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dc.contributor.authorMatheson, Edward
dc.contributor.authorFrank, Tracy D.
dc.date.accessioned2020-04-30T18:29:54Z
dc.date.available2020-04-30T18:29:54Z
dc.date.issued2020-03-11
dc.identifier.citationMatheson, E.J. and Frank, T.D. (2020), Phosphorites, glass ramps and carbonate factories: The evolution of an epicontinental sea and a Late Palaeozoic upwelling system (Phosphoria Rock Complex). Sedimentology. doi:10.1111/sed.12731en
dc.identifier.urihttp://hdl.handle.net/1974/27754
dc.descriptionThis is the peer reviewed version of the following article: Matheson, E.J. and Frank, T.D. (2020), Phosphorites, glass ramps and carbonate factories: The evolution of an epicontinental sea and a Late Palaeozoic upwelling system (Phosphoria Rock Complex). Sedimentology. doi:10.1111/sed.12731, which has been published in final form at https://doi.org/10.1111/sed.12731. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.en
dc.description.abstractThe Permian Phosphoria Rock Complex of the western USA contains an enigmatic assemblage of bioelemental rocks (i.e. phosphorites and cherts) that accumulated in a depositional system with no modern analogue. This study utilizes detailed sedimentological, stratigraphic and petrographic examination to evaluate the genetic relations of phosphorites, spiculitic chert and carbonates of the Ervay cycle (depositional sequence) and propose a unified oceanographic model for their deposition. The Ervay cycle contains three marine and one terrestrial facies association, each of which composes the bulk of a single lithostratigraphic unit. The marine facies associations include: (i) granular phosphorites (Retort Member); (ii) spiculitic cherty dolostones (Tosi Member); and (iii) marine to peritidal carbonates (Ervay Member). Red beds and intercalated gypsum (Goose Egg Formation) accumulated in the vast desert adjacent to the sea. The three marine members are chronostratigraphically distinct, successive and conformably stacked. They are not coeval facies belts. They reflect the progressive evolution of the epicontinental sea from the location of: (i) authigenic phosphogenesis (lowstand to transgression); to (ii) a glass ramp with biosiliceous (sponge) deposition (transgression); to (iii) a carbonate ramp (regression). This succession of switching biochemical sediment factories records the evolution of sea‐level, nutrient supply, upwelling, oxygenation and dissolved Si. Intense upwelling, potentially coupled with aeolian input, led to sedimentary condensation and phosphogenesis. Decreased upwelling intensity during transgression increased oxygenation sufficiently for a siliceous sponge benthos. Sponges were favoured over biocalcifiers due to elevated dissolved silica and a low carbonate saturation state. The cessation of sponge dominance and transition to a carbonate ramp occurred due to decreasing upwelling intensity, Si drawdown and an increased carbonate saturation state. These results provide insight into the role of Si loading in faunal turnover on glass ramps and highlight how differences in dissolved Si utilizers in pre‐Cretaceous versus post‐Cretaceous upwelling systems influence the resultant deposits.en
dc.language.isoenen
dc.publisherWileyen
dc.subjectErvay Memberen
dc.subjectGlass Rampen
dc.subjectPalaeoceanographyen
dc.subjectPermianen
dc.subjectPhosphoriaen
dc.subjectPhosphoritesen
dc.subjectSilica Cycleen
dc.subjectUpwellingen
dc.titlePhosphorites, Glass Ramps and Carbonate Factories: The Evolution of an Epicontinental Sea and a Late Palaeozoic Upwelling System (Phosphoria Rock Complex)en
dc.typejournal articleen
dc.identifier.doihttps://doi.org/10.1111/sed.12731


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