EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Cadmium as a tracer of volcanism at the Cretaceous-Paleogene boundary

Steffanie Sillitoe-Kukas1, Munir Humayun1, Thierry Adatte2, and Gerta Keller3
Steffanie Sillitoe-Kukas et al.
  • 1National High Magnetic Field Laboratory and Department of Earth, Ocean & Atmospheric Science, Florida State University, Tallahassee, FL 32310-3706, USA
  • 2Institute of Earth Sciences (ISTE), University of Lausanne, Géopolis, CH-1015 Lausanne, Switzerland
  • 3Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, USA

Major volcanic eruptions like the Deccan have long been invoked as causes of global mass extinctions. Deccan volcanism erupted ~ 600,000 km3 over the span of ~ 700 ka contemporaneously with the end-Cretaceous mass extinction. It has been difficult to establish a correlation between eruption size and extinction intensity because the frequency of eruptions and extent of degassing of individual flows is not well constrained. For example, the eruption of the same amount of lava by high frequency, low effusion flows is less likely to result in a mass extinction than by eruption of low frequency, high effusion flows. This is due to volcanic eruptions outgassing climate perturbing gases SO2 and CO2. When in the atmosphere, SO2 and CO2 could lead to a global climatic catastrophe capable of driving the extinction observed in planktic foraminifera that preceded the end-Cretaceous mass extinction by 200 ka. To determine the role Deccan volcanism played on the extinction it is critical to constrain the eruptive and effusive rates of Deccan eruptions. In addition to SO2 and CO2, volcanoes also emit volatile metals, e.g., Cd, Re, Hg, that form aerosols preserved in contemporaneous sediments. Trace metals, such as Cd, accumulate in sediments, where the excess Cd reflects the intensity of volcanic emissions. In such instances, high frequency, low effusion rate eruptions result in low Cd enrichments, whereas low frequency, high effusion rate eruptions result in high Cd enrichments in sediments. To constrain the eruption tempo of the Deccan, we have performed measurements of elemental abundances on the stratigraphically well-preserved KPg section at Elles, Tunisia. In this report, we conducted a high-resolution study of ~ 90 samples covering ~ 20 ka above the KPg boundary to ~ 350 ka below the KPg boundary. Elemental compositions for ~ 50 elements of Elles sediments were obtained by solution ICP-MS. In some samples, particularly sediments from 100 ka period preceding the boundary, Cd enrichments were eight times that of the upper continental crust (UCC). A lack of correlation between Cd and TOC, Zn, P2O5, and Mo below the boundary suggest the Cd enrichments are not from an influx of biogenic detritus nor from organic burial. Above the boundary, normal shale Cd values representing 25 ka are interpreted here to represent the period between the Ambenali and Poladpur phases. Cadmium as a tracer relates foram-based chronology with the intensity of the Deccan eruption.

How to cite: Sillitoe-Kukas, S., Humayun, M., Adatte, T., and Keller, G.: Cadmium as a tracer of volcanism at the Cretaceous-Paleogene boundary, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-16993,, 2023.