Abstract
Manganese silicate rocks interbedded with manganese oxide ores occur enclosed in phyllites of the Precambrian Aravalli Group in and around Kajlidongri, Jhabua District, Madhya Pradesh. The phyllites are metamorphosed up to the biotite zone of regional metamorphism. The manganese oxide minerals in the bedded ore deposits are braunite and hematite of two generations, bixbyite and jacobsite associated with spessartite and alurgite. A granite body and a few small calcareous bodies present in the area are younger than the phyllites and the enclosed manganese deposits. Epigenetic veins cutting across all the formations are important in this area. Though the mineral composition of the veins are in general simple, being constituted by quartz and calcite, a number of minerals are present in them and the surrounding wall rocks where they intersect bedded manganese deposits. Their unusual mineral composition containing aegirine-augite, micaceous hematite, richterite, zoisite, cummingtonite, scapolite, barite, fluorite, hollandite, blanfordite, brown manganese pyroxene, winchite, tirodite, alurgite, piedmontite, manganophyllite, tilasite, pyrolusite and cryptomelane is explained from field and textural evidences as due to reconstitution of the sedimentary manganese by the effect of the epithermal veins.
An interesting feature of the phyllites is the presence of fluid inclusions in quartz which have a definite pattern of abundance in relation to the granite and the carbonate bodies. The petrographic characters of the carbonate bodies indicate their replacement origin apparently due to the activity of fluids derived from granite.
