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A Raman spectroscopic study of organic matter in interplanetary dust particles and meteorites using multiple wavelength laser excitation
Author(s) -
Starkey N. A.,
Franchi I. A.,
Alexander C. M. O'D.
Publication year - 2013
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.12196
Subject(s) - chondrite , meteorite , raman spectroscopy , interplanetary dust cloud , analytical chemistry (journal) , carbonaceous chondrite , chemistry , mineralogy , astrophysics , physics , astrobiology , optics , solar system , chromatography
Raman spectroscopy was used to investigate insoluble organic matter ( IOM ) from a range of chondritic meteorites, and a suite of interplanetary dust particles ( IDP s). Three monochromatic excitation wavelengths (473 nm, 514 nm, 632 nm) were applied sequentially to assess variations in meteorite and IDP Raman peak parameters (carbon D and G bands) as a function of excitation wavelength (i.e., dispersion). Greatest dispersion occurs in CV s > OC s > CM s > CR s with type 3 chondrites compared at different excitation wavelengths displaying conformable relationships, in contrast to type 2 chondrites. These findings indicate homogeneity in the structural nature of type 3 chondrite IOM , while organic matter ( OM ) in type 2 chondrites appears to be inherently more heterogeneous. If type 2 and type 3 chondrite IOM shares a common source, then thermal metamorphism may have a homogenizing effect on the originally more heterogeneous OM . IDP Raman G bands fall on an extension of the trend displayed by chondrite IOM , with all IDP s having Raman parameters indicative of very disordered carbon, with almost no overlap with IOM . The dispersion effect displayed by IDP s is most similar to CM s for the G band, but intermediate between CM s and CR s for the D band. The existence of some overlapping Raman features in the IDP s and IOM indicates that their OM may share a common origin, but the IDP s preserve more pristine OM that may have been further disordered by ion irradiation. H, C, and N isotopic data for the IDP s reveal that the disordered carbon in IDP s corresponds with higher δ 15 N and lower δ 13 C.