High-frequency fluctuations in redox conditions during the latest Permian mass extinction

C. Mettam, A. L. Zerkle, M. W. Claire, G. Izon, C. J. Junium, R. J. Twitchett

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

New high-resolution geochemical and sedimentological data from Fiskegrav, East Greenland, reveal fluctuations in marine redox conditions associated with the final disappearance of bioturbating organisms during the latest Permian mass extinction (LPME). Sedimentological observations imply a transgressive episode, and associated geochemical evidence for decreasing oxygen availability and the establishment of persistently ferruginous (Fe2 +-rich) conditions implies the shoreward migration of oxygen deficient waters. The long-term decline in dissolved oxygen (DO) availability could have been exacerbated by increasing water temperatures, reducing the solubility of oxygen and promoting thermal stratification. Mixing of the water column could have been further inhibited by freshwater influxes that could have generated salinity contrasts that reinforced thermal stratification. Enhanced runoff could also have increased the delivery of nutrients to the marine shelf, stimulating biological oxygen demand (BOD). During the transition to persistently ferruginous conditions we identify intervals of intermittent benthic meiofaunal recolonization, events that we attribute to small transient increases in DO availability. The mechanism controlling these fluctuations remains speculative, but given the possible centennial- to millennial-scale frequency of these changes, we hypothesise that the mid-latitude setting of Fiskegrav during the Late Permian was sensitive to changes in atmospheric circulation patterns, which may have influenced local precipitation and intermittently modulated some of the processes promoting anoxia.

Original languageEnglish (US)
Pages (from-to)210-223
Number of pages14
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume485
DOIs
StatePublished - Nov 1 2017

Keywords

  • East Greenland
  • Fe speciation
  • Ferruginous sea
  • Palaeoenvironment
  • Stable isotopes

ASJC Scopus subject areas

  • Oceanography
  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes
  • Palaeontology

Fingerprint Dive into the research topics of 'High-frequency fluctuations in redox conditions during the latest Permian mass extinction'. Together they form a unique fingerprint.

Cite this