Mantle temperature, lithospheric thickness and dynamic topography: decoding the secrets of volcanic rocks

Abstract: Earth's topography is maintained by a complex interplay of tectonic forcing, isostasy and mantle convection. While tectonic and isostatic processes are fairly well understood, the contribution of dynamic topography often remains difficult to quantify. I will show that we can use the trace element chemistry of intraplate basalts as a tool to estimate the role and mechanism of dynamic uplift. Upper mantle temperatures and lithospheric thickness calculated from volcanic data agree well with independent seismological estimates. From these results, the present-day state of the upper mantle can be derived and the importance of dynamic topography tested. Since volcanic rocks are preserved throughout the geological record, this tool could help illuminate temporal as well as spatial variations of mantle temperature and lithospheric thickness.