Paleomagnetism and rock magnetism of similar to 2.37-1.89 Ga dykes from the Western Dharwar craton, southern India: Implications for drift history through paleoproterozic

A study has been carried out using Paleomagnetism and rock magnetism as a proxy on dykes from Tiptur area in the late Archean Western Dharwar craton, southern India. 101 oriented block samples from 20 sites (10 sites -50 samples from Belagumba and 10 sites -51 samples from Navile) of NE-SW and NNW-SSE oriented dykes were collected and the results are presented here along with previously reported data on dyke swarms from Western as well as Eastern Dharwar craton. Measurement of magnetisation versus temperature curves yielded two types of thermo-magnetic curves which are nearly reversible and irreversible with magnetite as remanence carrier for both Belagumba and Navile dykes. The magnetic directions show two components, viz., six sites representing Belagumba dyke give mean declination of 269 degrees and mean inclination of - 38 degrees (Precision parameter (k) = 9, Circle of confidence (alpha 95) = 23 degrees) and nine sites from Navile dyke yielded mean declination of 302 degrees and mean inclination of - 21 degrees (k = 44, alpha 95 = 8 degrees). The corresponding paleopoles obtained at 6.09 degrees S, 325 degrees E (semi-axis of the ellipse of confidence (dp) = 16 degrees and semi-axis perpendicular to the great circle (dm) = 27 degrees) for Belagumba and 27 degrees N, 327 degrees E (dp = 4 degrees and dm = 8 degrees) for Navile respectively. The updated APWP for Dharwar craton from two poles from this study and six well constrained key paleopoles from 2.37 Ga to 1.89 Ga periods of previous studies suggests that Dharwar craton has a rapid drift rate from 26 degrees to 53 degrees paleolatitude along with a clockwise rotation (similar to 40 degrees) during 2235 Ma to 2216 Ma.