Experimental Modeling of the Mantle–Slab Interaction in the Metal–Carbonate System, Conditions of Crystallization and Indicator Characteristics of Diamond
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2023-05-10 |
| Journal | Russian Geology and Geophysics |
| Authors | Yuri N. Palyanov, Yuliya V. Bataleva, Yuri M. Borzdov, Igor N. Kupriyanov, Denis V. Nechaev |
| Institutions | V.S. Sobolev Institute of Geology and Mineralogy, Novosibirsk State University |
| Citations | 4 |
Abstract
Section titled “Abstract”Abstract —Experimental studies aimed at determining the conditions for the formation of diamond and graphite as a result of the redox interaction of reduced mantle rocks and oxidized rocks of the slab in a wide temperature range, including the conditions of both “cold” and “hot” subduction, were carried out on a “split-sphere” multianvil high-pressure apparatus (BARS) in the (Fe,Ni)-(Mg,Ca)CO3 system, at 6.3 GPa and 800-1550 °C for 35-105 h, using the “sandwich” assembly. We have established that the interaction of Fe,Ni metal and carbonate is due to the creation and propagation of a redox front, at rates from 1.3 (800 °C) to 118 μm/h (1550 °C). At T < 1200 °С, this interaction leads to the formation of alternating reaction zones (from the reduced center to the oxidized periphery): metal → metal + wüstite/magnesiowüstite → magnesiowüstite + graphite ± Mg,Fe,Ca carbonates → magnesite + aragonite. In this case, in the reduced part of the samples, the formation of a Ni,Fe metal phase strongly enriched in Ni (up to 65-70 wt.% vs. the initial 10 wt.%) was recorded. At higher temperatures, the formation of Fe,Ni metal-carbon (≥1200 °C) and carbonate (≥1330 °C) melts was observed. We have found that the presence of nickel precludes the formation of carbides in the reduced part of the sample and ensures stable diamond crystallization at 1400-1550 °C both in metal-carbon and carbonate melts. Our experiments demonstrate that diamonds from the metal-carbon melt are characterized by inclusions of taenite and magnesiowüstite. The morphology of these diamonds is determined by the {111} layer-by-layer grown faces, and their indicator characteristics are nitrogen-vacancy and nickel-related (884 nm) centers at 1400 °C or nickel-nitrogen centers (S3, 598 nm, 727 nm, 746 nm, etc.) at 1550 °C. For diamonds formed in the carbonate melt, the morphology is determined by the {100} and {111} (vicinal-growth) faces; carbonates are identified as inclusions; and nitrogen-vacancy centers H3, NV0, and NV- are fixed in the photoluminescence spectra. Experiments show that the indicator of the metal-carbonate interaction temperature is the degree of structural perfection of graphite, which increases in the range of 800-1550 °C.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
Section titled “References”- 2022 - Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks [Crossref]
- 1994 - The generation of oxidized CO2-bearing basaltic melts from reduced CH4-bearing upper mantle sources [Crossref]
- 2015 - The role of rocks saturated with metallic iron in the formation of ferric carbonate-silicate melts: experimental modeling under PT-conditions of lithospheric mantle [Crossref]
- 2016 - Synthesis of diamonds with mineral, fluid and melt inclusions [Crossref]
- 2007 - Carbonates from the lower part of transition zone or even the lower mantle [Crossref]
- 1995 - The formation of diamond [Crossref]
- 2010 - Mineral inclusions in sublithospheric diamonds from Collier 4 kimberlite pipe, Juina, Brazil: subducted protoliths, carbonated melts and primary kimberlite magmatism [Crossref]
- 2000 - Spectroscopy of defects and transition metals in diamond [Crossref]
- 1999 - Diamonds from Wellington, NSW: Insights into the origin of eastern Australian diamonds [Crossref]
- 2007 - Raman spectroscopy of graphene and graphite: Disorder, electron-phonon coupling, doping and nonadiabatic effects [Crossref]