Multiple core growth structure and nitrogen abundances of diamond crystals from Shandong and Liaoning kimberlite pipes, China
Multiple core growth structure and nitrogen abundances of diamond crystals from Shandong and Liaoning kimberlite pipes, China
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DOI：
10.1127/0935-1221/2012/0024-2230
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发表时间：
2012-08
影响因子：
2.1
通讯作者：
Taijin Lu;Hua Chen;Zhi-li Qiu;Jian Zhang;W. Ran;Jie Ke;I. Sunagawa;R. Stern;T. Stachel
中科院分区：
文献类型：
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作者：
Taijin Lu;Hua Chen;Zhi-li Qiu;Jian Zhang;W. Ran;Jie Ke;I. Sunagawa;R. Stern;T. Stachel
山东和辽宁金伯利岩的金刚石晶体显示出明显的“种子状”多核生长结构，具有多阶段的生长历史。阴极发光和DiamondView图像显示，金刚石的核心部分被“种子状”沉淀或更小的核心所占据，这可能是由长方体生长机制形成的被吸收的早期晶体。在核部与八面体层交界处，氮浓度从核部的几百ppm骤降至~1 ppm，表明地幔地球化学生长环境发生了根本性的变化。这与δ 13c分带趋势由向外升高转为向外降低有关，证实了生长条件发生了变化。
Diamond crystals from the Shandong and Liaoning kimberlites, China, display a distinct “seed-like” multiple core growth structure with multi-stage growth history. Cathodoluminescence and DiamondView images revealed that the core portion of the diamonds is occupied by a “seed-like” precipitated or smaller core which could be a resorbed early crystal formed by a cuboid growth mechanism. At the boundary between the core portion and the octahedral layers, the nitrogen concentration drops abruptly to ~1 ppm from a few hundreds of ppm in the core portion, suggesting a fundamental change in geochemical growth environments in the mantle. This is associated with a switch in zoning trends in δ 13 C from outward increasing to outward decreasing values, confirming that a change in growth conditions occurred.