Research output: Contribution to journal › Article › peer-review
SiO2 Inclusions in Sublithospheric Diamonds. / Zedgenizov, D. A.; Ragozin, A. L.; Kagi, H. et al.
In: Geochemistry International, Vol. 57, No. 9, 01.09.2019, p. 964-972.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - SiO2 Inclusions in Sublithospheric Diamonds
AU - Zedgenizov, D. A.
AU - Ragozin, A. L.
AU - Kagi, H.
AU - Yurimoto, H.
AU - Shatsky, V. S.
N1 - Publisher Copyright: © 2019, Pleiades Publishing, Ltd.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - Abstract: The paper describes mineralogical characteristics of SiO2 inclusions in sublithospheric diamonds, which typically have complicated growth histories showing alternating episodes of growth, dissolution, and postgrowth deformation and crushing processes. Nitrogen contents in all of the crystals do not exceed 71 ppm, and nitrogen is detected exclusively as B-defects. The carbon isotope composition of the diamonds varies from δ13С = –26.5 to –6.7‰. The SiO2 inclusions occur in association with omphacitic clinopyroxenes, majoritic garnets, CaSiO3, jeffbenite, and ferropericlase. All SiO2 inclusions are coesite, which is often associated with micro-blocks of kyanite in the same inclusions. It was suggested that these phases have been produced by the retrograde dissolution of primary Al-stishovite, which is also evidenced by the significant internal stresses in the inclusions and by deformations around them. The oxygen isotope composition of SiO2 inclusions in sublithospheric diamonds (δ18O up to 12.9‰) indicates a crustal origin of the protoliths. The negative correlation between the δ18O of the SiO2 inclusions and the δ13C of their host diamonds reflects interaction processes between slab-derived melts and reduced mantle rocks at depths greater than 270 km.
AB - Abstract: The paper describes mineralogical characteristics of SiO2 inclusions in sublithospheric diamonds, which typically have complicated growth histories showing alternating episodes of growth, dissolution, and postgrowth deformation and crushing processes. Nitrogen contents in all of the crystals do not exceed 71 ppm, and nitrogen is detected exclusively as B-defects. The carbon isotope composition of the diamonds varies from δ13С = –26.5 to –6.7‰. The SiO2 inclusions occur in association with omphacitic clinopyroxenes, majoritic garnets, CaSiO3, jeffbenite, and ferropericlase. All SiO2 inclusions are coesite, which is often associated with micro-blocks of kyanite in the same inclusions. It was suggested that these phases have been produced by the retrograde dissolution of primary Al-stishovite, which is also evidenced by the significant internal stresses in the inclusions and by deformations around them. The oxygen isotope composition of SiO2 inclusions in sublithospheric diamonds (δ18O up to 12.9‰) indicates a crustal origin of the protoliths. The negative correlation between the δ18O of the SiO2 inclusions and the δ13C of their host diamonds reflects interaction processes between slab-derived melts and reduced mantle rocks at depths greater than 270 km.
KW - carbon
KW - coesite
KW - diamonds
KW - inclusions
KW - oxygen
KW - stishovite
KW - subduction
KW - sublithospheric mantle
KW - MATO-GROSSO
KW - JUINA AREA
KW - ECLOGITIC DIAMONDS
KW - DEEP MANTLE
KW - SUBDUCTION
KW - LOWER-MANTLE
KW - MINERAL INCLUSIONS
KW - SUPERDEEP DIAMONDS
KW - ISOTOPE COMPOSITION
KW - OCEANIC-CRUST
UR - http://www.scopus.com/inward/record.url?scp=85071569728&partnerID=8YFLogxK
U2 - 10.1134/S0016702919090131
DO - 10.1134/S0016702919090131
M3 - Article
AN - SCOPUS:85071569728
VL - 57
SP - 964
EP - 972
JO - Geochemistry International
JF - Geochemistry International
SN - 0016-7029
IS - 9
ER -
ID: 21466594