RELATION OF PIPILIA DYKE SWARMS WITH 1800–1700 MA LARGE IGNEOUS PROVINCE (LIP): APPROACH TO COLUMBIA/NUNA SUPERCONTINENT ASSEMBLAGE FROM DOLERITE DYKES IN SINGHBHUM CRATON, INDIA

Periodical assembly and breakup of a majority, or all, of Earth's crustal blocks have occurred several times in Earth’s history. Large Igneous Provinces (LIPs) is a fabulous new method to get a sense of robust Precambrian continental reconstruction. Comparison of the LIP barcode record between crustal blocks allows identification of nearest neighbor blocks in past supercontinents. In this case, dyke swarms are considered as the erosional remnants of LIPs and provide an insight into supercontinent assemblage and break up processes.

The NW-SE trending Pipilia dyke swarm from Singhbhum Craton is very similar in age to the dykes in North China Craton, Rio de Plata Craton, Sarmatia (Baltica), Northern Australia, Siberia, Congo-Sao Francisco and Amazonia, as shown by previous workers. In addition, dyke swarms from these cratons having ages in the range of 1790–1750 Ma are showing characters of subduction related metasomatized mantle source. Age similarity of dyke swarms from these crustal blocks suggests that they were together in former Columbia Supercontinent assemblage. The precise Pb–Pb Baddeleyite age of dykes from Pipilia dyke swarm of Singhbhum Craton are recently found to be 1766.2±1.1 Ma and 1764.5±0.9 Ma, which is well within the time range mentioned above and showing enriched LILE and LFSE and depleted HFSE(Nb) patterns, concluding subduction related metasomatized mantle source. The constructed barcode diagram shows the matching of dyke swarms of similar age from all the aforementioned shield areas, newly including Singhbhum Craton. Similarity in ages and geochemistry of dykes suggest that Singhbhum Craton was adjacent to and grouped with these crustal blocks at the time of Columbia (Nuna) assembly.