Climate information from C, N and O stable isotope analyses of mammoth bones from northern Siberia

Nineteen Late Pleistocene samples of fossil mammoth and four of horse and bison from the Leptev Sea area were studied for their C, N and O stable isotope composition. The majority of the samples have interstadial (MIS 3) ages and only two have late-glacial ages. The carbon and nitrogen isotope values are in good agreement with those previously measured on other mammoths from the same area. They seem to indicate, for the interstadial period, a stability of the climate conditions characterised by low and constant rainfall with only few oscillations. Only after the LGM are more humid conditions apparent.The calculated oxygen isotope composition of water are several per mill more positive than those of modern meteoric water in the area. They do not seem to correlate with well-established Late Pleistocene temperature changes but rather with aridity. The temporal pattern indicates a rapid increase of dry conditions after around 34 ka BP. Only the two samples dated after the LGM might indicate an effective increase in temperature.