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In kimberlite pipes, the eruption ejects a column of overlying material directly over the magma column, and does not form a large above-ground elevation as typical volcanoes do; instead, a low ring of ejecta known as a tuff ring forms around a bowl-shaped depression over the subterranean column of magma. Over time, the tuff ring may erode back ...
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 NAKP kimberlite fields are located about 350 km (220 mi) to 450 km (280 mi) north to northwest of Edmonton in an area bounded by 55° and 57°N latitude and 115° and 118°W longitude. The area lies within the Canadian boreal forest and is sparsely settled.
The reworked kimberlite is well sorted, distinctly bedded, and contains abraded olivine grains. Multiple layers of pyroclastic and reworked kimberlite separated by layers of marine mudstone are present at some pipes. These represent a series of discrete kimberlite eruption events separated by quiescent periods during which the muds were ...
The mine was the first successful commercial non alluvial diamond mine not located on a kimberlite pipe. The pipe is named "AK-1", although it is commonly simply called the "Argyle pipe". The volcanic pipe is a diatreme, composed of olivine lamproite, present as tuff and lava. Peripheral volcanic facies suggest the lamproite eruption formed a maar.
Even within volcanology, the term has been used more generally by some than others, and in kimberlite terminology continues to be contentious. [2] A current geological understanding is that diatreme describes the overall structure cut into the substrate (some have used the term “pipe” for this hence the common term volcanic pipe). [2]
The Birch Mountains kimberlite field consists of eight kimberlite pipes known as Phoenix, Dragon, Xena, Legend and Valkyrie, dating approximately 75 million years old. [54] The Buffalo Head Hills kimberlite field was dominated by explosive kimberlite volcanism from 88 million years ago to 81 million years ago, forming maars . [ 51 ]
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 ML south pipe ...