Climate variability in the western Mediterranean between 121 and 67 ka derived from a Mallorcan speleothem record

Abstract

The western Mediterranean region is exceptionally vulnerable to predicted climate changes of increasing temperature and aridity. Characterizing past climate oscillations since the last interglacial (LIG) is critical to understand climate patterns during the present warm period. Here we present an accurately dated speleothem record (CAM-1) of paleoclimate between 121 and 67 ka from the island of Mallorca. The growth history combined with the isotopic record and mineral changes, provides evidence of dramatic climatic shifts in the western Mediterranean. Isotopic equilibrium deposition was assessed by Hendy tests and by comparing the δ18O in modern drip water with newly precipitated calcite. We argue that variability of δ18O in CAM-1 is mainly related to changes in source of precipitation, whereas high δ13C values reflect a dry climate. Calcite rather than aragonite growth is related to cooler, drier climate. The MIS 5e/5d transition, C24, C23, and C21 cold events concomitantly recorded in CAM-1, ODP 984, and NGRIP highlights the teleconnection between high and mid-latitudes in the Northern Hemisphere. Our record reveals a prolonged aridity during MIS 5c and a sudden climate shift from drier to wetter conditions beginning with MIS 5b. A growth hiatus at 67 to 53 ka probably marks the driest period, after which slow calcite growth indicates markedly drier climate during the last glacial and Holocene than during MIS 5. Many of the significant changes in growth rates and stable isotopic composition are synchronous with events that are likely driven by regional climate and large circulation patterns linked to the North Atlantic.