Premium
Origins of meteoritic nanodiamonds investigated by coordinated atom‐probe tomography and transmission electron microscopy studies
Author(s) -
Lewis Josiah B.,
Floss Christine,
Isheim Dieter,
Daulton Tyrone L.,
Seidman David N.,
Ogliore Ryan
Publication year - 2020
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/maps.13373
Subject(s) - presolar grains , meteorite , allende meteorite , transmission electron microscopy , isotope , murchison meteorite , carbonaceous chondrite , asymptotic giant branch , chemistry , supernova , graphite , formation and evolution of the solar system , chondrite , analytical chemistry (journal) , astrophysics , materials science , astrobiology , physics , stars , nanotechnology , nuclear physics , organic chemistry , chromatography
To constrain the origins of meteoritic nanodiamonds, the abundance ratios of stable C isotopes in acid residues from the carbonaceous chondritic meteorite Allende CV 3 were measured using coordinated atom‐probe tomography ( APT ) and transmission electron microscopy ( TEM ). We combined our data with previously published APT data. A statistical analysis of this combined data set suggests an upper bound of 1 in 10 2 on the subpopulation that could have a large isotopic enrichment in 13 C relative to 12 C, consistent with the possible detection by secondary ion mass spectrometry of a similar enrichment in a 1 in 10 5 fraction, abundant enough to account for the Xe‐ HL anomalous isotopic component carried by the acid residues. Supernovae are believed to be the source of Xe‐ HL , leading to the mystery of why all other supernova minerals do not carry Xe‐ HL . The lack of Xe‐ HL in low‐density disordered supernova graphite suggests that the isotopically anomalous component is the nanodiamonds, but the disordered C in the residue is not ruled out. We discuss possible origins of the disordered C and implications of our results for proposed formation scenarios for nanodiamonds. At least 99% of the meteoritic acid residue exhibits no unambiguous evidence of presolar formation, although production with solar isotope ratios in asymptotic giant branch stars is not ruled out. Comparison of TEM and APT results indicates that a minority of the APT reconstructions may preferentially sample disordered C rather than nanodiamonds. If this is the case, a presolar origin for a larger fraction of the nanodiamonds remains possible.