TY - JOUR

T1 - Raman Spectroscopic Study and Isotopic Composition of Graphite Inclusions in HP Xenoliths From “Eclogitovaya” Pipe (The Eastern Pamir)

AU - Podugolnikova, Ekaterina E

AU - Korsakov, Andrey V

AU - Mikhailenko, Denis S

AU - Odinaev, Sharifjon А

AU - Gadoev, Mustafo L

N1 - This study was supported by a grant from the Russian Science Foundation (RSF 24\u201017\u201000164).

PY - 2025/6/25

Y1 - 2025/6/25

N2 - Graphite is a common mineral occurring in different metamorphic rocks, including high/ultrahigh-temperature and high/ultrahigh-pressure rocks. Raman spectroscopic studies combined with carbon isotope composition may highlight the carbon source (crustal or mantle) and PT conditions of graphite crystallization. In the present study, seven graphite-bearing samples of felsic granulite xenoliths from the “Eclogitovaya” pipe (the Eastern Pamir, Tajikistan) have been studied by Raman spectroscopy and analyzed its carbon isotope composition. Graphite crystals occur in the matrix as well as inclusions in rock-forming minerals (e.g., garnet and kyanite), indicating their simultaneous crystallization. The graphite formed as a result of the metamorphic transformation of carbonaceous material (δ13С ranges from −14.5‰ to −20.1‰) originally present in the rocks during subduction. Structural analysis of intact graphite inclusions in garnet revealed rims of disordered graphite surrounding well-ordered graphite cores. Composite inclusions consisting of disordered graphite, well-ordered graphite, and CO2 were also observed. However, any evidence for precipitation of disordered graphite from fluid has not been found. It is likely that the origin of disordered graphite in the Eastern Pamir granulite xenoliths is attributed to the stress at the graphite–garnet interface during the rapid exhumation of the xenoliths.

AB - Graphite is a common mineral occurring in different metamorphic rocks, including high/ultrahigh-temperature and high/ultrahigh-pressure rocks. Raman spectroscopic studies combined with carbon isotope composition may highlight the carbon source (crustal or mantle) and PT conditions of graphite crystallization. In the present study, seven graphite-bearing samples of felsic granulite xenoliths from the “Eclogitovaya” pipe (the Eastern Pamir, Tajikistan) have been studied by Raman spectroscopy and analyzed its carbon isotope composition. Graphite crystals occur in the matrix as well as inclusions in rock-forming minerals (e.g., garnet and kyanite), indicating their simultaneous crystallization. The graphite formed as a result of the metamorphic transformation of carbonaceous material (δ13С ranges from −14.5‰ to −20.1‰) originally present in the rocks during subduction. Structural analysis of intact graphite inclusions in garnet revealed rims of disordered graphite surrounding well-ordered graphite cores. Composite inclusions consisting of disordered graphite, well-ordered graphite, and CO2 were also observed. However, any evidence for precipitation of disordered graphite from fluid has not been found. It is likely that the origin of disordered graphite in the Eastern Pamir granulite xenoliths is attributed to the stress at the graphite–garnet interface during the rapid exhumation of the xenoliths.

KW - Raman spectroscopy

KW - disordered graphite

KW - felsic granulites

KW - the Dunkeldik volcanic field

UR - https://www.mendeley.com/catalogue/4acee31d-4f04-353e-82b8-a5156459f855/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-105008812603&origin=inward&txGid=4408c76c5738cab468f06b7447a100b1

U2 - 10.1002/jrs.70011

DO - 10.1002/jrs.70011

M3 - Article

JO - Journal of Raman Spectroscopy

JF - Journal of Raman Spectroscopy

SN - 0377-0486

ER -