FORMATION OF DIAMOND IN KIMBERLITE
#FORMATION OF DIAMOND IN KIMBERLITE Diamond Mining, Kimberly Town, South Afrika Formation of Kimberlite Kimberlites, named after the town of Kimberly, South Africa, where they were first described, are volcanic rocks that originate in Earth’s mantle. They are mined exclusively for diamonds. The photo shows the “Big Hole” at Kimberly. The Hole was mined from 1871 to 1914 and reached a depth of 240 m below the surface. Subsequently, it filled with water. Kimberlite eruptions are gas-powered explosive events. The magmas originate at depths of 150 to 450 km, deeper than other igneous rocks. Most kimberlites are in small vertical columns called kimberlite pipes although some rare sills are known. These pipes are the most important source of diamonds today. If kimberlite weathers and erodes, the diamonds may become concentrated in sedimentary deposits. Some kimberlites bring mantle xenoliths (pieces of mantle rock) to the surface; petrologists use these samples to study m...