Animated reconstructions of the Late Cretaceous to Cenozoic northward migration of Australia, and implications for the generation of east Australian mafic magmatism: COMMENT

Animated reconstructions of the Late Cretaceous to Cenozoic northward migration of Australia, and implications for the generation of east Australian mafic magmatism: REPLY

“…Below we clarify our methodology in compiling these previous results, which, as shown by Musgrave and Schmidt (2019), was poorly explained. Some confusion may have arisen from references to "linear and longitudinal apparent polar wander paths (APWPs)" (Jones et al, 2017, p. 474) versus "linear and longitudinal reconstructions" (Jones et al, 2017, p. 466, 477-478).…”

“…We appreciate the opportunity to discuss our paper on the Cenozoic mafic magmatism of eastern Australia and potential relationships to plate motion and are thankful to Musgrave and Schmidt (2019) for bringing the uncertainties and inconsistencies of Jones et al (2017) to our attention. The comments from Musgrave and Schmidt (2019) focus on the paleomagnetic record of Australian plate motion, so, to begin, we note that Jones et al (2017) did not include new paleomagnetic data. Instead, the paper presented new 40 Ar/ 39 Ar results from east Australian mafic rocks and evaluated them in light of tectonic reconstruction circuits compiled by Seton et al (2012).…”

“…Nevertheless, the Torsvik et al (2012) global APWP indicates a period of slower northward velocity in the late Oligocene to early Miocene, similar to the longitudinal APWPs, but slightly postdating the bend in the east Australian seamount track. Musgrave and Schmidt (2019) commented primarily on how our reconstructions were determined, so below we clarify our methodology in compiling and interpreting previous results. When directly comparing APWPs and the GMHRF, reconstructed points were rotated using poles derived from the longitudinal APWP of Embleton and McElhinny (1982) and the "linear" APWP of Idnurm (1985).…”

“…Points were then individually overlain as projections onto the base figure, after Musgrave (1989). This method introduced a degree of error that may explain some of the variation between our results and those of Musgrave and Schmidt (2019), and in some cases the projections appear to have been misaligned. Figure 11A in Jones et al (2017) has an error in the location of the longitudinal 50 Ma point, and we thank Musgrave and Schmidt (2019) for drawing this to our attention.…”