RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 8, ES3002, doi:10.2205/2006ES000196, 2006

Figure 25. Mineralogical prediction map of the Rai-Iz Massif (prepared
based on the results of 1 : 50,000-scale mineralogical mapping
[Makeyev and Bryanchaninova, 1999]).
(a) Map showing the composition of accessory Cr-spinel from the
Rai-Iz Massif. Colors correspond to variations in the composition of
accessory Cr-spinel in the ultrabasite rocks (IR spectroscopic
data, isopleth map of the
n1, cm-1, parameter): 1 -
> 644;
2 - 644-638; 3 - 638-631; 4 - 631-624; 5 - 624-605; 6 -
< 605.
The variations in the
n1 parameter roughly correspond to the compositional
variations from (1) picotite to (2, 3) aluminochromite, (4) chromite,
(5) ferrichromite and chrome-magnetite, and (6) magnetite.
(b) Map showing the Fe# of the rock-forming olivine from the Rai-Iz
Massif. Colors correspond to variations in the index of
refraction ng of olivine: 1 -
< 1.682; 2 - 1.682-1.684; 3 - 1.684-1.686;
4 - 1.686-1.688; 5 - 1.688-1.690; 6 - 1.690-1.692; 7 - 1.692-1.694;
8 - 1.694-1.697; 9 -
> 1.697. The variations in
the ng
parameter roughly correspond to variations in the olivine
composition from 2% to 14% of the fayalite end member.
(c) Technological map of the quality of Cr ores at the Rai-Iz
Massif. 1 - Mineral deposits; 2 - occurrences of ore mineralization;
3 - occasional grains of Cr ore minerals. Quality of Cr ores:
4 - high-grade metallurgical chromite ores; 5 - low-Cr metallurgical
Cr ores (aluminochromite and subferialuminochromite); 6 - low-Cr
Cr ores for chemical industry (low-Cr aluminochromite and
subferrialuminochromite); 7 - low-Cr Cr ores (Cr-picotite and
subferrichromepicotite); 8 - lean disseminated metamorphosed
refractory Cr ores (ferroferrichrome-spinel).
(d) Prediction map of the Cr ore potential of the Rai-Iz Massif.
Areas delineated as promising for exploration: 1 - for large
deposits of high-grade metallurgical chromite ores; 2 - for
middle-sized deposits; 3 - for small deposits; 4 - for small
deposits of high-Al Cr ores for chemical
industry.

Citation: Makeyev, A. B. (2006), Typomorphic features of Cr-spinel and mineralogical prospecting guides for Cr ore mineralization, Russ. J. Earth Sci., 8, ES3002, doi:10.2205/2006ES000196.
Copyright 2006 by the Russian Journal of Earth Sciences
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