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<p>The long-term global cooling of the Late Cretaceous was interrupted by an intense warming period at ~69 Ma known as the mid-Maastrichtian event. The underlying mechanisms of this climatic event and associated change in the global carbon cycle are, however, strongly debated, including a possible major reorganization of deep-ocean circulation patterns. How this reorganization co-varied with climate shifts and global carbon cycling is not known, mainly due to the lack of high-resolution studies. Here, we present new high-resolution stable isotope, Mg/Ca-derived bottom-water temperature, and CaCO<sub>3</sub> wt% records from IODP Site U1403 (North Atlantic) to reconstruct the climatic and oceanographic processes associated with the mid-Maastrichtian event. We observe a very dynamic and vigorous deep-ocean circulation that is characterized by precession-paced fluctuations that are proposed to reflect the interplay of different bottom-water source regions. Our results further point towards Large Igneous Province volcanism as a trigger not only for the mid-Maastrichtian event but also for the observed change in deep-water circulation. A clear shift towards the dominance of Northern Component Water bathing the North Atlantic at around 68 Ma signals the end of low-latitude waters in the North Atlantic, a bottom-water source that characterized the Cretaceous oceans for tens of millions of years.</p>

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Precession-paced late Maastrichtian bottom-water dynamics

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年3月27日

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  • Alexa Fischer,
  • Sietske J. Batenburg,
  • André Bahr,
  • Silke Voigt,
  • Anne Rheinberger,
  • Sarah Schmickal,
  • Silvia Rheinberger,
  • Markus Greule,
  • Stefan Rheinberger,
  • Oliver Friedrich

摘要

The long-term global cooling of the Late Cretaceous was interrupted by an intense warming period at ~69 Ma known as the mid-Maastrichtian event. The underlying mechanisms of this climatic event and associated change in the global carbon cycle are, however, strongly debated, including a possible major reorganization of deep-ocean circulation patterns. How this reorganization co-varied with climate shifts and global carbon cycling is not known, mainly due to the lack of high-resolution studies. Here, we present new high-resolution stable isotope, Mg/Ca-derived bottom-water temperature, and CaCO3 wt% records from IODP Site U1403 (North Atlantic) to reconstruct the climatic and oceanographic processes associated with the mid-Maastrichtian event. We observe a very dynamic and vigorous deep-ocean circulation that is characterized by precession-paced fluctuations that are proposed to reflect the interplay of different bottom-water source regions. Our results further point towards Large Igneous Province volcanism as a trigger not only for the mid-Maastrichtian event but also for the observed change in deep-water circulation. A clear shift towards the dominance of Northern Component Water bathing the North Atlantic at around 68 Ma signals the end of low-latitude waters in the North Atlantic, a bottom-water source that characterized the Cretaceous oceans for tens of millions of years.