xenolith

Outcrop-scale areas of gabbro within the Calais Quartz Diorite unit may be xenolithic or mingled material from the Staples Mountain and St.

The main pipe, which comprises the northern part of the body, is characterised by tuffistic serpentine kimberlite breccia, with a moderate amount of mantle component, and locally abundant large xenolithic blocks.

Whether these "fragments" are phenocrysts crystallized directly from the kimberlite melt or xenolithic inclusions of other rock types was a question which went unresolved for some decades.

Several xenolithic bodies of Pretoria group quartzite and shale occur; the largest and most southerly of these masses dips at an angle of 50 [degrees] to 60 [degrees] towards the south.