Abstract
The habitability and ecology of Earth is fundamentally shaped by surface
temperature, but the temperature history of our planet is not easily
reconstructed, especially before the evolution of early biomineralizing
animals. This work presents a billion-year-long, high-resolution,
mineral-specific record of oxygen isotope measurements in shallow marine
rocks. Clumped isotope paleothermometry results from four minerals
resolves previous ambiguity in seawater oxygen isotope composition and
confirms that long-term cooling punctuated by short-lived temperature
extremes are dominant components of this record. We consider
post-depositional effects by comparing Phanerozoic rock and fossil
records, and identify temporal and spatial controls on alteration.
Furthermore, this record is suggestive of key differences in dolomite
(CaMg(CO3)2) formation processes between the Neoproterozoic (1000–538.8
Ma) and Phanerozoic (538.8–0 Ma), consistent with previous suggestions
based on petrographic and sedimentological observations. This record,
when viewed alongside the fossil record, suggests temperature change is
tightly coupled to extinction and origination in the history of life and
carbon cycle perturbations over the last billion years.