Leaf margin characters are strong predictors of mean annual temperature (MAT) in modern plant communities and widely used tools for reconstructing paleoclimates from fossil floras. However, the frequency of nonentire-margined species may vary dramatically between different habitats of the same forest. In this paper we explore the potential for this habitat variation to introduce error into temp...

JULY 2003, GSA TODAY ABSTRACT Atmospheric levels of CO2 are commonly assumed to be a main driver of global climate. Independent empirical evidence suggests that the galactic cosmic ray flux (CRF) is linked to climate variability. Both drivers are presently discussed in the context of daily to millennial variations, although they should also operate over geological time scales. Here we analyze t...

Banded travertines are important parts of fissure ridge systems, but studies on geochemical characterization banded limited. This study investigated the lithofacies and stable carbon oxygen isotopic features from Xiagei (southwestern China) to examine their formation mechanisms. Petrographic analyses revealed two lithotypes: thick-laminated palisade crystalline crust thin-laminated composite cr...

An empirical global core-top calibration that relates the alkenone unsaturation index U 0 37 to mean annual SST (maSST) is statistically the same as that defined for a subarctic Pacific strain of Emiliania huxleyi (CCMP1742) grown exponentially in batch culture under isothermal conditions. Although both equations have been applied widely for paleoSST reconstruction, uncertainty still stems from...

Abstract Paleotemperature proxy records are widely used to reconstruct the global climate throughout Phanerozoic and test macroevolutionary hypotheses. However, spatial distribution of these varies through time. This is problematic because heat unevenly distributed across Earth's surface. Consequently, heterogeneous sampling data has potential bias reconstructed temperature curves. We evaluated...

Causes of macroevolutionary trends in body size, such as Cope's Rule, the tendency of body size to increase over time, remain poorly understood. We used size measurements from Cenozoic populations of the ostracode genus Poseidonamicus, in conjunction with phylogeny and paleotemperature estimates, to show that climatic cooling leads to significant increases in body size, both overall and within ...