The evolution of deeply subducted carbonates and the formation of microdiamonds

深俯冲碳酸盐岩的演化和微金刚石的形成

• 批准号: 13640485
• 负责人: OGASAWARA Yoshihide
• 金额: $ 2.05万
• 依托单位: Waseda University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640485/
• 关键词: diamond; dolomite; Dolomite marble; fluid; Kokchetav; UHP metamorphic rock; deep subduction; Continental collision; ダイアモンド; チタン石; 離溶コース石; コクチェトフ超高圧変成帯

Deeply subducted carbonate rocks from the Kokchetav Massif, Kazakhstan were investigated in terms of the following subjects.1. Extremely high concentration of microdiamond found in dolomite marble. The contents of microdiamond are largely different domain by domain of the dolomite marble. The highest concentration of diamond were measured as about 2800 carat/ton.2. One of the samples showed the close relations between chemical zonation of garnet and the diamond distribution.3. The microdiamonds in dolomite marbles were classified into three types, S-type, R-type and T-type by their morphology.4. Microscopic observation, micro-Laue diffraction, laser Raman spectroscopy and micro cathode luminescence showed that the microdiamond formed at two stages.5. Micro -aue diffraction clarified the orientation of the rim and the core of S-type microdiamond. The rim is very fine grained transparent crystals and overgrew on the core at the 2^<nd> stage. The core of S-type diamond is a single crystal.6. The results suggested that the microdiamond in dolomite marble formed from fluids during both prograde and retrograde stage of UHP metamorphism.

本文对哈萨克斯坦Kokchetav地块深部俯冲碳酸盐岩进行了研究。在白云石大理石中发现了浓度极高的微金刚石。微金刚石的含量在不同的白云石云母中有很大的差异。钻石的最高浓度约为2800克拉/吨。其中一个样品显示石榴石的化学分带与金刚石的分布密切相关。白云岩大理岩中的微金刚石按其形态可分为s型、r型和t型3种类型。显微观察、微劳厄衍射、激光拉曼光谱和微阴极发光表明，微金刚石的形成分两个阶段。微光衍射明确了s型微金刚石的边缘和核心的取向。在2^<和>阶段，边缘是非常细粒的透明晶体，在核心上过度生长。5 . s型金刚石的核心是单晶。结果表明，白云石大理岩中的微金刚石是在超高压变质作用的前进和后退阶段形成的流体。

项目成果

Fukasawa et al.: "How deep were carbonates subdoctes into the manth-Unique UHP evidence in the marbles from Kokchetar"Fluid / Slab / Monthe Interactions and Ultrahigh-p minerals. 185-189 (2001)

Fukasawa 等人：“碳酸盐在科克切塔尔大理石中的独特超高压证据有多深”流体/板/蒙特相互作用和超高 p 矿物。

Katayama, Ohta, Ogasawara: "Mineral inclusions in zircon from diamond-bearing marble in the Kokchetav Massif, northern Kazakhstan"Europian Journal of Mineralogy. 14. 1103-1108 (2002)

Katayama、Ohta、Ogasawara：“哈萨克斯坦北部 Kokchetav 地块含金刚石大理石中的锆石中的矿物包裹体”《欧洲矿物学杂志》。

Ishida, Ogasawara, Ohsumi, Saito: "Two-stage growth of microdiamond in UHP dolomite marble from Kokchetav Massif, Kazakhstan"Journal of Metamorphic Geology. (in press). (2003)

Ishida、Ogasawara、Ohsumi、Saito：“来自哈萨克斯坦科克切塔夫地块的超高压白云石大理石中微金刚石的两阶段生长”变质地质学杂志。

Ishida, Ogasawara, Ohsumi, Saito: "Two-stage growth of microdiamond in UHP dolomite marble from Kokchetav Massif, Kazakhstan"Journal of Metamorphic Geology. 21(In press). (2003)

Ishida、Ogasawara、Ohsumi、Saito：“来自哈萨克斯坦科克切塔夫地块的超高压白云石大理石中微金刚石的两阶段生长”变质地质学杂志。

Mukherjee, Sachan, Ogasawara, Muko, Yoshioka: "Carbonate-bearing UHPM rocks from Tso-Morari region, Ladakh, India : petrological implication"International Geology Review. (In press). (2003)

Mukherjee、Sachan、Ogasawara、Muko、Yoshioka：“印度拉达克 Tso-Morari 地区的含碳酸盐 UHPM 岩石：岩石学意义”国际地质评论。