Paleotemperatures based on ?18O values derived from belemnites are usually “too cold” compared to other archives and paleoclimate models. This temperature bias represents a significant obstacle in paleoceanographic research. Here we show geochemical evidence that belemnite calcite fibers composed of two distinct low-Mg phases (CP1, CP2). Phase-specific situ measurement revealed systematic offse...

Paleoecological studies enhance our understanding of biotic response to climate change because they consider timescales not accessible through laboratory or ecological studies. From 60 to 51 million years ago (Ma), global temperatures gradually warmed to the greatest sustained highs of the last 65 million years. Superimposed on this gradual warming is a transient spike of high temperature and p...

Fossil marine shells collected in southern Victoria within half a degree of latitude of 38(1/2) degrees S have been analyzed for O(18)/O(16) by mass spectroscopy, and their paleotemperatures have been determined. For the genera Chlamys, Ostrea, and Glycymeris the temperature rises from early to mid-Tertiary, then falls again to the present.

[1] We studied the seasonality of planktonic foraminifera during the Last Glacial Maximum using a foraminifera model coupled to an ecosystem model. The model suggests that the timing of the maximum seasonal production of planktonic foraminifera during the Last Glacial Maximum occurred at a different time of the year from present day. The assumption of ‘‘stable’’ seasonality through time, one of...

Glycerol dibiphytanyl glycerol tetraether (GDGT) lipids are part of the cellular membranes of Thaumarchaeota, an archaeal phylum composed of aerobic ammonia oxidizers, and are used in the paleotemperature proxy TEX86 . GDGTs in live cells possess polar head groups and are called intact polar lipids (IPL-GDGTs). Their transformation to core lipids (CL) by cleavage of the head group was assumed t...

RATIONALE Workers have shown a correlation between temperature and the pollen δ(13)C value, and therefore suggested using pollen δ(13)C values to reconstruct paleotemperature. To evaluate the potential for pollen δ(13)C values to be used as a paleotemperature proxy, it is essential to quantify the variability in pollen δ(13)C values and to evaluate the effect of temperature on pollen δ(13)C val...

This study provides a comprehensive and quantitative estimate of how global temperatures have changed during the last 540 million years. It combines paleotemperature measurements determined from oxygen isotopes with broader insights obtained changing distribution lithologic indicators climate, such as coals, evaporites , calcretes reefs, bauxite deposits. The waxing waning Earth’s great polar i...