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Microbe-mediated preservation of invertebrate fecal pellets; evidence from the ichnofossil Phymatoderma burkei, Permian shallow-marine, Teresina Formation, southern Brazil

Kentaro Izumi, Renata Guimaraes Netto and Joao Henrique Dobler Lima
Microbe-mediated preservation of invertebrate fecal pellets; evidence from the ichnofossil Phymatoderma burkei, Permian shallow-marine, Teresina Formation, southern Brazil
Palaios (October 2015) 30 (10): 771-778

Abstract

Fecal pellet-filled trace fossil Phymatoderma burkei from the Permian shallow-marine Teresina Formation (southern Brazil) was microscopically and geochemically investigated to reveal the significance of physicochemical processes in the preservation of invertebrate fecal pellets. Scanning electron microscope (SEM) analysis shows micron-sized spherules only in the pelletal infill of P. burkei, but not within the surrounding host sandstone. These spherules show highly uniform morphology and size (approximately 1 mu m), and generally have hollow structures occasionally occurring as aggregates. Geochemically, such spherules are characterized by presence of Fe and Mn, occasionally with Ba. The evidence suggests that the spherules are mineral-replaced or mineral-encrusted microbial cells, which are most likely coccoid bacteria based on their morphological similarity. Within the fecal pellets excreted by the trace-maker of P. burkei, microbially mediated precipitation of Fe and Mn minerals probably occurred on or just near the outer surface of coccoid bacterial cells. Such microbial processes are important in the preservation of invertebrate fecal pellets excreted in shallow tiers, especially under wave- or current-influenced shallow-marine sedimentary conditions.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 30
Serial Issue: 10
Title: Microbe-mediated preservation of invertebrate fecal pellets; evidence from the ichnofossil Phymatoderma burkei, Permian shallow-marine, Teresina Formation, southern Brazil
Affiliation: National Institute for Environmental Studies, Center for Environmental Biology and Ecosystem Studies, Tsukuba, Japan
Pages: 771-778
Published: 201510
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
References: 57
Accession Number: 2016-003621
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch map
S30°40'00" - S30°40'00", W54°45'00" - W54°45'00"
Secondary Affiliation: Universidade do Vale do Rio dos Sinos, BRA, Brazil
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 201602
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