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Carbon isotope fractionation between graphite and diamond during shock experiments
Author(s) -
Maruoka Teruyuki,
Koeberl Christian,
Matsuda Junichi,
Syono Yasuhiko
Publication year - 2003
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2003.tb00311.x
Subject(s) - diamond , graphite , carbon fibers , fractionation , impurity , shock (circulatory) , mass independent fractionation , diamond type , materials science , isotope fractionation , analytical chemistry (journal) , mineralogy , material properties of diamond , geology , chemistry , environmental chemistry , composite material , chromatography , medicine , organic chemistry , composite number
— Carbon isotopic compositions were measured for shock‐produced diamond and shocked graphite formed at peak pressures ranging from 37 to 52 GPa. The δ 13 C values of diamonds produced in a sealed container were generally lower than that of the initial graphite. The differences in the carbon isotopic composition between initial graphite and shocked graphite/diamond may reflect kinetic isotopic fractionation during the oxidation of the graphite/diamond and/or analytical artifacts possibly induced by impurities in the samples. The pressure effect on the isotopic fractionations between graphite and diamond can be estimated from the δ 13 C values of impurity‐free diamonds produced using a vented container from which gases, including oxygen, in pore spaces escaped during or after the diamond formation (e.g., 0.039 ± 0.085‰ at a peak pressure of 52 GPa). Any isotopic fractionation induced by shock conversion of graphite to diamond is too small to be detected in natural shock‐induced diamond‐graphite systems related to terrestrial impact cratering processes.