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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.
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 ...
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.
The kimberlite is intruded into volcanic rocks of the Proterozoic Hemlock Formation. The exposed material is grayish green to reddish, iron stained highly weathered and consists of disaggregated rubbly fragments up to 10 inches (250 mm). It is generally accepted that the pipe was emplaced about 180 million years ago.
Deep beneath the BHH kimberlite field lies a 2.0 to 2.4 billion year old Precambrian craton called the Buffalo Head terrane, which has no exposure at surface.The Precambrian craton is overlain by about 1,600 m (5,200 ft) of Paleozoic and Mesozoic sedimentary rocks, which are covered by as much as 200 m (660 ft) of unconsolidated glacial and post-glacial sediments of Quaternary age.
The Birch Mountains kimberlite field is a cluster of kimberlitic volcanic pipes or diatremes in north-central Alberta, Canada that were emplaced during a period of kimberlitic volcanism in the Late Cretaceous epoch. [1] As of 2011, 8 diatremes had been discovered in the field, and diamonds and microdiamononds had been recovered during sampling ...
The area is composed of 18 kimberlite pipes of the Attawapiskat kimberlite field, 16 of which are diamondiferous, the Victor Mine sits on top of the Victor pipe and mines from Victor Main and Victor Southwest which have appeared close enough to the surface to be used in an open-pit mine.