Parallel trends in organic and inorganic carbon isotopes across the Permian/Triassic boundary

Journal Article · Tue Dec 01 00:00:00 EST 1992 · American Journal of Science; (United States)

DOI:https://doi.org/10.2475/ajs.292.10.727· OSTI ID:6918070

Magaritz, M ^[1]; Krishnamurthy, R V ^[2]; Holser, W T ^[3]

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1. Weizmann Inst., Rehovot (Israel)
2. California Inst. of Technology, Pasadena (United States)
3. Univ. of Oregon, Eugene (United States) Cornell Univ., Ithaca, NY (United States)

Stable carbon isotope ratios in both inorganic and organic reservoirs have been widely applied to model environmental and sedimentological changes on a global scale. Most studies dealing with major extinction events have used the record of inorganic carbon. In this paper the authors report the relation between shifts in carbon-13 content of organic matter and coexisting carbonate fractions at a major extinction event, the Permian/Triassic boundary. They found that both [delta][sup 13]C[sub carb] and [delta][sup 13]C[sub org] of the surface ocean varied dramatically across the boundary, but the fractionation [Delta][sup 13]C between organic matter and carbonate remained constant. This result appreciably restricts the interpretation of changes in the carbon cycle during this critical interval. The new data are best explained by a combination of two mechanisms for variation in [delta][sup 13]C[sub carb]: (1) burial and erosion of organic carbon, with a long time constant; and (2) sequestration of organic carbon into shallow and deep oceanic reservoirs, with a shorter time constant. For application to their case, the first mechanism is limited by possible buildup of marine pCO[sub 2], which would increase the isotopic fractionation factor. The second mechanism is limited in application to short-term transient variations in [delta][sup 13]C. Modeling of the carbon cycle and its variations of [delta][sup 13]C must take both mechanisms into account.

• OSTI ID: 6918070
• Journal Information: American Journal of Science; (United States), Vol. 292:10; ISSN 0002-9599
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
CARBON 13
ISOTOPE RATIO
CARBONATES
SEDIMENTS
ISOTOPE DATING
CARBON CYCLE
CLIMATE MODELS
CLIMATIC CHANGE
EROSION
ORGANIC COMPOUNDS
PALEOCLIMATOLOGY
PERMIAN PERIOD
SEDIMENTATION
TRIASSIC PERIOD
AGE ESTIMATION
CARBON COMPOUNDS
CARBON ISOTOPES
EVEN-ODD NUCLEI
GEOLOGIC AGES
ISOTOPES
LIGHT NUCLEI
MATHEMATICAL MODELS
MESOZOIC ERA
NUCLEI
OXYGEN COMPOUNDS
PALEONTOLOGY
PALEOZOIC ERA
STABLE ISOTOPES
540210* - Environment
Terrestrial- Basic Studies- (1990-)
580000 - Geosciences