The limited availability and low resolution of biostratigraphic and radiometric data in the Precambrian necessitate using marine chemostratigraphy to correlate and integrate the fragmentary stratigraphic record. We present a new composite record of the strontium isotope composition of seawater during the Neoproterozoic (1000-542 Ma) Era that is linked to a high-resolution δ13C (carbonate) compilation. The 87Sr/86Sr record consists predominantly of new and previously published data from carbonate-rich successions in northwest Canada, Svalbard, and northern Namibia. Published data from other late Neoproterozoic successions are conservatively included to fill in the Ediacaran Period (635-542 Ma). Consistent with previous compilations, the resulting strontium isotope record shows a systematic rise in 87Sr/86Sr throughout the Neoproterozoic, from as low as 0.7055 at the beginning of the era to greater than 0.7085 towards the end. Though the record remains poorly resolved and time-calibrated, it appears that declines, inflections, and rapid changes in 87Sr/86Sr all correspond to major biogeochemical or climatic events. However, this record supports neither a tight coupling between δ13C and 87Sr/86Sr via continental erosion nor widespread mountain-building as the main driver for increasing 87Sr/86Sr compositions during the Neoproterozoic. Rather, the steady rise in 87Sr/86Sr during the Neoproterozoic corresponded to the break-up of the supercontinent Rodinia.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Earth-Surface Processes
- C isotopes
- Sr isotopes