Parampreet Kaur

A number of gra nitoid plutons were emplaced in the northernmost entity of the Aravalli craton, the Khetri Copper Belt (KCB). We report here Th-U-Pb ele ctron probe micro analyser chemical ages for zircon and monazite from two granitoid plutons of the north KCB, the Biharipur and Dabla. Zircons occurring in the granitoids depict well-developed magmatic zoning and are chronologically unzoned. Both the plutons and their diverse granitoid facies are coeva l and provide ages around 1765-1710 Ma. Geochemical attributes of the studied plutons are typical of A -type within-plate granites and consistent with an exte nsional tectonic environment. Our new age data are comparable to the petrologically similar A-type granitoids of the Alwar re- gion, which have provided zircon chemical ages around 1780-1710 Ma. These analogous ages imply a widespread late palaeoproterozoic extension-related plu- tonism in the northern part of the Aravalli craton. The monazites, which were recovered only from th...

ABSTRACT This work presents a synthesis of major metallic deposits formed during Columbia supercontinent cycle. Main deposits, such as orogenic Au, volcanogenic massive sulphides (VMS), Mississippi Valley-type (MVT) Pb-Zn, unconformity-associated uranium, Mo-Cu-Ag deposits, and perhaps clastic-dominated (CD) Pb-Zn deposits (Rajasthan, India) were formed during the assembly of Columbia. The similar to 1.9 Ga global-scale mafic-ultramafic event, aided by large-scale mantle upwelling, played a significant role in the formation of granular iron formations, VMS, and magmatic Ni-Cu sulphides. The enveloping cratonic blocks of the supercontinent seem to have exerted a significant control in the selective preservation of the rock record, and thus there was a greater preservation potential of mineral deposits during the assembly of Columbia. Very few deposits were recorded in the Earth history during the assumed dispersal of Columbia at around 1.3-1.2 Ga because of poor preservation potential or destruction of rock record during the breakup phase of a supercontinent cycle. The intervening time period between assembly and breakup of Columbia, which was marked by many attempted breakup phases, formed some major deposits, such as iron oxide-copper-gold (IOCG) and U (e.g. Olympic Dam), CD Pb-Zn (e.g. Broken Hill), CD Pb-Cu, sedimentary-rock hosted stratiform copper, Fe-Ti-V deposits, and perhaps Sn deposits of the Amazonian craton.