Abstract
Abstract. Here we present high-resolution stable isotope and lamina thickness profiles as well as radiocarbon data for the Holocene stalagmite ER 76 from Grotta di Ernesto (north-eastern Italy), which was dated by combined U-series dating and lamina counting. ER 76 grew between 8 ka (thousands of years before 2000 AD) and today, with a hiatus from 2.6 to 0.4 ka. Data from nine meteorological stations in Trentino show a significant influence of the North Atlantic Oscillation (NAO) on winter temperature and precipitation in the cave region. Spectral analysis of the stable isotope signals of ER 76 reveals significant peaks at periods of 110, 60–70, 40–50, 32–37 and around 25 a. Except for the cycle between 32 and 37 a all periodicities have corresponding peaks in power spectra of solar variability, and the 25-a cycle may correspond to NAO variability. This suggests that climate variability in northern Italy was influenced by both solar activity and the NAO during the Holocene. Six periods of warm winter climate in the cave region were identified. These are centred at 7.9, 7.4, 6.5, 5.5, 4.9 and 3.7 ka, and their duration ranges from 100 to 400 a. The two oldest warm phases coincide with the deposition of sapropel S1 in the Mediterranean Sea indicating that the climate in the cave region was influenced by this prominent pluvial phase in the Mediterranean area. For the younger warm phases it is difficult to establish a supra-regional climate pattern, and some of them may, thus, reflect regional climate variability. This highlights the complexity of regional and supra-regional scale Holocene climate patterns.
Highlights
Based on isotopic records from Greenland ice cores (e.g., North Greenland Ice Core Project members, 2004), the Holocene appears as a relatively stable climatic period compared to the large climate fluctuations during the last glacial period
We present high-resolution stable isotope and lamina thickness profiles as well as radiocarbon data for the Holocene stalagmite ER 76 from Grotta di Ernesto, which was dated by combined U-series dating and lamina counting
On the basis of lake-level fluctuations, Magny et al (2003) hypothesised that during Holocene cooling phases, marked by icerafted debris (IRD) events in the North Atlantic (Bond et al, 2001), more humid conditions prevailed in European midlatitudes while at the same time, the regions north and south of this area experienced drier conditions
Summary
Based on isotopic records from Greenland ice cores (e.g., North Greenland Ice Core Project members, 2004), the Holocene appears as a relatively stable climatic period compared to the large climate fluctuations during the last glacial period. The complexity of Holocene climate patterns in central and southern Europe is, for instance, well exemplified by the work of Davis et al (2003), Magny et al (2003, 2006) and Drysdale et al (2006). D. Scholz et al.: Holocene climate variability in north-eastern Italy of consistency in the way specific regions respond to IRD events” by comparing the oxygen isotope, trace element and organic fluorescence record of a Holocene flowstone from central-western Italy with marine sediment cores from the North Atlantic and speleothems from the Middle East. Magny et al (2006) identified a complex regional-scale pattern between 5.6 and 5.3 ka (thousands of years before 2000 AD) with cooler and wetter conditions in central Europe, cold conditions in eastern Europe and dry conditions in southern Europe. The complexity of all these phenomena is likely to be reflected in climate proxy records and may even be predominant over global climate signals
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