鲁西蒙阴地区含金刚石金伯利岩的岩浆侵入序列及成矿模式

The magmatic intrusive sequence and the metallogenic model of diamondiferous kimberlite in the Mengyin area, western Shandong

鲁西蒙阴地区是我国金刚石原生矿重要产地之一,其含金刚石金伯利岩命名为常马庄单元。本文对该区金伯利岩地质特征进行了梳理,按岩石命名原则对该地区含金刚石金伯利岩不同岩石类型进行了重新划分和命名,共划分了细斑微粒金伯利玢岩类、粗斑细微粒金伯利玢岩类和含碎屑细斑或中细斑微粒金伯利玢岩类3个岩石类型和13个亚类型,同时首次从早至晚划分了细斑微粒金伯利玢岩类→含围岩角砾中细斑微粒金伯利玢岩类→粗斑细微粒金伯利玢岩类的侵入序列。通过对前人研究资料的综合分析并结合野外实地考察认为:以前套用南非金伯利岩型金刚石原生矿中心式火山喷发型成矿模式作为蒙阴地区含金刚石金伯利岩的成矿模式不符合该区实际地质特征。提出了该区金刚石金伯利岩新的成矿模式为中心式—裂隙式复合潜火山隐爆岩浆序次侵入充填型岩浆侵入角砾岩筒及其伴生的岩脉、岩床模型。

The Mengyin area of western Shandong Province is one of the important producing areas of primary diamond in China. This paper introduces the geological characteristics of kimberlite, reclassifies and renames different types of diamondiferous kimberlite in this area. Based on the principles of rock naming, three rock types, 13 subtypes of the fine-grained kimberley porphyrite, coarse-grained fine-grained kimberley porphyrite, and the clastic fine-grained or medium-sized fine-grained kimberley porphyrite were identified. At the same time, the intrusion sequence of the fine-grained kimberley porphyrite, the surrounding rock, angular fine-grained medium-sized fine-grained kimberley porphyrite, the coarse-grained fine-grained kimberley porphyrite is sequentially divided for the first time. Based on the comprehensive analysis of previous research data and field investigation, it is concluded that the previous metallogenic model of diamondiferous kimberlite in the Mengyin area is not consistent with the actual geological characteristics. The new metallogenic model of the Paleozoic Middle Ordovician diamond kimberlite in this area is the central fracture type compound subvolcanic crypto explosion with sequential magma intrusion filling. The magmatic intrusion in the breccia tube and its associated dyke and bed model are constructed.