Paleomagnetism and Rock Magnetism of Early Cretaceous Rajmahal Basalts, NE India: Implications for Paleogeography of the Indian Subcontinent and Migration of the Kerguelen Hotspot

We present here new paleomagnetic and rock magnetic results from Rajmahal Traps (RT), India. The results are comprising of 350 standard specimens collected from 18 sites (90 samples). The detailed rock magnetic studies indicate that a Single Domain (SD) magnetite [Fe3O4] is the dominant magnetic carrier with ilmenite, pyrrhotite, and maghemite in the accessory form. The calculated Characteristic Remanent Magnetization (ChRM) directions yield a mean declination of 317.51 degrees; mean inclination of -61.92 degrees (alpha(95) = -3.6 degrees; k = -93.39). The obtained Virtual Geomagnetic Pole (VGP) position of the RT at similar to 117 Ma is 11.37 degrees N, 297.58 degrees E (62.42 degrees W) with A95 = 3.5 degrees, k = 99.99, dp = 4.33, dm = 5.58, and the calculated paleolatitude is at 43.1 degrees S indistinguishable from that of earlier works. This paleomagnetic pole of RT basalts has minimal effect of secular variation and comply with the Geocentric Axial Dipole (GAD) model. The VGP is plotted on synthetic Apparent Polar Wander Path (APWP) for India, constrained better, and agrees well with the previously reported poles. The postulation of migration of mantle plume and the global mantle circulations are tested, and the present study results are in accord with this, suggesting the southward migration of the Kerguelen hotspot (mantle plume) by at least 6 degrees.