Understanding the range of transport styles recorded by kimberlite deposits is key to describing the type and style of eruptions, the growth of cones and craters, and the distribution, geometry and structure of the deposits that make up kimberlite volcanoes. In an economic context, building a clear picture of the processes that shape deposits is essential for selecting exploration targets and evaluating the grade and value of diamond-bearing kimberlites.

The form of the kimberlite volcano is determined when the magma arrives at or just below the surface. In shallow vents the erupted mixture rapidly expands to form dense to dilute pyroclastic density currents and convecting plumes, but as vents deepen transport is dominated by upward-directed high particle-concentration jets of debris along with downward-directed collapse as material is excavated from depth. Deposits that have experienced limited sorting such as well-mixed deposits in diatremes or weakly fragmented spatter likely have fairly homogeneous diamond grades, whereas better-sorted fall or density current deposits probably have highly variable diamond grades.

Evaluating the full range of transport styles recorded in kimberlite deposists is crucial to accurate resource evaluation. Contact us to find out how we can add value to your geology program.

McClintock, M., White, J.D.L. (2008) The importance of the transport system in shaping the growth and form of kimberlite volcanoes. 9th International Kimberlite Conference: Session 9IKC-02, on Wednesday, 13 August 2008, 10:00 am

McClintock, M. & White, J.D.L. (2006) Large phreatomagmatic vent complex at Coombs Hills, Antarctica: Wet, explosive initiation of flood basalt volcanism in the Ferrar-Karoo LIP. Bulletin of Volcanology 68: 215-239