SHRIMP geochronology for the 1450Ma Lakhna dyke swarm: Its implication for the presence of Eoarchaean crust in the Bastar Craton and 1450–517Ma depositional age for Purana basin (Khariar), Eastern Indian Peninsula

Geodynamic Significance of the Updated Statherian-Calymmian (at C. 1.65 and 1.46 Ga) Palaeomagnetic Results from Mafic Dykes of the Indian Shield

“…A few dykes with moderately steep directions spatially closer to steep 3 or steep 4 directions but statistically different from these groups have remained ambiguous. We find that the moderately steep magnetization is statistically in remarkable agreement with the results reported for the 1466.4  2.6 Ma dykes 20 , while magnetization of the four dykes reported by Pisarevsky et al 12 overlaps steep 1, steep 2 or steep 4 directions. Here we update the palaeomagnetic record of this early Mesoproterozoic period based on the analysis of combined data.…”

“…Radhakrishna et al 17 have reported another event of distinct dyke emplacement based on palaeomagnetic results in the Bundelkhand craton for which an age could not be assigned. In addition, a few dykes in the Lakhna area of the eastern Bastar craton (Figure 1) represent an entirely different magnetization dated at 1466.4  2.6 Ma by U-Pb baddeleyite geochronology 12,20 . All the dated dykes are near N-S trending and include three rhyolites and one coarse gabbro.…”

Petrology of Lamproites from the Nuapada Lamproite Field, Bastar Craton, India

“…Therefore, it is important to understand the temporal and tectonic evolution of these basins as well as of pertinent igneous activities in the region. The Khariar basin started opening at 1455 ± 47 Ma (Das et al 2009), which is broadly synchronous with the intrusion of the 1450-1465 Ma Lakhna dykes to the east of the basin (Ratre et al 2010;Pisarevsky et al 2012). Age constraint on the upper limit of sedimentation comes from the Chhattisgarh basin, where felsic volcanism is recorded at *1000 Ma in the form of rhyolitic tuffs in the upper part of the sedimentary succession Bickford et al 2011).…”

“…Two N-S-trending granophyre dykes occur in the eastern part of the study area. One of these dykes, which is located west of Saipala, is *8 km long and has yielded a U-Pb zircon age of 1,450 ± 22 My (Ratre et al 2010). The dyke contains a zircon xenocryst, which has yielded a Pb-Pb zircon age of 2,563 ± 22 My that could represent the intrusive age of the grey granitoid host.…”

“…Most of the Lakhna dykes are oriented N-S, while a few trend E-W to NW-SE. The dykes have yielded ages in the range of 1450-1465 My (Ratre et al 2010;Pisarevsky et al 2012). French et al (2008) dated a mafic sill in the Cuddapah basin of the Dharwar Craton as *1.9 Gy old and proposed that the Bastar-Cuddapah mafic igneous activity represented a large igneous province emplaced in the Dharwar and Bastar cratons at *1.9 Ga. Palaeomagnetic results from mafic dykes lend credence to the notion of temporal and spatial link between the Dharwar and Bastar cratons by *1.9 Ga (Meert et al 2011) and between the Bastar and Bundelkhand cratons by *2.0 Ga (Pradhan et al 2012).…”