Show simple item record

dc.contributor.authorRuhl, Micha
dc.date.accessioned2021-11-22T15:09:30Z
dc.date.available2021-11-22T15:09:30Z
dc.date.issued2021
dc.date.submitted2021en
dc.identifier.citationAlexander J. Dickson, Hugh C. Jenkyns, Erdem Idiz, Tim C. Sweere, Melissa J. Murphy, Sander H. J. M. van den Boorn, Micha Ruhl, James S. Eldrett, Donald Porcelli, New Constraints on Global Geochemical Cycling During Oceanic Anoxic Event 2 (Late Cretaceous) From a 6-Million-year Long Molybdenum-Isotope Record, Geochemistry, Geophysics, Geosystems, 2021, 22, e2020GC009246en
dc.identifier.otherY
dc.identifier.urihttp://hdl.handle.net/2262/97583
dc.description.abstractIntervals of extreme warmth are predicted to drive a decrease in the oxygen content of the oceans. This prediction has been tested for the acme of short (<1 million years) episodes of significant marine anoxia in the Phanerozoic geological record known as Oceanic Anoxic Events (OAEs). However, there is a paucity of data spanning prolonged multi-million-year intervals of geological time before and after OAEs. We present a Mo-isotope record from limestones and marlstones of the Eagle Ford Group, South Texas, which was deposited in the southern Cretaceous Western Interior Seaway of North America during a 6-million-year period encompassing Oceanic Anoxic Event 2 (Late Cenomanian–early Turonian: ~94 Ma). Mo-isotope compositions from deposits that formed in euxinic (sulfidic) conditions before OAE 2 allow the paleo-seawater composition to be constrained to 1.1–1.9 ‰. This range of values overlaps previous estimates of up to ~1.5 ‰ for the peak of OAE 2 determined from similarly sulfidic sediments deposited in the restricted proto-North Atlantic Ocean. Mo-isotopes thus varied by less than a few tenths of per mil across one of the most extreme intervals of global deoxygenation in the Late Phanerozoic. Rather than a limited change in oceanic deoxygenation, we suggest that the new data reflect changes to global iron cycling linked to basalt-seawater interaction, terrestrial weathering and expanded partially oxygenated shallow shelf-seas that played a key role in the burial of isotopically light molybdenum, thus acting as a counterbalance to its removal into sulfidic sediments.en
dc.language.isoenen
dc.relation.ispartofseriesGeochemistry, Geophysics, Geosystems,;
dc.relation.ispartofseries22;
dc.relation.ispartofseriese2020GC009246;
dc.rightsYen
dc.titleNew Constraints on Global Geochemical Cycling During Oceanic Anoxic Event 2 (Late Cretaceous) From a 6-Million-year Long Molybdenum-Isotope Recorden
dc.typeJournal Articleen
dc.type.supercollectionscholarly_publicationsen
dc.type.supercollectionrefereed_publicationsen
dc.identifier.peoplefinderurlhttp://people.tcd.ie/ruhlm
dc.identifier.rssinternalid235060
dc.identifier.doihttps://doi. org/10.1029/2020GC009246
dc.rights.ecaccessrightsopenAccess
dc.relation.doihttps://doi. org/10.1029/2020GC009246en
dc.relation.citesCitesen
dc.identifier.orcid_id0000-0001-8170-0399
dc.status.accessibleNen
dc.rights.restrictedAccessY
dc.date.restrictedAccessEndDate2023-11-01


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record