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Finding the VOICE: Organic carbon isotope chemostratigraphy of Late Jurassic - Early Cretaceous Arctic Canada

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  • Jennifer M. Galloway, Natural Resources Canada
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  • Madeleine L. Vickers, University of Copenhagen
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  • Gregory D. Price, University of Plymouth
  • ,
  • Terence Poulton, Natural Resources Canada
  • ,
  • Stephen E. Grasby, Natural Resources Canada
  • ,
  • Thomas Hadlari, Natural Resources Canada
  • ,
  • Benoit Beauchamp, University of Calgary
  • ,
  • Kyle Sulphur, Natural Resources Canada, University of Calgary

A new carbon isotope record for two high-latitude sedimentary successions that span the Jurassic-Cretaceous boundary interval in the Sverdrup Basin of Arctic Canada is presented. This study, combined with other published Arctic data, shows a large negative isotopic excursion of organic carbon (δ Corg) of 4‰ (V-PDB) and to a minimum of -30.7‰ in the probable middle Volgian Stage. This is followed by a return to less negative values of c. -27‰. A smaller positive excursion in the Valanginian Stage of c. 2‰, reaching maximum values of -24.6‰, is related to the Weissert Event. The Volgian isotopic trends are consistent with other high-latitude records but do not appear in δ Ccarb records of Tethyan Tithonian strata. In the absence of any obvious definitive cause for the depleted δ Corg anomaly, we suggest several possible contributing factors. The Sverdrup Basin and other Arctic areas may have experienced compositional evolution away from open-marine δ C values during the Volgian Age due to low global or large-scale regional sea levels, and later become effectively coupled to global oceans by Valanginian time when sea level rose. A geologically sudden increase in volcanism may have caused the large negative δ Corg values seen in the Arctic Volgian records but the lack of precise geochronological age control for the Jurassic-Cretaceous boundary precludes direct comparison with potentially coincident events, such as the Shatsky Rise. This study offers improved correlation constraints and a refined C-isotope curve for the Boreal region throughout latest Jurassic and earliest Cretaceous time.

Original languageEnglish
JournalGeological Magazine
Issue10, special issue
Pages (from-to)1643-1657
Number of pages15
Publication statusPublished - Oct 2020

    Research areas

  • Arctic, Canada, carbon isotopes, Jurassic-Cretaceous

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