New quantitative palaeocolimate data for the Late Cretaceous Arctic: evidence for a warm polar ocean

Physiognomic analysis of four taphofloras (one from the Coniacian of N. Alaska, one from the Coniacian of Kamchatka, one from the Turonian of Kamchatka, and one from the Turonian of Novaya Sibirʹ Island) using the CLAMP technique of Wolfe (1993) yielded quantitative data on the mean annual, warm month mean, and cold month mean temperatures, the length of the growing season, mean annual precipitation, mean growing season precipitation, mean monthly growing season precipitation and the precipitation during the three consecutive driest months. These new results represent the first application of multivariate statistical analysis of foliar physiognomy to determine palaeoclimatic parameters (CLAMP) to Arctic Cretaceous floras and demonstrate its robustness even in the context of vegetation which has no living analogues. These new estimates were comparable to those from previous quantitative or qualitative sedimentological or palaeobotanical data where they were available, but offer greater measurable precision. sults also suggest that an Arctic Ocean with a winter surface temperature of approximately 6°C maintained N. Alaska coastal temperatures above freezing, locally reversing the equator to pole temperature gradient; a phenomenon not seen in the northern proto-Pacific. This anomalously warm Arctic Ocean could have been produced by marine poleward heat transport. Precipitation in Alaska, Kamchatka and Novaya Sibirʹ Island was predicted to have been high (e.g. 1760 mm/yr in the Coniacian of N. Alaska) reflecting a very weak polar high pressure cell and substantially different precipitation patterns to Present.