Latitude-dependant climate changes across the Aptian Oceanic Anoxic Event 1a

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt


  • Fulltext

    Forlagets udgivne version, 6,15 MB, PDF-dokument

The understanding of the climatic evolution during the Early Cretaceous in general, and across Oceanic Anoxic Event 1a (OAE-1a) in particular, has generally been derived from Tethyan localities, implying large uncertainties about their significance at a global scale. In this study, high-resolution clay-mineral assemblage analyses have been performed on the Hauterivian to lower Aptian cored section of the North Jens-1 well, located in the Danish Central Graben, North Sea, in the Boreal Realm. Large amounts of detrital kaolinite are observed throughout the core, indicating the presence of a local, kaolinite-rich source. A long-term decline in kaolinite content is recorded from the upper Hauterivian to the lowermost pre-OAE-1a Aptian, followed by a sharp rise within the OAE-1a interval. This trend is similar to that observed in the Tethyan Realm, where a supra-regional climatic evolution is observed, including: (i) relatively humid conditions in the late Hauterivian; (ii) a shift towards overall drier conditions in the latest Barremian – earliest Aptian; and (iii) renewed humid conditions during the unfolding of OAE-1a. However, the precise timing of climate change across OAE-1a differs between the Tethyan and Boreal Realms. The shift towards humid conditions coincides with the onset of OAE-1a (segment C3) in the Tethyan Realm, followed by a return to drier conditions in the second half of the event. In the Boreal Realm, however, the onset of OAE-1a was characterised by a relatively dry climate, followed by an increase in humidity within its middle part (segments C4–C5) that persisted through the remainder of the early Aptian. Consequently, there was a non-linear change in precipitation patterns across latitudinal belts during the unfolding of OAE-1a. Similar conclusions have been drawn for other OAEs, suggesting a more complex weathering feedback mechanism during hyperthermal events than generally assumed.

TidsskriftPalaeogeography, Palaeoclimatology, Palaeoecology
Antal sider16
StatusUdgivet - 2022

Bibliografisk note

Funding Information:
We gratefully acknowledge the Danish Offshore Technology Centre (DTU offshore) under the TRD Lower Cretaceous (LOCRETA) programme for funding the research, as well as the Danish Underground Consortium (TotalEnergies E&P Denmark, Noreco & Nordsøfonden) for providing data and granting permission to publish this work. We thank Alexis Godet and an anonymous reviewer for their valuable and critical reviews.

Publisher Copyright:
© 2022 The Authors

Antal downloads er baseret på statistik fra Google Scholar og

Ingen data tilgængelig

ID: 316820123