A VMS LIKE COPPER-GOLD MINERALIZATION IN THE ALWAR BASIN OF NORTH DELHI FOLD BELT, WESTERN INDIA: EVIDENCES FROM GEOLOGICAL ASPECTS

The Paleoproterozoic meta-sedimentary belts of Rajasthan, western India are known for basemetal mineralization which hosts some classic Pb, Zn and copper deposits. Apart from the well established Khetri copper deposit, smaller occurrences and discoveries of copper mineralization have been reported from western India. The recent discovery of Mundiyawas-Khera copper deposit by Geological Survey of India within the Paleoproterozoic Delhi Supergroup of rocks in Rajasthan, which reports 26.30 million tons of Cu ore with 0.34% cut off, has a special stature as compared to the Khetri copper belt. Unlike the Khetri copper deposit, which is being suspected as an IOCG type mineralization by some researchers, Mundiyawas-Khera copper deposit has a different status and has much similarity with a VMS type depositional environment. The lithosequence exposed in the area belong to the Proterozoic Delhi Supergroup and consists of a thick pile of meta volcano-sedimentary rocks. Besides copper in the form of chalcopyrite ore, associated precious metals like Au and Ag mineralization are observed in native state as well as in alloy form from the Mundiyawas-Khera area. The ore mineralization is primarily hosted by a thick pile of volcano-sedimentary sequence comprising of felsic volcanic rocks of rhyo-dacitic nature, dolomitic marble and tuffaceous material. Sulfur isotopic composition of the ore minerals indicate δ³⁴SVCDT (‰) values between 0 ‰ and 3.79 ‰. The range of sulfur isotopic values in Mundiyawas Khera from -4.35‰ to + 3.79‰ typically correspond to a magmatic source. Mode of occurrence, host rock association, hydrothermal alteration patterns, style of mineralization augmented with micro-textural studies predicts the mineralization to be VMS like mineralization in the Mundiyawas-Khera area.