25 Refining the Cambrian—Biotas, Multiproxy Correlations, Workable Global Divisions, and Paleogeography: Discussions in Honor of Fred Sundberg

Eumetazoan diversification and origin of relatively modern marine ecosystems make the Cambrian a key Phanerozoic interval. This session focuses on the correlation significance of improved chemostratigraphic, biostratigraphic, astrochronologic, atmospheric, and oceanic syntheses; geochronology; and new paleogeographic and paleoclimatologic work.

Sunday, 19 October 2025
8:00 AM - 12:00 PM
HBGCC, 305

Integrated Stratigraphy of the Terminal Ediacaran and Basal Cambrian Periods, Northwestern Kalahari and Southwestern Laurentia

Paper number: 25-1
Program: Technical Sessions
Time: 8:05 AM – 8:25 AM

Authors

Abstract

The basal Cambrian Period broadly marks the radiation of motile bilaterian and skeletal eumetazoans, but significant uncertainty remains in reconstructing the tempo, diachroneity, and correlations of biostratigraphy and geochemical changes across the Ediacaran-Cambrian transition. Here, I review integrated geochronology, chemostratigraphy, and biostratigraphy data from strata spanning this time on southwestern Laurentia and northwestern Kalahari cratons (modern coordinates) within the context of tectonic basin evolution. While broader questions persist regarding a practical definition for the Ediacaran-Cambrian boundary, holistic evaluation of existing chronostratigraphy and index taxa frameworks help to constrain the base of Cambrian Period. More importantly, these data sets shed light on patterns and rates of evolutionary and ecological change during this interval.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412644

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