The mineralogy of Ca-rich inclusions in sublithospheric diamonds
The mineralogy of Ca-rich inclusions in sublithospheric diamonds
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DOI：
10.1134/s0016702916100116
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发表时间：
2016-10
影响因子：
0.8
通讯作者：
D. Zedgenizov;A. Ragozin;V. Kalinina;H. Kagi
中科院分区：
文献类型：
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作者：
D. Zedgenizov;A. Ragozin;V. Kalinina;H. Kagi
本文讨论了超深部（岩石圈下）钻石中富钙包裹体的矿物学特征。结果表明，多数富钙多数型石榴石具有变质（榴辉）亲和性。观测到的主微量元素组成的变化与原岩组成的变化以及与熔体相互作用过程中富集或富集程度的变化是一致的。超深部金刚石中Ca矿物包裹体的主微量元素组成表明，它们是由过渡带深部俯冲洋壳中榴辉岩体部分熔融形成的Ca-碳酸盐岩熔体结晶而成。超深部金刚石中墨长石或CAS包裹体的赋存可以作为变质橄榄岩和变质地幔岩性与碱性碳酸盐岩熔体相互作用的矿物学指标。与超深钙矿物相关的碳酸盐包裹体的发现不仅为它们在金刚石形成过程中的作用提供了额外的支持，而且有助于确定参与全球碳循环的额外地幔储层。
This paper discusses mineralogy of Ca-rich inclusions in ultra-deep (sublithospheric) diamonds. It was shown that most of the Ca-rich majoritic garnets are of metabasic (eclogitic) affinity. The observed variation in major and trace element composition is consistent with variations in the composition of the protolith and the degree of enrichment or depletion during interaction with melts. Major and trace element compositions of the inclusions of Ca minerals in ultra-deep diamonds indicate that they crystallized from Ca-carbonatite melts that were derived from partial melting of eclogite bodies in deeply subducted oceanic crust in the transition zone or even the lower mantle. The occurrence of merwinite or CAS inclusions in ultra-deep diamonds can serve as mineralogical indicators of the interaction of metaperidotitic and metabasic mantle lithologies with alkaline carbonatite melts. The discovery of the inclusions of carbonates in association with ultra-deep Ca minerals can not only provide additional support for their role in the diamond formation process but also help to define additional mantle reservoirs involved in global carbon cycle.