碳酸岩是地表出露相对较少的幔源岩石之一,通常呈岩脉、岩株、岩墙、岩锥等出露,主要产于裂谷环境。因易与沉积的碳酸盐岩及其变质的大理岩相混,经常被人们忽视。已有工作主要集中在它们与共生碱性岩的成岩模式上(Mitchell等,2005:Xu等,2007;Chakhmouradian等,2008),而对碳酸岩 Carbonatite is one of the mantle source rocks with relatively few surface exposures. It is usually exposed in dikes, rock formations, dykes and rock cones, and is mainly produced in the rift environment. Due to easy to mix with sedimentary carbonate rocks and metamorphic marble, it is often overlooked. Work has been mainly focused on the diagenetic patterns of these and symbiotic alkaline rocks (Mitchell et al., 2005: Xu et al., 2007; Chakhmouradian et al., 2008)