EPMA monazite geochronology of the granulites from Daltonganj, eastern India and its correlation with the Rodinia supercontinent

We report the monazite dates of the granulites from Daltonganj (Palamau), Chhotanagpur granite-gneiss complex (CGGC) which covers the significant part of the granulite blocks in central India by using an electron micro probe analyser dating. The monazite grain varies between 70 and 80 mu m and shows the distribution of U, Th and Pb in all monazite grains of both samples. Two different dates were obtained from different monazite grains; the first age suggests that the granulite from CGGC preserves the first remnant of the protolith of the Mesoproterozoic era at similar to 1424 Ma and second one at similar to 972 Ma which provides evidence of metamorphism of the protolith. The CGGC rocks preserve four regional metamorphic events, namely M-1, M-2, M-3 and M-4. But in this work, two different ages from the Daltonganj granulites were obtained which are similar to the M-2 (<1500 Ma, i.e., the age of protolith of the granulitic gneiss) and M-3 (1200-930 Ma) metamorphic events as reported in the CGGC. The M-3 metamorphism attained its average P-T condition at similar to 7.35 kbar/792 degrees C, and it represents the prograde metamorphic event. The M-3 metamorphic event supported the Grenville-orogeny, and it was responsible for the metamorphism of the magmatic protolith of granulitic gneiss from the CGGC at the time of amalgamation of the Rodinia supercontinent. The Rodinia assembly had occurred through the global Grenville-orogenic events between 1100 and 900 Ma, with continental blocks which exist at that time.