Volcanic pipe Volcanic pipe Volcanic pipes are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of "diatreme". Volcanic pipes are composed of a deep, narrow cone of solidified magma (described as "carrot-shaped"), and are usually largely composed of one of two characteristic rock types — kimberlite or lamproite. These rocks reflect the composition of the volcanoes' deep magma sources, where the Earth is rich in magnesium. Volcanic pipes are relatively rare. They are well known as the primary source of diamonds, and are mined for this purpose. Volcanic pipes form as
Buffalo Head Hills kimberlite field in mudstones that are interbedded with some of the kimberlite deposits are consistent with the Late Cretaceous age. The BHH kimberlite pipes cover areas ranging from one to . They represent maar-style volcanoes which have a vertical-walled volcanic crater of explosive origin, surrounded by a low rim of ejecta and filled with water. Pyroclastic fall and surge are the two volcanic mechanisms of deposition. There are also deposits formed by hydraulic reworking of kimberlite from tephra cones and/or extra-crater fall and surge deposits. The pyroclastic fall deposits are poorly sorted and massive, while the surge deposits are better sorted, fine