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Carbonate concretions: an ideal sedimentary host for microfossils

January 1, 1985

Microfossils extracted from carbonate concretions tend to be better preserved, more abundant and diverse, and more likely to retain delicate and fragile structures than those extracted from the surrounding rocks. Enhanced preservation correlates with early diagenetic concretion formation at or near the sediment-water interface and with higher carbonate, organic material, and metallic cation content than in surrounding rocks. Early diagenetic growth is inferred by diverging sedimentary laminations and small-scale sedimentary structures in fossiliferous carbonate concretions. High initial concentrations of microorganisms or fecal pellets may commonly be responsible for incipient carbonate-concretion growth. Excellent preservation is demonstrated by radiolarians and palynomorphs extracted from a carbonate concretion from the Middle Jurassic Shelikof Formation, southern Alaska.

Publication Year 1985
Title Carbonate concretions: an ideal sedimentary host for microfossils
DOI 10.1130/0091-7613(1985)13<212:CCAISH>2.0.CO;2
Authors C.D. Blome, N. R. Albert
Publication Type Article
Publication Subtype Journal Article
Series Title Geology
Index ID 70013014
Record Source USGS Publications Warehouse