Black shale deposition and faunal overturn in the Devonian Appalachian basin: Clastic starvation, seasonal water-column mixing, and efficient biolimiting nutrient recycling

Adam E. Murphy, Bradley B. Sageman, David J. Hollander, Timothy W. Lyons, Carlton E. Brett

Research output: Contribution to journalArticlepeer-review

219 Scopus citations

Abstract

Integrated geochemical data suggest that black shale deposition in the Devonian Geneseo Formation of western New York was initiated by the coincidence of siliciclastic starvation and the intensification of seasonal water column stratification and mixing. Once established, however, black shale deposition was maintained through efficient recycling of biolimiting nutrients which enhanced primary productivity. Recycling efficiency was achieved through a positive feedback loop of oscillating benthic redox conditions that enhanced N and P regeneration from sediments, sustained high primary productivity by returning nutrients to the photic zone during mixing, and ensured a downward flux of organic matter that drove or enhanced the episode development of benthic anoxia during stratification. This feedback was ultimately disrupted by rising siliciclastic influx, which diluted organic matter and restored benthic redox stability. The abrupt overturn of diverse, long-standing Appalachian basin marine communities may have been the result of trophic resource destabilization during Geneseo deposition.

Original languageEnglish (US)
Pages (from-to)280-291
Number of pages12
JournalPaleoceanography
Volume15
Issue number3
DOIs
StatePublished - Jun 1 2000

ASJC Scopus subject areas

  • Oceanography
  • Palaeontology

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