Lateglacial-Middle Holocene Stable Isotope Records in Two Coeval Stalagmites from the Bihor Mountains, NW Romania

Abstract

Oxygen and carbon stable isotope records of two stalagmites from NW Romania provide a continuous climatic record between 14.8 and 5.6 ka BP. The chronology is established by 21 TIMS uranium series ages. Uncertainties in the isotope chronology range between ±20 and ±100 yr. The d18 O values are positively correlated with temperature, whereas d13 C fluctuations suggest changes in soil CO2 production. Lateglacial deposition of both stalagmites started at ~14.8 ka BP. The d18 O records subsequently show a slow decline in temperatures until 12.6 ka BP. Three warmer periods with increased soil productivity occurred at 14.5-13.9 ka BP, 13.6-13.2 ka BP, and 12.9-12.6 ka BP. Lower d18 O and high d13 C values between 12.6 and 11.4 (11.7) ka BP indicate a cold and dry climate during the Younger Dryas (GS-1). During the Early Holocene, three short cold intervals are marked on the d18 O profiles at 11.0-10.6, 10.5-10.2 and 9.4-9.1 ka BP. For the remainder of the Holocene sequence, the d18 O records show less variation between 9 and 7.8 ka BP and gradual warming from 7.6-5.6 ka BP. The speleothem records correlate with the Greenland ice core records and with other proxies throughout Europe and the North Atlantic region