Abstract

The Late Cretaceous (late Campanian to Maastrichtian) was characterized by a variable greenhouse climate, with evidence for cooling and/or glaciation and warming events. Most of these climatic signals are derived from marine records, and knowledge of the terrestrial climate, especially in the mid-latitudes, is limited due to fragmentary geological records on continents. Here we report mid-latitude terrestrial stable oxygen and carbon isotope data from pedogenic carbonates in the nearly continuous Late Cretaceous age SK-1 core drilled in the Songliao Basin, northeastern China. Our data indicate a punctuated, mid-latitude terrestrial climate in the Late Cretaceous. We interpret the negative excursion of pedogenic carbonate δ18O in the early Maastrichtian to be the result of decreasing temperature and/or strengthened westerlies during global cooling and possible glaciation, providing valuable mid-latitude terrestrial evidence for this event. The negative δ13C isotopic excursion ca. 66 Ma is modeled as higher primary productivity caused by increasing temperature and precipitation in response to a warming climate in the latest Cretaceous. Our continuous stable isotopic records in the Songliao Basin are in accordance with previously published global Late Cretaceous records of climate variability from marine and terrestrial regions, and demonstrate the sensitivity of mid-latitude terrestrial climate in a greenhouse world.

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