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Kimberlite occurs in the Earth's crust in vertical structures known as kimberlite pipes, as well as igneous dykes and can also occur as horizontal sills. Kimberlite pipes are the most important source of mined diamonds today. The consensus on kimberlites is that they are formed deep within Earth's mantle.
The ML rocks are not considered to be archetypal kimberilte and have been variously classified as alkaline ultramafic rocks, hybrid alkaline ultramafic rocks, alkali olivine basalt and basanite; they are difficult to classify because of strong clay alteration that has obliterated most of their original mineralogy.
The ML pipes form part of the Northern Alberta kimberlite province, along with the nearby Birch Mountains kimberlite field and the Buffalo Head Hills kimberlite field.They were discovered in 1989-90 just north of Mountain Lake (55.456291n 117.714510w), which lies about 75 km (47 mi) northeast of Grande Prairie, Alberta.
Lamproite pipes operate similarly to kimberlite pipes, except that the boiling water and volatile compounds contained in the magma act corrosively on the overlying rock, resulting in a broader cone of eviscerated rock (the ejection of this rock also forms a tuff ring, like kimberlite eruptions). This broad cone is then filled with volcanic ash ...
Aerial view of the Moses Rock Dike diatreme in San Juan County, Utah [1] A diatreme , sometimes known as a maar-diatreme volcano, is a volcanic pipe associated with a gaseous explosion. When magma rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater , rapid expansion of heated water vapor and volcanic ...
The country has the highest concentration of kimberlite bodies in the world—a total of more than 400, including 343 dikes, 39 pipes and 23 blows. Northern Lesotho has an average of one kimberlite body for every 10 square kilometers. In spite of the large deposits, very few sites are mined and research is ongoing into alluvial deposits.
Since then it has accumulated about 40 metres (130 ft) of water, leaving 175 metres (574 ft) of the hole visible. Once above-ground operations became too dangerous and unproductive, the kimberlite pipe of the Alyrick Mine was also mined underground by Cecil Rhodes' De Beers company to a depth of 1,097 metres (3,599 ft). [5]
It is within the Lake Timiskaming Structural Zone which contains over 50 kimberlite pipes, several of which are diamondiferous. [1] The Lake Timiskaming kimberlite field formed about 147 million years ago when the North American Plate moved westward over the long-lived New England hotspot , also referred to as the Great Meteor hotspot.