THE INFRARED SPECTROSCOPIC FEATURES OF CHROMITE IN THE MENGYIN DIAMOND DEPOSIT IN SHANDONG PROVINCE: Significance in ore prospecting

Chromite is one of the key indicators for ore potentiality of kimberlite type diamond deposits. With systematical collection of infrared spectra of the chromites from kimberlite pipes in the Mengyin diamond orefield in Shandong Province, the infrared spectroscopic features of the chromites in barren, poor, medium-ore-bearing and rich ores are respectively analyzed, to find out their relation to the ore potentiality of the kimberlite. The statistic results show that, from barren, poor, medium-ore-bearing to rich ores, the average ratios of absorbance of A-peak and high-frequency peak of the infrared spectra are 0.71, 0.73, 0.83-0.93 and 1.09, respectively, with a significant indication.