How are Diatremes formed?
Diatreme is a general term used to describe a volcanic vent or pipe that formed when magma was forced through flat-lying sedimentary rock. The explosive energy of magmas with high dissolved gas contents allowed the magma to be forced through the rocks to form an expanded vent.
What type of volcano is kimberlite pipes?
Diamonds are brought to the surface from the mantle in a rare type of magma called kimberlite and erupted at a rare type of volcanic vent called a diatreme or pipe.
What is a kimberlite tube?
Carrot-shaped volcanic pipes rising from the upper mantle 100-300km beneath the crust. They are formed through the high-pressure eruption of kimberlite magma, which expands and breaks rock as it reaches the crust. Kimberlites often contain diamonds, which require an extreme amount of pressure to form.
What is another name for a volcanic pipe?
Volcanic pipes or volcanic conduits are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of diatreme.
Where is kimberlite rock found?
Generally speaking, kimberlites are found only in cratons, the oldest surviving areas of continental crust, which form the nuclei of continental landmasses and have remained virtually unchanged since their formation eons ago.
What is aa geology?
‘A’ā (pronounced “ah-ah”) is a Hawaiian term for lava flows that have a rough rubbly surface composed of broken lava blocks called clinkers. The incredibly spiny surface of a solidified ‘A’ā flow makes walking very difficult and slow.
What causes kimberlite pipes?
Mined diamonds that originate in the mantle are created when heat and pressure transform carbon. The mantle is nearly 100 miles below the Earth’s surface, and gems that come from the mantle are brought to the surface by kimberlite pipes, which are formed by deep-source volcanic eruptions.
What is kimberlite and how is it formed?
Kimberlite pipes are created as magma flows through deep fractures in the Earth. The magma inside the kimberlite pipes acts like an elevator, pushing the diamonds and other rocks and minerals through the mantle and crust in just a few hours.
How do kimberlite pipes form?
How did kimberlite volcanoes get their name?
Kimberlite is an igneous rock, which sometimes contains diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.70 g) diamond called the Star of South Africa in 1869 spawned a diamond rush and the digging of the open-pit mine called the Big Hole.
What is kimberlite and how did it get its name?
How big is the Diatreme facies of a kimberlite?
From The earth story. ♦ 2) Diatreme Facies: The diatreme facies in kimberlite is characterized by a carrot shaped body with near circular or elliptical outline on the surface and steeply dipping (80°-85°) walls. These facies sometimes may exceed 2 km in depth.
Where did the Kimberlite Diamond get its name?
It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.70 g) diamond called the Star of South Africa in 1869 spawned a diamond rush and the digging of the open-pit mine called the Big Hole.
Which is the best example of a diatreme?
Examples of diatremes include the Blackfoot diatreme and Cross diatreme in British Columbia, Canada. Diatremes are sometimes associated with deposition of economically significant mineral deposits such as kimberlite magma, which originates in the upper mantle.
How are the different types of kimberlites classified?
Historically, kimberlites have been classified into two distinct varieties, termed “basaltic” and “micaceous” based primarily on petrographic observations. This was later revised by C. B. Smith, who renamed these divisions “group I” and “group II” based on the isotopic affinities of these rocks using the Nd, Sr and Pb systems.