Regional assessment of Marble and calc-silicate
rocks of Rajasthan.
This strong calc-silicate
alteration, that includes garnet, has proven to be a good indicator of base metal mineralisation at Jervois, suggesting close proximity to mineralisation.
According to the company, although graphite has been identified locally in marbles, graphite is also hosted here in quartz, biotite/mica gneisses and in calc-silicate
The ADD is a 100-300 m-thick mylonite zone of interlayered quartzite, marble, calc-silicate
If the protolith is siliceous carbonate, then calc-silicate
minerals will be part of the mineral paragenesis.
However, we have also found zeolites in various granitic pegmatites, nepheline syenitic pegmatites, fractured diabase dikes, calc-silicate
gneisses and fenites in the same area, and in agpaitic rocks and calc-silicate
skarns in the CMBBZ.
But impure marbles (containing silicate and calc-silicate
minerals) can be challenging to slab and polish, especially if the impurities occur as patches rather than being finely disseminated.
The gold is localized in calc-silicate
altered serpentinite and in sheared metabasalt near a fault contact between these rock types.
The HHC forms the hanging wall of the Main Central Thrust (MCT) and incorporates pelitic, psammitic and quartzite sequences together with thin amphibolite and calc-silicate
bands along with granitoids of various ages.
1962) state that apophyllite can occur in fissures in metamorphic rocks bordering granite, and in limestone or calc-silicate
rock associated with calcite, sometimes as an alteration product of wollastonite.
Gold anomalies up to 1,400 ppb are also found in scheelite-bearing calc-silicate
zones which can be followed intermittently for 3.