<P> The achean basement served as a rigid indentor which controlled the overall wedge shaped geometry of the orogen . Lithology of area shows that the base rocks of Aravalli are of Mewar Gneiss formed by high - grade regional metamorphic processes from preexisting formations that were originally sedimentary rock with earliest life form that were formed during the archean eon, these contain fossils of unicellular organism such as green algae and cyanobacteria in stromatolitic carbonate ocean reefs formed during the paleoproterozoic era . Sedimentary exhalative deposits of base metal sulfide ores formed extensively along several, long, linear zones in the Bhilwara aulacogen or produced local concentration in the rifted Aravalli continental margin, where rich stromatolitic phosphorites also formed . Tectonic evolution of the Aravalli Mountains shows Mewar Geniss rocks are overlain by Delhi Supergroup type of rocks that also have post-Aravalli intrusions . Metal sulfide ores were formed in two different epocs, lead and zinc sulfide ores were formed in the sedimentary rocks around 1.8 Ga years ago during Paleoproterozoic phase . The tectonic setting of Zinc - lead - copper sulfides mineralization in Delhi supergroup rocks in Haryana - Delhi were formed in mantle plume volcanic action around 1 Ga years ago covering Haryana and Rajasthan during mesoproterozoic . In the southern part of Aravalli supergroup arc base metal sulfides were generated near the subduction zone on the western fringe and in zones of back - arc extension to the south - east . Continued subduction produced W - Sn (Tungsten - Tin) mineralisation in S - type (sedimentary unmetamorphosed rock) felsic (volcanic rock) plutons (underground crystallised solidified magma). This includes commercially viable quantities of minerals, such as rock phosphate, lead - zinc - silver mineral deposits at Zawar, Rikahbdev serpentinite, talc and pyrophyllite) and asbestos, apatite, kyanite and beryl . </P> <P> Mining of copper and other metals in the Aravalli range dates back to at least 5th century BC, based on carbon dating . Recent research indicates that copper was already mined here during Sothi - Siswal period going back to c. 4000 BCE . Ancient Kalibangan and Kunal, Haryana settlements obtained copper here . </P> <P> The Aravalli Range can be divided into the following parts (north to south direction): </P> <Ul> <Li> Archean basement, is a Banded Gneissic Complex (BGC) with schists (medium grade metamorphic rock), gneisses (high grade regional metamorphic rock), composite gneiss and quartzites . It forms the basement rock for both Delhi Supergroup and Aravalli Supergroup . </Li> <Li> Delhi Supergroup <Ul> <Li> Alwar Group, with arenaceous and mafic volcanic rocks <Ul> <Li> Delhi Ridge, in north </Li> <Li> Haryana Aravalli ranges, in the west <Ul> <Li> Tosham Hill range, basement rocks are quartzite with chiastolite, the upper layers of quartz porphyry ring dyke, felsite, welded tuff and muscovite biotite granite rocks have commercially nonviable tin, tungsten and copper . </Li> </Ul> </Li> <Li> Rajasthan Alwar range, in the east </Li> </Ul> </Li> <Li> Ajabgarh Group - Kumbhalgarh Group, with Carbonate, mafic volcanic and argillaceous rocks </Li> <Li> Raialo Group, with Mafic volcanic and calcareous rocks </Li> </Ul> </Li> <Li> Aravalli Supergroup <Ul> <Li> Debari Group, with Carbonates, quartzite, and pelitic rocks </Li> <Li> Jharol Group, with Turbidite facies and argillaceous rocks </Li> </Ul> </Li> </Ul>

North aravali region of rajasthan include which district