Carbon isotopic compositions of Antarctic carbonaceous chondrites with relevance to the alteration and existence of organic matter

Hiroshi Naraoka, Akira Shimoyama, Osamu Matsubaya, Kaoru Harada

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Bulk carbon isotopic compositions of 26 Antarctic carbonaceous chondrites (33 specimens) are reported and discussed with relevance to the processes involved in their alteration and the existence of solvent-extractable organic matter. The δ13C values (relative to PDB) vary from -16.6 to +0.9‰. The average value (-6.2‰) is higher than that for non-Antarctic carbonaceous chondrites by -6‰. The difference may be explained by contamination of terrestrial organic carbon on non-Antarctic chondrites and/or different populations of parent bodies. Most Antarctic carbonaceous chondrites have an apparent trend ("a major sequence") that the δ13C value becomes higher with increasing carbon content. The trend is likely to be explained by a mixing model of two components; isotopically heavy and labile component (solvent-extractable organic matter and carbonate), and isotopically light and inert acid-insoluble component (kerogen-like matter). In addition, an unique group (altered specimens) is characterized by relatively high content and isotopically light carbon. For seven CM chondrites, δ13C values of residues after the hot H2O and HCl/HF treatment are also reported. Despite considerable isotopic variations of bulk carbon, the δ13C values of acid-insoluble residues may be classified into two groups: isotopically light (-15 to -13‰) and heavy (-9 to -7‰) ones. Most kerogen-like matters belong to the light group, which are isotopically similar to non-Antarctic kerogen-like matter. The altered specimens have isotopically light bulk carbon (-15‰), which is similar to those of their kerogen-like matter; they probably lost heavy components such as solvent-extractable organic matters (e.g., amino acid and carboxylic acid) and carbonates during aqueous alteration and thermal metamorphism on parent bodies. This is in accord with mineralogical and oxygen isotope studies. The presence of solvent-extractable organic matter is one of the important factors controlling bulk carbon isotopes in carbonaceous chondrites.

Original languageEnglish
Pages (from-to)155-168
Number of pages14
JournalGEOCHEMICAL JOURNAL
Volume31
Issue number3
DOIs
Publication statusPublished - Jan 1 1997

Fingerprint

carbonaceous chondrites
carbonaceous chondrite
Kerogen
Biological materials
kerogen
isotopic composition
Carbon
organic matter
carbon
Chemical analysis
Carbonates
parent body
chondrite
Oxygen Isotopes
chondrites
Carbon Isotopes
carbonate
Acids
acids
acid

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Cite this

Carbon isotopic compositions of Antarctic carbonaceous chondrites with relevance to the alteration and existence of organic matter. / Naraoka, Hiroshi; Shimoyama, Akira; Matsubaya, Osamu; Harada, Kaoru.

In: GEOCHEMICAL JOURNAL, Vol. 31, No. 3, 01.01.1997, p. 155-168.

Research output: Contribution to journalArticle

@article{7488202369cc4028ab8f3ade7ea0bc66,
title = "Carbon isotopic compositions of Antarctic carbonaceous chondrites with relevance to the alteration and existence of organic matter",
abstract = "Bulk carbon isotopic compositions of 26 Antarctic carbonaceous chondrites (33 specimens) are reported and discussed with relevance to the processes involved in their alteration and the existence of solvent-extractable organic matter. The δ13C values (relative to PDB) vary from -16.6 to +0.9‰. The average value (-6.2‰) is higher than that for non-Antarctic carbonaceous chondrites by -6‰. The difference may be explained by contamination of terrestrial organic carbon on non-Antarctic chondrites and/or different populations of parent bodies. Most Antarctic carbonaceous chondrites have an apparent trend ({"}a major sequence{"}) that the δ13C value becomes higher with increasing carbon content. The trend is likely to be explained by a mixing model of two components; isotopically heavy and labile component (solvent-extractable organic matter and carbonate), and isotopically light and inert acid-insoluble component (kerogen-like matter). In addition, an unique group (altered specimens) is characterized by relatively high content and isotopically light carbon. For seven CM chondrites, δ13C values of residues after the hot H2O and HCl/HF treatment are also reported. Despite considerable isotopic variations of bulk carbon, the δ13C values of acid-insoluble residues may be classified into two groups: isotopically light (-15 to -13‰) and heavy (-9 to -7‰) ones. Most kerogen-like matters belong to the light group, which are isotopically similar to non-Antarctic kerogen-like matter. The altered specimens have isotopically light bulk carbon (-15‰), which is similar to those of their kerogen-like matter; they probably lost heavy components such as solvent-extractable organic matters (e.g., amino acid and carboxylic acid) and carbonates during aqueous alteration and thermal metamorphism on parent bodies. This is in accord with mineralogical and oxygen isotope studies. The presence of solvent-extractable organic matter is one of the important factors controlling bulk carbon isotopes in carbonaceous chondrites.",
author = "Hiroshi Naraoka and Akira Shimoyama and Osamu Matsubaya and Kaoru Harada",
year = "1997",
month = "1",
day = "1",
doi = "10.2343/geochemj.31.155",
language = "English",
volume = "31",
pages = "155--168",
journal = "Geochemical Journal",
issn = "0016-7002",
publisher = "The Physiological Society of Japan",
number = "3",

}

TY - JOUR

T1 - Carbon isotopic compositions of Antarctic carbonaceous chondrites with relevance to the alteration and existence of organic matter

AU - Naraoka, Hiroshi

AU - Shimoyama, Akira

AU - Matsubaya, Osamu

AU - Harada, Kaoru

PY - 1997/1/1

Y1 - 1997/1/1

N2 - Bulk carbon isotopic compositions of 26 Antarctic carbonaceous chondrites (33 specimens) are reported and discussed with relevance to the processes involved in their alteration and the existence of solvent-extractable organic matter. The δ13C values (relative to PDB) vary from -16.6 to +0.9‰. The average value (-6.2‰) is higher than that for non-Antarctic carbonaceous chondrites by -6‰. The difference may be explained by contamination of terrestrial organic carbon on non-Antarctic chondrites and/or different populations of parent bodies. Most Antarctic carbonaceous chondrites have an apparent trend ("a major sequence") that the δ13C value becomes higher with increasing carbon content. The trend is likely to be explained by a mixing model of two components; isotopically heavy and labile component (solvent-extractable organic matter and carbonate), and isotopically light and inert acid-insoluble component (kerogen-like matter). In addition, an unique group (altered specimens) is characterized by relatively high content and isotopically light carbon. For seven CM chondrites, δ13C values of residues after the hot H2O and HCl/HF treatment are also reported. Despite considerable isotopic variations of bulk carbon, the δ13C values of acid-insoluble residues may be classified into two groups: isotopically light (-15 to -13‰) and heavy (-9 to -7‰) ones. Most kerogen-like matters belong to the light group, which are isotopically similar to non-Antarctic kerogen-like matter. The altered specimens have isotopically light bulk carbon (-15‰), which is similar to those of their kerogen-like matter; they probably lost heavy components such as solvent-extractable organic matters (e.g., amino acid and carboxylic acid) and carbonates during aqueous alteration and thermal metamorphism on parent bodies. This is in accord with mineralogical and oxygen isotope studies. The presence of solvent-extractable organic matter is one of the important factors controlling bulk carbon isotopes in carbonaceous chondrites.

AB - Bulk carbon isotopic compositions of 26 Antarctic carbonaceous chondrites (33 specimens) are reported and discussed with relevance to the processes involved in their alteration and the existence of solvent-extractable organic matter. The δ13C values (relative to PDB) vary from -16.6 to +0.9‰. The average value (-6.2‰) is higher than that for non-Antarctic carbonaceous chondrites by -6‰. The difference may be explained by contamination of terrestrial organic carbon on non-Antarctic chondrites and/or different populations of parent bodies. Most Antarctic carbonaceous chondrites have an apparent trend ("a major sequence") that the δ13C value becomes higher with increasing carbon content. The trend is likely to be explained by a mixing model of two components; isotopically heavy and labile component (solvent-extractable organic matter and carbonate), and isotopically light and inert acid-insoluble component (kerogen-like matter). In addition, an unique group (altered specimens) is characterized by relatively high content and isotopically light carbon. For seven CM chondrites, δ13C values of residues after the hot H2O and HCl/HF treatment are also reported. Despite considerable isotopic variations of bulk carbon, the δ13C values of acid-insoluble residues may be classified into two groups: isotopically light (-15 to -13‰) and heavy (-9 to -7‰) ones. Most kerogen-like matters belong to the light group, which are isotopically similar to non-Antarctic kerogen-like matter. The altered specimens have isotopically light bulk carbon (-15‰), which is similar to those of their kerogen-like matter; they probably lost heavy components such as solvent-extractable organic matters (e.g., amino acid and carboxylic acid) and carbonates during aqueous alteration and thermal metamorphism on parent bodies. This is in accord with mineralogical and oxygen isotope studies. The presence of solvent-extractable organic matter is one of the important factors controlling bulk carbon isotopes in carbonaceous chondrites.

UR - http://www.scopus.com/inward/record.url?scp=0030814531&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030814531&partnerID=8YFLogxK

U2 - 10.2343/geochemj.31.155

DO - 10.2343/geochemj.31.155

M3 - Article

AN - SCOPUS:0030814531

VL - 31

SP - 155

EP - 168

JO - Geochemical Journal

JF - Geochemical Journal

SN - 0016-7002

IS - 3

ER -