Give economic importance of Aravalli craton.
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Natural History
Geology
Main article: Tectonic evolution of the Aravalli Mountains
See also: Geology of India
minerals
The archean basement had 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.[11][12]
Mining
Mining of copper and other metals in the Aravalli range dates back to at least the 5th century BCE, based on carbon dating.[13][14] Recent research indicates that copper was already mined here during the Sothi-Siswal period going back to c. 4000 BCE. Ancient Kalibangan and Kunal, Haryana settlements obtained copper here.[15]
Geographical features
See also: Tectonic evolution of the Aravalli Mountains § General formation
The Aravalli Range, seen from the range's highest point at Guru Shikhar, in Rajasthan.
The Indian Craton comprises the five major cratons. Cratons are part of continental crust made up of upper layer called platforms and older bottom layer called basement rocks. sheilds sheilds is part of craton where basement rock crops out of the ground and it is relatively oldest and most stable part that are unaffacted by the plate tectonics. Aravalli Craton (Marwar-Mewar Craton or Western Indian Craton): Covers Rajasthan as well as western and southern Haryana. It comprises Mewar Craton in the east and Marwar Craton in thw west. It is limited by the Great Boundary Fault in the east, sandy Thar Desert in the Thar desert in the west, Indo-ganetic alluvium in the north, Son-Narmada-Tapti in the south. It mainly has quartzite, marble, pelite, Greywacke and extinct volcanos exposed in Aravalli-Delhi Orogen. Malani Igneous Suite is the largest in India and third largest igneous suit in the world.[16][17] The uniqueness of the geological feature of Malani Igneous Suite at Jodhpur prompted the Geological Survey of India (GSI) to declare the site as a National Geological Monument.[18]