Influence of paleoenvironment on the carbon isotope compositions of pedogenic carbonate formed in Paleozoic vertic paleosols

Conference · Tue Dec 31 23:00:00 EST 1991 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5809242

Mora, C I; Driese, S G; Seager, P G ^[1]

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1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences

Pedogenic carbonate occurs in numerous vertic-featured paleosols developed in Paleozoic red bed successions of the southern and central Appalachians. The authors note systematic differences in the delta C-13 values of soil carbonate developed during pedogenesis in coastal-marine and distal alluvial plain environments as compared to pedogenesis in proximal alluvial plain environments. These differences have been measured in pedogenic carbonate occurring in late Silurian (Bloomsburg Fm.) vertic-featured paleosols. Evidence for pre-existing marine skeletal material in these paleosols has been observed only in the lowermost portions of the Bloomsburg Fm.; other paleosols were apparently devoid of any precursor carbonate phase. Therefore, the heavier isotopic signatures of pedogenic carbonate within coastal-marine and distal alluvial plain environments may be due to contributions from marine spray, marine or brackish groundwaters, or to less-extensive biological activity. Although carbonate nodules are commonly developed in all environments, rhizoliths appear to be more abundant in paleosols developed in proximal alluvial plain environments. Despite the large differences in carbon isotope compositions attributed to paleoenvironment, these vertic-featured paleosols share common patterns of carbonate cementation and isotopic trends (nodules enriched in C-13 relative to rhizoliths). Thus, despite the different pedogenic paleoenvironments, there were similar physico-chemical controls on soil carbonate precipitation. Better understanding of the paleoclimatic information retained in paleosols will require thorough petrographic, sedimentologic and geochemical studies.

• OSTI ID: 5809242
• Report Number(s): CONF-921058--
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 24:7; ISSN GAAPBC; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
APPALACHIAN BASIN
CARBON 13
CARBON ISOTOPES
CARBONATE ROCKS
CHEMISTRY
EVEN-ODD NUCLEI
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC STRUCTURES
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
NUCLEI
PALEOCLIMATOLOGY
PALEONTOLOGY
PALEOZOIC ERA
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SOIL CHEMISTRY
STABLE ISOTOPES