EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

New high precision U-Pb CA-ID-TIMS zircon ages from the Ediacaran in Namibia

Fabio Messori1, Ulf Linnemann2, Mandy Hofmann2, Johannes Zieger2, Gerd Geyer3, Patricia Vickers-Rich4, and Maria Ovtcharova1
Fabio Messori et al.
  • 1Dept. of Earth Sciences, University of Geneva, Geneva, Switzerland (
  • 2Senckenberg Museum of Mineralogy and Geology, Dresden, Germany
  • 3Lehrstuhl für Geodynamik und Geomaterialforschung, Bayerische Julius-Maximilians-Universität, Würzburg, Germany
  • 4School of Earth, Atmosphere and Environment, Monash University, Melbourne (Clayton), Victoria, Australia

The Ediacaran records a transition from a planet largely dominated by microscopic organisms to macroscopic multicellular organisms during the Phanerozoic. Temporal calibration of the record of changing climates and coevally diversifying biota is crucial to understand how metazoan life gained an early foothold on Earth.

A causal link between climate-driven environmental perturbations and biotic changes is generally accepted. However, a chronological relationship is needed to prove which event acted as a trigger for the biological turnover, i.e. extinction or the development of new organizational levels. A connection between environmental perturbations associated with the appearance and disappearance of the Ediacaran biota is profoundly complicated because of the scarcity of available geochronological and chemostratigraphical records. Therefore, it is crucial to expand existing datasets for this period, particularly through additional chronology.

The Nama Group in southern Namibia serves as a unique archive for major geobiological changes across the Ediacaran–Cambrian transition exemplified by a near complete section through the terminal Ediacaran. The region exposes the full stratigraphic range of the Nama assemblage and records several environmental perturbations. Establishing a precise timeframe of the terminal Ediacaran environmental and biological changes in Nama group enables a much-enhanced understanding of the nature and rates of the evolutionary changes.

Following pioneering research by Grotzinger et al. (1995), the Ediacaran–Cambrian boundary in Namibia has recently been dated ca. 2 Ma younger than previously assumed [1]. Additional high-precision U-Pb CA-ID-TIMS zircon ages from silicified tuffs of the Nama Group allow additional insights for the timeframe of the entire terminal Nama. Our results indicate that (i) the oldest ash bed in the Zaris subbasin is 547.3 Ma old, which makes it more than 0.5 Ma younger than the previously dated tuff in the same subbasin; (ii) a newly explored section at the base of the terminal Ediacaran Spitskop Member near the MTC tower (Witpütz Nord farm) revealed a slightly younger age of 539 Ma, which permits a precise correlation of this section with the Swartpunt section and indicates the position of the Ediacaran-Cambrian boundary.

[1] Linnemann, U. et al., (2019) Terra Nova 31(1) 49-58.

How to cite: Messori, F., Linnemann, U., Hofmann, M., Zieger, J., Geyer, G., Vickers-Rich, P., and Ovtcharova, M.: New high precision U-Pb CA-ID-TIMS zircon ages from the Ediacaran in Namibia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15112,, 2021.