Kimberliittien

Kimberlite is a type of intrusive igneous rock that is commonly associated with diamond deposits. It is named after the town of Kimberley in South Africa, where the first commercial diamond discoveries were made in the late 19th century. Kimberlite rocks are formed when magma from the Earth's mantle rises to the surface through a volcanic vent or pipe, bringing with it minerals and rocks that have been transported from great depths.

The characteristic distinguishing feature of kimberlite is its coarse-grained texture, which is composed of phlogopite, shards of mantle peridotites, garnets, and other minerals. The rocks are dark green to brown in color and have a characteristic vesicular texture, with numerous gas bubbles preserved from the explosive release of magma. Kimberlite pipes can be several kilometers high and wide, and are usually centered over ancient cratons or areas of anomalous geology where the Earth's crust is thin.

Kimberlite rocks contain a variety of economic minerals, including diamonds, but also other oxide and sulfide minerals. Diamond concentrations are often found in the fine-grained micaceous gneisses and microgranites at the margins of kimberlite pipes, while other economic minerals such as chromite, garnet, and magnetite are found in the coarse-grained rock. Despite being known for their economic potential, kimberlite rocks have also provided valuable information for geologists and petrologists studying the Earth's mantle.

The study of kimberlite is crucial for understanding the Earth's mantle and the geological processes that have shaped the Earth's surface over millions of years. The findings from kimberlite research have advanced our knowledge on plate tectonics and the role of the mantle in the Earth's processes.