A billion years of temperature variability: a key driver of Earth’s
The habitability and ecology of Earth is fundamentally shaped by surface
temperature, but the temperature history of our planet is not easily
reconstructed before the evolution of early biomineralizing animals.
This work presents a billion year, high-resolution, mineral-specific
record of oxygen isotope measurements in shallow marine rocks.
Clumped-isotope paleothermometry results from four minerals resolves
previous ambiguity with seawater oxygen isotope composition and confirms
that long-term cooling punctuated by higher-frequency variations 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. Key differences in the
dolomite oxygen isotope record exist between the Neoproterozoic
(1000–538.8 Ma) and the Phanerozoic (538.8–0 Ma), suggesting a shift
from proto-dolomite or primary dolomite to secondary dolomite formation
processes. 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.