Kimberlites are believed to be very volatile-rich magma, which fast ascent and explosive emplacement is fueled by volatiles. However, kimberlites offer us little direct evidence about the behavior of volatiles during the emplacement. At what depth fluids exsolve from kimberlite magma? How the composition of fluids changes during the ascent? When does fluid separate from the melt during the emplacement? How fluids effect the emplacement mechanism and kimberlite geology? Diamonds can help us to answer some of these questions. Dissolution surface features on diamonds are good indicators of the composition of kimberlitic fluid.
Potential student research projects can involve or combine the following studies:
- Using resorption features of natural diamonds from geologically-controlled samples examine how composition of kimberlitic fluid changes with depth in a kimberlite pipe and between different magma phases filling the same pipe; examine composition of magmatic fluid as recorded by diamond surface in magmatic and pyroclastic kimberlites of different emplacement modes.
- Experimental study of diamond resorption morphology at pressure corresponding to the last 10 km of kimberlite ascent. The study will examine which diamond features are particular useful in identification of near-surface resorption and will use resorption features on natural diamond to test existing models of fluid exsolution from kimberlite magma.
- Experimental study of diamond resorption at mantle conditions. What metasomatic processes and agents resorb diamonds in different mantle lithologies? What is the ore-forming process of diamond growth in the mantle.
- Study of dissolution rates of mantle minerals carried by kimberlite magma to the surface and estimation of kimberlite ascent rates.