Bibliographische Detailangaben
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Personen und Körperschaften:
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Galloway, J M (VerfasserIn); Vickers, M L (VerfasserIn); Price, G D (VerfasserIn); Poulton, T (VerfasserIn); Grasby, S E (VerfasserIn); Hadlari, T (VerfasserIn); Beauchamp, B (VerfasserIn); Sulphur, K (VerfasserIn) |
| Format: |
Elektronische Zeitschrift
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| Sprache: |
English
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| veröffentlicht: |
Cambridge University Press, 2019 |
| Gesamtaufnahme: |
GEM: Geo-mapping for Energy and Minerals
, Geological Magazine 2019., Natural Resources Canada, Contribution Series
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| Schlagwörter: |
Zeitschrift;
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| Quelle: |
GEOSCAN
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| Zusammenfassung: |
A new carbon isotope record for two high-latitude sedimentary successions t...
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 (delta-13Corg) of 4 per mille (V-PDB) and to a minimum of -30.7 per mille in the probable middle Volgian Stage. This is followed by a return to less negative values of c. -27 per mille. A smaller positive excursion in the Valanginian Stage of c. 2 per mille, reaching maximum values of -24.6 per mille, is related to the Weissert Event. The Volgian isotopic trends are consistent with other high-latitude records but do not appear in delta-13Ccarb records of Tethyan Tithonian strata. In the absence of any obvious definitive cause for the depleted delta-13Corg anomaly, we suggest several possible contributing factors. The Sverdrup Basin and other Arctic areas may have experienced compositional evolution away from open-marine delta-13C 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 delta-13Corg 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.
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