The TEX 86 proxy, based on the distribution of marine isoprenoidal glycerol dialkyl glycerol tetraether lipids (GDGTs), is increasingly used to reconstruct sea surface temperature (SST) during the Eocene epoch (56.0-33.9 Ma). Here we compile published TEX 86 records, critically reevaluate them in light of new understandings in TEX 86 palaeothermometry, and supplement them with new data in order to evaluate long-term temperature trends in the Eocene. We investigate the effect of archaea other than marine Thaumarchaeota upon TEX 86 values using the branched-to-isoprenoid tetraether index (BIT), the abundance of GDGT-0 relative to crenarchaeol (%GDGT-0), and the Methane Index (MI). We also introduce a new ratio, % GDGT RS , which may help identify Red Sea-type GDGT distributions in the geological record. Using the offset between TEX 86 H and TEX 86 L (ΔH-L) and the ratio between GDGT-2 and GDGT-3 ([2]/[3]), we evaluate different TEX 86 calibrations and present the first integrated SST compilation for the Eocene (55 to 34 Ma). Although the available data are still sparse some geographic trends can now be resolved. In the high latitudes (>55°), there was substantial cooling during the Eocene (~6°C). Our compiled record also indicates tropical cooling of~2.5°C during the same interval. Using an ensemble of climate model simulations that span the Eocene, our results indicate that only a small percentage (~10%) of the reconstructed temperature change can be ascribed to ocean gateway reorganization or paleogeographic change. Collectively, this indicates that atmospheric carbon dioxide (pCO 2 ) was the likely driver of surface water cooling during the descent toward the icehouse.

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Permian continental sequences from North China contain previously unrecognized episodes of plant radiation and elevated extinction. The earliest extinction, in the Lower Shihhotse Formation (Roadian, Guadalupian), records a 45% floral species loss and is tentatively correlated with global extinctions amongst dinocephalian reptiles. Two younger extinctions are dated by correlating the Illawara Reversal and palaeomagnetic polarity sequences from Shanxi Province against global palaeomagnetic history. Missing data from the Shanxi sequence are evaluated using a novel approach estimating likely maximum and minimum sequence changes that provide age estimates for post-Illawara events in North China. The second extinction in the middle Upper Shihhotse Formation is more significant and is dated to the mid-Capitanian, with a loss of 56% of plant species coinciding with two phases of volcanism of the Emeishan Large Igneous Province in South China, previously linked to the mid-Capitanian marine mass extinction. The youngest extinction in the upper Upper Shihhotse Formation (late Capitanian to mid-Wuchapingian) is catastrophic and represents the end of range in the sequence. Changes in sedimentary facies suggest it to be related to global climatic warming and drying. Other viable causal mechanisms for the extinction episodes include plate motion and collision, global climate change, volcanism and biological competition.