Palaeomagnetism of the Cretaceous Lamproites from Gondwana basin of the Damodar Valley in India and migration of the Kerguelen plume in the Southeast Indian Ocean

Abstract

The paper presents new palaeomagnetic results and reassesses complete set of published palaeomagnetic results on the lamproite intrusions in the Gondwana formations of the Eastern India. Altogether eleven sites register reliable characteristic magnetisations corresponding to the c. 110 Ma emplacement age of the lamproites. A mean ChRM is estimated with D=331.3°; I=−62.4° (α95=6.2°, k=55; N=11). The palaeomagnetic pole of λ=14.9°: Φ=287.6° (A95=8.4°) is established for the lamproites and it averaged the secular variation and confirms to the Geocentric Axial Dipole (GAD). The pole compares remarkably well with the grand mean pole reported for the Rajmahal traps that are attributed to represent location of the Kerguelen mantle plume head. The palaeolatitudes transferred to Rajmahal coordinates (25.05°: 87.84°) are situated ∼6° north of the present location of the Kerguelen hotspot location. The interpretations are consistent with earlier suggestions of southward migration of the plume based on palaeomagnetic results of Site 1138 of the ODP Leg 183 and with the predictions of numerical models of global mantle circulation.