Research output: Contribution to journal › Article › peer-review
Diamond-inclusion system recording old deep lithosphere conditions at Udachnaya (Siberia). / Nestola, Fabrizio; Zaffiro, Gabriele; Mazzucchelli, Mattia L. et al.
In: Scientific Reports, Vol. 9, No. 1, 12586, 29.08.2019, p. 12586.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Diamond-inclusion system recording old deep lithosphere conditions at Udachnaya (Siberia)
AU - Nestola, Fabrizio
AU - Zaffiro, Gabriele
AU - Mazzucchelli, Mattia L.
AU - Nimis, Paolo
AU - Andreozzi, Giovanni B.
AU - Periotto, Benedetta
AU - Princivalle, Francesco
AU - Lenaz, Davide
AU - Secco, Luciano
AU - Pasqualetto, Leonardo
AU - Logvinova, Alla M.
AU - Sobolev, Nikolay V.
AU - Lorenzetti, Alessandra
AU - Harris, Jeffrey W.
PY - 2019/8/29
Y1 - 2019/8/29
N2 - Diamonds and their inclusions are unique fragments of deep Earth, which provide rare samples from inaccessible portions of our planet. Inclusion-free diamonds cannot provide information on depth of formation, which could be crucial to understand how the carbon cycle operated in the past. Inclusions in diamonds, which remain uncorrupted over geological times, may instead provide direct records of deep Earth’s evolution. Here, we applied elastic geothermobarometry to a diamond-magnesiochromite (mchr) host-inclusion pair from the Udachnaya kimberlite (Siberia, Russia), one of the most important sources of natural diamonds. By combining X-ray diffraction and Fourier-transform infrared spectroscopy data with a new elastic model, we obtained entrapment conditions, Ptrap = 6.5(2) GPa and Ttrap = 1125(32)–1140(33) °C, for the mchr inclusion. These conditions fall on a ca. 35 mW/m2 geotherm and are colder than the great majority of mantle xenoliths from similar depth in the same kimberlite. Our results indicate that cold cratonic conditions persisted for billions of years to at least 200 km in the local lithosphere. The composition of the mchr also indicates that at this depth the lithosphere was, at least locally, ultra-depleted at the time of diamond formation, as opposed to the melt-metasomatized, enriched composition of most xenoliths.
AB - Diamonds and their inclusions are unique fragments of deep Earth, which provide rare samples from inaccessible portions of our planet. Inclusion-free diamonds cannot provide information on depth of formation, which could be crucial to understand how the carbon cycle operated in the past. Inclusions in diamonds, which remain uncorrupted over geological times, may instead provide direct records of deep Earth’s evolution. Here, we applied elastic geothermobarometry to a diamond-magnesiochromite (mchr) host-inclusion pair from the Udachnaya kimberlite (Siberia, Russia), one of the most important sources of natural diamonds. By combining X-ray diffraction and Fourier-transform infrared spectroscopy data with a new elastic model, we obtained entrapment conditions, Ptrap = 6.5(2) GPa and Ttrap = 1125(32)–1140(33) °C, for the mchr inclusion. These conditions fall on a ca. 35 mW/m2 geotherm and are colder than the great majority of mantle xenoliths from similar depth in the same kimberlite. Our results indicate that cold cratonic conditions persisted for billions of years to at least 200 km in the local lithosphere. The composition of the mchr also indicates that at this depth the lithosphere was, at least locally, ultra-depleted at the time of diamond formation, as opposed to the melt-metasomatized, enriched composition of most xenoliths.
KW - EQUATION-OF-STATE
KW - INFRARED-ABSORPTION
KW - THERMAL-EXPANSION
KW - SOLID INCLUSIONS
KW - HIGH-PRESSURES
KW - SPINEL
KW - GARNET
KW - TEMPERATURE
KW - BEHAVIOR
KW - MAGNESIOCHROMITE
UR - http://www.scopus.com/inward/record.url?scp=85071643963&partnerID=8YFLogxK
U2 - 10.1038/s41598-019-48778-x
DO - 10.1038/s41598-019-48778-x
M3 - Article
C2 - 31467318
AN - SCOPUS:85071643963
VL - 9
SP - 12586
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
IS - 1
M1 - 12586
ER -
ID: 21465377