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.

Well-dated lacustrine records are essential to establish the timing and drivers of regional hydroclimate change. Searles Basin, California records the depositional history of a fluctuating saline-alkaline lake in the terminal basin of the Owens River system draining the eastern Sierra Nevada. Here we establish a U-Th chronology for the ~76-m-long SLAPP-SLRS17 core collected in 2017 based on dating of evaporite minerals. 98 dated samples comprising 9 different minerals were evaluated based on stratigraphic, mineralogic, textural, chemical and reproducibility criteria. After application of these criteria, a total of 37 dated samples remained as constraints for the age model. A lack of dateable minerals between 145-110 ka left the age model unconstrained over the penultimate glacial termination (Termination II). We thus established a tie point between plant wax δD values in the core and a nearby speleothem δ18O record at the beginning of the Last Interglacial. We construct a Bayesian age model allowing stratigraphy to inform sedimentation rate inflections. We find the >210 ka SLAPP-SRLS17 record contains five major units that correspond with prior work. The new dating is broadly consistent with previous efforts but provides more precise age estimates and a detailed evaluation of evaporite depositional history. We also offer a substantial revision of the age of the Bottom Mud-Mixed Layer contact, shifting it from ~130 ka to 178±3 ka. The new U-Th chronology documents the timing of mud and salt layers and lays the foundation for climate reconstructions.

Pre- and syn-glacial low-latitude carbonate sediments of the Elbobreen Formation, NE Svalbard, preserve evidence for dramatic climate changes associated with Cryogenian glaciations (720–635 Ma). We combine carbonate stable (δ13C, δ18O) and clumped isotope (Δ47) geochemistry with petrographic observations to assess the source of carbonate within glacial facies of the Petrovbreen Member and their environmental significance. Calcite Δ47 temperatures reflect solid-state reordering under burial temperatures, whereas dolomites record lower temperatures that vary with depositional facies. Pre-glacial dolomites have Δ47 temperatures from 48–73°C, with a reconstructed fluid δ18O value of +0.6‰ (VSMOW) in the coldest sample. Glacial dolomites comprise: (1) detrital carbonate clasts similar to pre-glacial strata in stable isotope composition, Δ47 temperature, and petrographic textures; and (2) autochthonous dolomicrite and re-worked dolomicrite clasts with heavier δ18O values and colder Δ47 temperatures of 19–44 °C. Measured dolomite temperatures likely include a component of diagenetic alteration that elevated the sample temperature above that imparted at deposition. The statistically significant difference in temperatures between precipitated matrix and re-worked detrital clasts in diamictite indicates that matrix samples preserve some component of carbonate that records early temperature differences either reflecting the primary sediments or early dolomitization and shallow lithification. The higher source fluid δ18O values in glacial carbonates is consistent with an active hydrological cycle, either through local evaporation or growth of continental ice sheets sourced from evaporation of seawater. Continued hydrological cycling and 20–30 °C offsets in temperature between glacial and non-glacial conditions constrain carbonate depositional environments in this first Cryogenian glaciation.

The potential for carbonate clumped isotope thermometry to independently constrain both the formation temperature (T∆47 ) of carbonate minerals and fluid oxygen isotope composition allows insight into long-standing questions in the Earth sciences, but remaining discrepancies between calibration schemes hamper interpretation of T∆47 measurements. To address discrepancies between calibrations, we designed and analyzed a sample suite (41 total samples) with broad applicability across the geosciences, with an exceptionally wide range of formation temperatures, precipitation methods, and mineralogies. We see no statistically significant offset between sample types, although comparison of calcite and dolomite remains inconclusive. When data are reduced identically, the regression defined by this study is nearly identical to that defined by four previous calibration studies that used carbonate-based standardization; we combine these data to present a composite carbonate-standardized regression equation. Agreement across a wide range of temperature and sample types demonstrates a unified, broadly applicable clumped isotope thermometer calibration.

Carbonate rocks on continental crust are one of Earth’s largest reservoirs of CO2 and yet the controls on their volume through time are poorly understood. Here we quantify temporal changes in preserved continental carbonate rocks over the last billion years in both global and North America-specific datasets within paleogeographic context. We find the preserved area of continental carbonate rocks increases by ~175% across the Neoproterozoic-Phanerozoic boundary ca. 539 million years ago, coincident with the rise of macroscopic, multicellular life and the evolutionary innovation of carbonate biomineralization in shallow water reefs. We demonstrate that crustal loading from carbonate sediments on one tropical paleo-continent (North America) contributes to an increase in continent-scale accommodation in the early Phanerozoic, expanding shallow marine environments. We predict this feedback between enhanced carbonate accumulation and subsidence was an important component of the termination of the Great Unconformity. These results are combined into a new conceptual model that links the changes in preserved carbonate rock volumes to the evolutionary innovation of carbonate biomineralization in a range of complex organisms. Our model implies evolutionary controls on the carbonate rock reservoir enhanced CO2 sequestration at the beginning of the Phanerozoic, with consequences for Earth’s carbon cycle, climate and habitability.