Comparing Paleomagnetic Study Means With Apparent Wander Paths: A Case Study and Paleomagnetic Test of the Greater India Versus Greater Indian Basin Hypotheses

This paper discusses the framework for comparing independent study means (SMs) with averages of aggregated study mean paleomagnetic poles, hereafter referred to as reference poles, contributing to continental or global apparent polar wander paths (GAPWP). Paleomagnetists typically compare individual SMs to these population means to compute latitudinal displacements or rotations with uncertainties estimated by comparing A(95)'s. Using this comparison statistic, more than half of the population of reference SMs contributing to a GAPWP fall at an angular distance that is greater than their combined uncertainties. Two approaches are presented that yield similar results based on different rationales and comparison statistics. Common to both approaches is K-95,K-GAPWP, the angular distance within which 95% of poles contributing to an APWP mean fall. One approach combines K-95,K-GAPWP and the A(95,SM) of the independent study mean that can only be judged to be significantly displaced if the angular difference with the GAPWP mean exceeds their combined uncertainty. The second approach uses K-95,K-GAPWP as the best estimate of total error of each study mean, which when combined with uncertainty of the GAPWP mean, A(95,GAPWP), defines the angular difference that the independent study mean needs to exceed to be judged to be significantly displaced from a GAPWP mean. These comparison statistics are used to assess paleomagnetic support for Greater Indian Basin hypothesis for the paleogeographic evolution of the northern margin of India prior to collision with Asia. The Greater Indian Basin hypothesis is not supported based on these more rigorous criteria.