title: Decoupling biogeochemical records, extinction, and environmental change during the Cambrian SPICE event.
abstract: Several positive carbon isotope excursions in Lower Paleozoic rocks, including the prominent Upper Cambrian Steptoean Positive Carbon Isotope Excursion (SPICE), are thought to reflect intermittent perturbations in the hydrosphere-biosphere system. Models explaining these secular changes are abundant, but the synchronicity and regional variation of the isotope signals are not well understood. Examination of cores across a paleodepth gradient in the Upper Cambrian central Missouri intrashelf basin (United States) reveals a time-transgressive, facies-dependent nature of the SPICE. Although the SPICE event may be a global signal, the manner in which it is recorded in rocks should and does vary as a function of facies and carbonate platform geometry. We call for a paradigm shift to better constrain facies, stratigraphic, and biostratigraphic architecture and to apply these observations to the variability in magnitude, stratigraphic extent, and timing of the SPICE signal, as well as other biogeochemical perturbations, to elucidate the complex processes driving the ocean-carbonate system.
authors.affiliation: Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Schiffbauer
authors.affiliation: Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: John Warren
authors.initials: JW
authors.lastname: Huntley
authors.affiliation: Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Fike
authors.affiliation: Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Matthew Jarrell
authors.initials: MJ
authors.lastname: Jeffrey
authors.affiliation: Boone Pickens School of Geology, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Jay M
authors.initials: JM
authors.lastname: Gregg
authors.affiliation: Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Shelton
keywords: Cambrian; Missouri; Sauk III transgression; Steptoean Positive Carbon Isotope Excursion; extinction; facies dependence; time transgressive