钾镁煌斑岩: 优质金刚石主要载体与幔源流体活动标志. (Chinese)

Lamproites: The Main Carrier of High-quality Diamond and the Marker of the Activity of Mantle Source Fluids. (English)

Being a special volcanogenic or ultrabasic rock, lamproite is an important deep source rock and a symbolic product of the deep-seated magmatic activity. It can be used as a window to understand the mantle and as another kind of diamond host rock after kimberlite, which has been extensively studied. Globally, lamproites host some of the best diamonds, such as Argyle in western Australia. Lamproites in China are mainly distributed in Hunan, Guizhou, Yinniugou, Shanxi, Dajingtou, Shandong, Dahongshan, Hubei, and Keliyang in the western Kunlun Mountains. Comprehensive analysis has shown that lamproite is mainly distributed near the deep, large faults. Lamproites in China are contained in the Duyun–Guiyang–Tongren–Huaihua deep fault on the western margin of Jiangnan anteclise, the Changde–Anren deep fault, and the Tanlu fault zone. Primary diamonds are found in the lamproites in Maping, Zhenyuan, Guizhou, Yunyingwo, Ningxiang, Hunan, Dajingtou, Pingyi, and Shandong. The potential of lamproites in diamond mineralization needs to be further studied, especially the lamproite belts in Hunan-Guizhou and Tan–Lu Fault. The indicator minerals of lamproite are titanium-rich aluminum-poor phlogopite, potassic richterite, magnesite olivine, pyrope, chrome-spinel, chromite, etc. The chromite groups S1 and S2 which are aluminum-poor and magnesium-rich is indicative of the formation of diamond in lamproite. The activity of lamproite in China is multi-stage, among which the stage of Late Jurassic to Early Cretaceous (147–100 Ma) belongs to the important metallogenic period of diamond-bearing lamproite and related Au-rare earth element minerals in China. [ABSTRACT FROM AUTHOR]

钾镁煌斑岩是一类较为特殊的火山成因或浅成的超基性岩, 是一种重要的深源岩石, 是深源岩浆 活动的标志性产物, 可作为了解地幔信息的窗口, 也作为继金伯利岩之后的另一种金刚石寄主岩被持续关 注。全球最优质的金刚石产于钾镁煌斑岩中, 主要分布于西澳阿盖尔等地。中国钾镁煌斑岩主要分布于黔 湘一带、山西饮牛沟、山东大井头、湖北大洪山和西昆仑克里阳地区, 综合分析认为, 钾镁煌斑岩主要分布 于深大断裂附近, 中国钾镁煌斑岩受江南台隆西缘的都匀—贵阳—铜仁—怀化深断裂、常德—安仁深断裂 以及郯庐断裂带等深大断裂带控制; 贵州镇远马坪、湖南宁乡云影窝、山东平邑大井头等钾镁煌斑岩有原 生金刚石产出, 钾镁煌斑岩的金刚石成矿潜力仍然有待深入研究, 尤以湘黔钾镁煌斑岩带、郯庐断裂带大井 头等地可望突破。钾镁煌斑岩的标志性矿物有富钛贫铝金云母、钾碱镁闪石、镁橄榄石、镁铝榴石、铬尖 晶石、铬铁矿等。其中 S1、S2 组贫铝富镁铬铁矿对钾镁煌斑岩中金刚石的形成有指示意义。中国钾镁煌 斑岩活动具多期性, 其中晚侏罗世—早白垩世(147—100 Ma)时期属于中国含金刚石钾镁煌斑岩和相关的金 -稀土等金属矿产的重要成矿时期。 [ABSTRACT FROM AUTHOR]

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