金伯利岩

产地：山东省蒙阴县

特征：

金伯利岩（Kimberlite）是一种偏碱性的超基性岩。是具斑状结构和（或）角砾状构造的云母橄榄岩。因1887年发现于非洲金伯利（Kimberley）而得名。旧称角砾云母橄榄岩。多呈黑、暗绿、灰等色。1887年发现于南非的金伯利（Kimberley），故名，旧称角砾云母橄榄岩。是产金刚石的最主要火成岩之一。常成群出现，著名的南非金伯利岩就是由十多个著名的岩筒组成的岩筒群。其中以具斑状结构且富含颗粒粗大橄榄石的金伯利岩含金刚石较富，而呈显微斑状结构，富含金云母的金伯利岩，含金刚石贫。

其时代，以白垩纪为主。金伯利岩为包括火山角砾岩（或凝灰岩）到浅成侵入岩的一套岩石。常见类型有凝灰质金伯利岩、角砾状金伯利岩及斑状金伯利岩等。金伯利岩主要分布在地壳构造运动的稳定地区，多呈岩筒、岩床、岩墙产出。中国山东、辽宁、新疆和田、澳大利亚昆士兰州与北领地地区等均有产出，呈岩脉状和火山喉管相等浅成岩体。

采集人：陈勇

Kimberlite

Provenance: Mengyin, Shandong, China

Characteristics:

Kimberlite is an igneous rock best known for sometimes containing diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.70g) diamond called the Star of South Africa in 1869 spawned a diamond rush, eventually creating the Big Hole.

Kimberlite occurs in the Earth's crust in vertical structures known as kimberlite pipes as well as igneous dykes and sills. Kimberlite pipes are the most important source of mined diamonds today. The consensus on kimberlites is that they are formed deep within the mantle. Formation occurs at depths between 150 and 450 kilometers (93 and 280 mi), potentially from anomalously enriched exotic mantle compositions, and they are erupted rapidly and violently, often with considerable carbon dioxide and other volatile components. It is this depth of melting and generation which makes kimberlites prone to hosting diamond xenocrysts.