Geochemistry, mineralogy and economic potential of titano-hematite rock of the samchampi carbonatite- alkaline rock complex, Karbi-Anglong district, Assam, India

摘要: Two, large stock-like bodies of titano-hematite rock (THR) occur prominently (c.2.5 sq.km. in outcrop area) the dominantly soil covered carbonatite-alkaline ring complex Samchampi that was emplaced close proximity to Kalyani lineament during Upper Cretaceous (c. 109 Ma ago) Mikir Hills massif Assam. Petrographic studies indicate hematite is predominant ore mineral with minor amounts ilmenite and accessory phases perovskite, pyrochlore crandallite. Ore textures exhibit well developed exsolution lamellae along octahedral cleavages original magnetite has been completely martitised. The average major oxides (in wt.%) trace elements ppm) composition THR (14 samples) are as follows: SiO2 1,10, TiO2 3.44, Al2O3 3.91, Fe2O3 81.27, Feo 0.58, MnO 0.25, MgO 0.39, CaO 0.49, Na2O O.04, K2O 0.01, LOI 6.23, V 1787, Sr 2002, Ba 263, Zr 794, Nb 2201, Y 142 total REE 3672 (12 samples). EPMA have revealed distinct presence such pyrochlore, crandallite, perovskite account for chemical constituents other than ore. Based on geological geophysical (ground magnetic) studies, a reserve 75 million tons inferred up depth 30 m Ganjang (I&II) Thulbhung blocks. Thus could become potential source iron Ti, co-products region besides phosphatic rocks 15 10 grade 35% P2O5) curvilinear fault zones complex.