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Ophiolite-Hosted Diamond: A New Window for Probing Carbon Cycling in the Deep Mantle
- Source :
- Engineering, Vol 5, Iss 3, Pp 406-420 (2019)
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- As reported in our prior work, we have recovered microdiamonds and other unusual minerals, including pseudomorph stishovite, moissanite, qingsongite, native elements, metallic alloys, and some crustal minerals (i.e., zircon, quartz, amphibole, and rutile) from ophiolitic peridotites and chromitites. These ophiolite-hosted microdiamonds display different features than kimberlitic, metamorphic, and meteoritic diamonds in terms of isotopic values and mineral inclusions. The characteristic of their light carbon isotopic composition implies that the material source of ophiolite-hosted diamonds is surface-derived organic matter. Coesite inclusions coexisting with kyanite rimming an FeTi alloy from the Luobusa ophiolite show a polycrystalline nature and a prismatic habit, indicating their origin as a replacement of stishovite. The occurrence in kyanite and coesite with inclusions of qingsongite, a cubic boron nitride mineral, and a high-pressure polymorph of rutile (TiO2 II) point to formation pressures of 10–15 GPa at temperatures ∼1300 °C, consistent with depths greater than 380 km, near the mantle transition zone (MTZ). Minerals such as moissanite, native elements, and metallic alloys in chromite grains indicate a highly reduced environment for ophiolitic peridotites and chromitites. Widespread occurrence of diamonds in ophiolitic peridotites and chromitites suggests that the oceanic mantle may be a more significant carbon reservoir than previously thought. These ophiolite-hosted diamonds have proved that surface carbon can be subducted into the deep mantle, and have provided us with a new window for probing deep carbon cycling. Keywords: Ophiolite-hosted diamond, Coesite, Stishovite, Podiform chromitites, Mantle transition zone
- Subjects :
- Environmental Engineering
General Computer Science
Materials Science (miscellaneous)
General Chemical Engineering
Geochemistry
Energy Engineering and Power Technology
02 engineering and technology
engineering.material
010402 general chemistry
Ophiolite
01 natural sciences
Kyanite
Coesite
Transition zone
Moissanite
Amphibole
Stishovite
General Engineering
021001 nanoscience & nanotechnology
0104 chemical sciences
lcsh:TA1-2040
visual_art
engineering
visual_art.visual_art_medium
lcsh:Engineering (General). Civil engineering (General)
0210 nano-technology
Pseudomorph
Geology
Subjects
Details
- ISSN :
- 20958099
- Volume :
- 5
- Database :
- OpenAIRE
- Journal :
- Engineering
- Accession number :
- edsair.doi.dedup.....2233f1ae2c76e48f29dabb7e2545efd0