Kimberlitgänge

Kimberlitgänge are igneous intrusions composed of kimberlite, a rare and ultrabasic volcanic rock. They are typically found in ancient continental crust and are often associated with diamond deposits. Kimberlite is characterized by its ultramafic composition, rich in magnesium and iron, and its distinctive texture, often containing xenocrysts (crystals foreign to the kimberlite itself) and xenoliths (rock fragments engulfed by the magma). The magma originates deep within the Earth's mantle, at depths of 150-300 kilometers, and ascends rapidly to the surface. This rapid ascent is crucial for preserving diamonds, which form under high pressure and temperature conditions and would otherwise revert to graphite if subjected to slower ascent and decompression.

Kimberlitgänge are geologically significant because they are the primary source of mined diamonds. The presence of diamonds within kimberlite is a testament to the extreme conditions and processes occurring deep within the Earth's mantle. These intrusions often form pipe-like or dike-like structures, with dikes being more linear and often shallower than the more voluminous pipes. The exploration for kimberlite deposits involves geological surveys, geophysical methods, and geochemical analysis, as kimberlite often occurs in specific geological settings and has a distinct chemical signature. While kimberlite is the main source of diamonds, other diamond-bearing rocks, such as lamproites, also exist, but kimberlite remains the most economically important. The formation of kimberlitgänge is a rare geological event, making both the rocks themselves and the diamonds they carry highly valued.