The mantle beneath the Kaapvaal Craton has undergone extensive metasomatism, particularly during kimberlite, carbonate-rich olivine lamproite, and Karoo plume-related magmatism. One population of micro-xenoliths in the Karowe kimberlite, Botswana, is characterized by dominant clinopyroxene + phlogopite. Some of these highly metasomatized rocks are directly in contact with depleted dunitic or harzburgitic lithologies in the same micro-xenolith (see image). These samples are ideal for studying metasomatic processes in the mantle on a mm to cm-scale.
The aim of this project is to reconstruct the evolution of this metasomatic suite. What metasomatic reactions took place, what type of fluid/melt percolated, at what PT conditions did this occur, and when did this metasomatic event happen? Is the fluid/melt enhancing diamond formation or resorbing diamonds? The Sr isotopic composition of clinopyroxene will additionally be used as a source tracer of the fluid/melt.
The project will include petrographic characterization of samples, electron microprobe mineral analysis, laser ablation ICP-MS trace element analysis, and Rb-Sr dating via TIMS.
In collaboration with Dr. Ingrid Chinn, De Beers Group of Companies
Advisors: Prof. Suzette Timmerman, Prof. Daniela Rubatto
University: BE