopic Geology", John Wiley and Sons, 2nd Ed., New York: 589 pp. Chapter 16 of this text, from pages 264-271, is dedicated to this method. Interesting to read is the dating of the famous "iridum" anomaly in the K-T boundary, corresponding to the impact of the asteroid that formed the Chicxulub Crater, in northern Yucatan Peninsula, Mexico. However, as M. Zentilli warns, the concentrations of both isotopes are in the low ppm range, therefore no handling of the samples can be made except in very specialised laboratories. Mexico. Regards. Sebastian.
