A chemical sequence of macromolecular organic matter in the CM chondrites
Citation
Naraoka, H., Mita, H., Komiya, M., Yoneda, S., Kojima, H., & Shimoyama, A. (2004). A chemical sequence of macromolecular organic matter in the CM chondrites. Meteoritics & Planetary Science, 39(3), 401-406.Publisher
The Meteoritical SocietyJournal
Meteoritics & Planetary ScienceAdditional Links
https://meteoritical.org/Abstract
A new organic parameter is proposed to show a chemical sequence of organic matter in carbonaceous chondrites, using carbon, hydrogen, and nitrogen concentrations of solvent-insoluble and high-molecular weight organic matter (macromolecules) and the molecular abundance of solvent-extractable organic compounds. The H/C atomic ratio of the macromolecule purified from nine CM chondrites including the Murchison, Sayama, and seven Antarctic meteorites varies widely from 0.11 to 0.72. During the H/C change of ~0.7 to ~0.3, the N/C atomic ratio remains at ~0.04, followed by a sharp decline from ~0.040 to ~0.017 between H/C ratios from ~0.3 to ~0.1. The H/CN/ degrees C sequence shows different degrees of organic matter thermal alteration among these chondrites in which the smaller H/C-N/C value implies higher alteration levels on the meteorite parent body. In addition, solvent-extractable organic compounds such as amino acids, carboxylic acids, and polycyclic aromatic hydrocarbons are abundant only in chondrites with macromolecular H/C values >~0.5. These organic compounds were extremely depleted in the chondrites with a macromolecular H/C value of <~0.5. Possibly, most solvent-extractable organic compounds could have been lost during the thermal alteration event that caused the H/C ratio of the macromolecule to fall below 0.4.Type
Articletext
Language
enISSN
1945-5100ae974a485f413a2113503eed53cd6c53
10.1111/j.1945-5100.2004.tb00101.x