Palaeomagnetic, geochronological and geochemical study of Mesoproterozoic Lakhna Dykes in the Bastar Craton, India: Implications for the Mesoproterozoic supercontinent

Abstract

18 Palaeomagnetic analysis of the Lakhna Dykes (Bastar Craton, India) yields a palaeopole at 36.6°N, 19 132.8°E, dp=12.4°, dm=15.9°, and the U-Pb zircon age obtained from one of the rhyolitic dykes is 20 1466.4 ± 2.6 Ma (MSWD=0.21, concordia age based on two analyses with identical Pb/U ages), 21 similar to previously published U-Pb ages. Major and trace element analyses of the Lakhna Dykes 22 30 2 model. Our preferred reconstruction implies a long Palaeo-to Mesoproterozoic accretionary orogen 31 stretching from south-eastern Laurentia through south-western Baltica to south-eastern India. Breakup 32 of India and Baltica probably occurred in the Late Mesoproterozoic, but additional constraints are 33 needed. 34

Reconstructing South China in Phanerozoic and Precambrian supercontinents

“…India suggest it was tied to Baltica within the Nuna supercontinent (Pisarevsky et al, 2013;Pisarevsky et al, 2014). In this paleomagnetically constrained reconstruction, the Dharwar Baltica separated between 1120-1080 Ma (Pisarevsky et al, 2013).…”

“…In this paleomagnetically constrained reconstruction, the Dharwar Baltica separated between 1120-1080 Ma (Pisarevsky et al, 2013). Geological evidence for this breakup event is limited due to subsequent overprinting events but data from southern…”

Kimberlites, Lamproites, Lamprophyres, Carbonatites, other Alkaline Rocks, and Mafic Dykes from the Indian Shield: Glimpses of Research (2012-2016)

“…Although, early Precambrian mafic dykes are well exposed in the southern parts of the Bastar craton (Srivastava et al, 2016), they have also been encountered in the middle (Srivastava and Gautam, 2012) and the northern (Pisarevsky et al, 2013;Srivastava and Gautam, 2015) parts of the Bastar craton. Pisarevsky et al (2013) have presented paleomagnetic, geochronological and geochemical data on the ~N-S trending Mesoproterozoic Lakhna dykes from the northern Bastar craton. Petrographically and geochemically Lakhna dykes show variation from alkaline (trachyte), felsic (rhyolite) to mafic (dolerite) derivatives.…”

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

“…The reconstructions are highly speculative and sometimes technically incorrect mainly due to paucity of high-quality Late Palaeoproterozoic and Mesoproterozoic palaeomagnetic data. The data are insufficient even to draw an apparent polar wander (APW) path for any single craton 12 .…”

“…These results are restricted to the early-middle Palaeoproterozoic Era. The only study that pertains to the Late Palaeoproterozoic to Mesoproterozoic eras has been done by Pisarevsky et al 12 from dykes yielding a U-Pb age of 1466.4  2.6 Ma on the Bastar craton. The authors reported steep upward/downward magnetization directions from these dykes.…”