Paleomagnetic results from the Singhbhum Craton, India: remagnetization, demagnetization, and complication

Abstract

We report a complicated magnetic fidelity through time in Singhbhum Craton, India, with new, geographically wide-spread and spatially detailed, paleomagnetic results. The Singhbhum Craton in eastern India is cross-cut by multiple generations of the so-called “Newer Dolerite” dykes. A previously published 1765 Ma paleomagnetic pole represents a useful constraint on the Singhbhum Craton during the amalgamation of the Columbia supercontinent whereas an older ~2763 Ma paleomagnetic pole is problematic. We present additional data from the 1765 Ma dykes that results in a grand mean paleomagnetic pole at 43◦N, 320◦E (A95 = 10◦, K = 17; N = 13). The 1765 Ma pole is supported by a positive baked contact test. Our additional data shows that paleomagnetic results from the 1765 Ma dykes are more complicated by magnetic overprints than originally reported. We also argue that the steep inclination paleomagnetic data from the Singhbhum Craton, previously assumed to represent a Neoarchean signal, are part of a complicated group whose magnetic age is uncertain. We establish a minimum age of 2250 Ma for connecting the Singhbhum and Dharwar cratons on the basis of published geochronology and our interpretation of paleomagnetic data in this paper. Paleomagnetic data from both cratons can be juxtaposed using a simple Euler pole rotation of the Singhbhum Craton relative to Dharwar.