Temperature: a key driver of Earth's habitability over the last billion years

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.

Patterns of Spicule Preservation in Cambrian Sponges

“…Given the potential role that high temperature plays in spicule preservation (Figure 5), it could be expected that stem hexactinellid spicules might be taphonomically lost prior to the Cambrian. Siliceous spicule preservation peaks in the upper Cambrian during a relatively cool interval of time (Bergmann et al, 2022). The identification of these temperatures, which were last detected during two time intervals with similar cool conditions in the Ediacaran period Myr which are in between the Marinoan and Gaskiers glaciations), can aid in determining a specific time range for the search of siliceous spicules.…”