Data and Supplementary Information: Nelson et al., 2025, American Journal of Science

Data and Supplementary Information for "A basin in transition: ecological, environmental, and tectonic shifts across the Ediacaran–Cambrian boundary in the Nama Group, Kalahari Craton."

Lyle L. Nelson1,2*, Emily F. Smith3, Simon. A. F. Darroch4, Iona Baillie3, Jahandar Ramezani1, John E. Almond5, Roger Swart6, Dana E. Polomski1, Katherine A. Turk7

1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
2Department of Earth Science, Carleton University, Ottawa, Ontario K1S 5B6, Canada
3Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
4Senckenberg Museum of Natural History, Frankfurt 60325, Germany
5Natura Viva cc, PO Box 12410 Mill Street, Cape Town 8010, Republic of South Africa
6BlackGold Geosciences cc, P.O. Box 24287, Windhoek, Namibia
7Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA

*Corresponding author: [e-mail]

Table SI1. U-Pb isotopic data for zircon analyses from upper Swartkloofberg Formation ash bed E2107, Neint Nababeep Plateau, South Africa.

Table SI2. Carbon and oxygen isotope data of limestones from the upper Swartkloofberg Formation, Neint Nababeep Plateau, South Africa.

Figure SI1. Photographs of ash beds and dated zircons. A) Outcrop photograph of silicified ash bed in limestone of the Spitskop Member, upper Schwarzrand Subgroup, Neint Nababeep Plateau; example of the distinctive lithology of ash beds in this succession; 33 cm hammer for scale. B) Outcrop photograph of silicified ash bed (sample E2107) within stromatolite reef complex of upper Swartkloofberg Formation, Neint Nababeep Plateau; 33 cm hammer for scale. C-D) Photomicrographs of sharp euhedral zircon grains separated from sample E2107. The age of this volcanic ash bed was calculated at 537.64 ± 0.25 Ma based on the weighted mean of a statistically coherent cluster of 206Pb/238U dates from four of these zircon grains, after excluding a single older analysis interpreted to represent a detrital or xenocrystic zircon (fig. 12).