Origin of insoluble organic matter in type 1 and 2 chondrites: New clues, new questions

摘要: Insoluble organic matter (IOM) extracted from primitive chondrites is a polyaromatic solid with structure and composition resembling that of terrestrial kerogens. A survey its has been carried out on series 27 CR, CM, CI ungrouped C2 carbonaceous (Tagish Lake, Bells, Essebi, Acfer 094) using infrared multi-wavelength Raman micro-spectroscopy (244, 514 785 nm laser excitations). The results show chondritic IOM PCA 91008 (CM2), WIS 91600 QUE 93005 Tagish Lake (C2 ungrouped) possibly Cold Bokkeveld (CM2) subjected to the past action short duration thermal metamorphism, presumably triggered by impacts. in most CM experienced moderate heavy aqueous alteration may have slightly modified collision-induced heating. However, even escaped significant metamorphism displays characteristics consistent formation processing, either protosolar disk or parent body. An alternative energetic process heating ion irradiation. After thoroughly analyzing both these scenarii, no conclusion can be drawn as which plausible mechanism nor whether took place prior after accretion. for first time width G band spectra collected excitation correlates O/C atomic ratio, suggesting major role oxygen cross-linking units. (c) 2014 Elsevier Ltd