A Neoproterozoic Geomagnetic Field Reversal from the Kurnool Group, India: Implications for Stratigraphic Correlation and Formation of Gondwana

The Proterozoic Cuddapah Supergroup is predominantly of normal magnetization but has a reversely magnetized level coinciding with the Srisailam Quartzite at the top of the succession. The Kurnool Group overlies the Cuddapah Supergroup with an unconformity and we present palaeomagnetic results from the Kurnool Group members comprising the Banganapalli Quartzite and the Narji Limestone. The Neoproterozoic Banganapalli Quartzite carries stable normal and reverse magnetizations suggesting a geomagnetic field reversal at the time of its formation. The Narji Limestone is normally magnetized. A similar magnetization to that in the Banganapalli Quartzite is reported -1000km away in the Baghain Sandstone of the Vindhyan Supergroup. A possible correlation is made between Cuddapah Supergroup and Kurnool Group with the Vindhyan Supergroup. Based on palaeomagnetic poles, palaeolatitudes, palaeoclimatic and structural evidence it is suggested that India and Australia collided possibly during Neo-Proterozoic times in an attempt to form larger Gondwana.