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Past orbital analogues to the current interglacial, such as Marine Isotope Stage 19c (MIS 19c, ca. 800 ka), can provide reliable reference intervals for evaluating the timing and the duration of the Holocene and factors inherent in its climatic progression. Here we present the first high-resolution paleoclimatic record for MIS 19 anchored to a high-precision 40Ar/39Ar chronology, thus fully independent of any a priori assumptions on the orbital mechanisms underlying the climatic changes. It is based on the oxygen isotope compositions of Italian lake sediments showing orbital- to millennial-scale hydrological variability over the Mediterranean between 810 and 750 ka. Our record indicates that the MIS 19c interglacial lasted 10.8 ± 3.7 k.y., comparable to the time elapsed since the onset of the Holocene, and that the orbital configuration at the time of the following glacial inception was very similar to the present one. By analogy, the current interglacial should be close to its end. However, greenhouse gas concentrations at the time of the MIS 19 glacial inception were significantly lower than those of the late Holocene, suggesting that the current interglacial could have already been prolonged by the progressive increase of the greenhouse gases since 8-6 ka, possibly due to early anthropogenic disturbance of vegetation.

Speleothems are well-proven archives of terrestrial climate variation, recording mean temperature, rainfall, and surface vegetation data at subannual to millennial resolution. They also form within the generally stable environment of caves, and thus may remain remarkably well preserved for many millions of years and, most important, can be dated radiometrically to provide robust chronologies that do not rely on orbital tuning, ice-flow modeling, or estimates of sediment deposition rates. The recent adaptation of the U-Pb dating technique to speleothems has greatly extended their potential as paleoclimate recorders back into the more distant geological past, well beyond the ~500 k.y. limit previously imposed by U-series techniques, but the opportunities presented by these new methods have yet to be fully explored. As an extreme example, here we report on samples recovered from Permian cave fills, the oldest radiometricaily dated speleothems SO far documented. Using state of the art analytical techniques it is possible to determine not only their age and state of preservation, but also to extract apparently nearly pristine climate proxy data. Armed with these methods, it now seems reasonable to apply the lessons learned from more recent speleothems to ancient materials, wherever they can be found, and of whatever age, to generate snapshots of paleoclimate that can be used to greatly refine the records preserved within the sediments and fossils of the time. doi: 10.1130/G30354.1

Evidence of millennial-scale cold events following the last interglacial are well preserved in North Atlantic marine cores, Greenland ice, and pollen records from Europe. However, their timing was previously undetermined by radiometric dating. We report the first precise radiometric ages for two such events, C23 (105.1 [+ or -] 0.9 ka to 102.6 [+ or -] 0.8 ka) and C24 (112.0 [+ or -] 0.8 ka and 108.8 [+ or -] 1.0 ka), based on stable carbon and oxygen isotope measurements on a stalagmite from Italy (CC28). In addition to providing new information on the duration of these events in southern Europe, the age data provide invaluable tuning points for the Melisey I (C24) and Montaigu (C23) pollen zones identified in western Europe. The former event is of particular significance because it represents the end of the Eemian interglacial forest phase in western Europe. The new age data will also allow fine tuning of the timing and duration of Greenland stadial 24 (equivalent to C23) in the North Greenland Ice Core Project ice core and, via a common gas-age chronology, tuning of the Vostok and EPICA (European Project for Ice Coring in Antarctica) ice cores. Keywords: speleothems, U-series dating, ice-rafted debris, last interglacial, paleoclimate.

A severe drought in parts of low-latitude northeastern Africa and southwestern Asia ~4200 yr ago caused major disruption to ancient civilizations. Stable isotope, trace element, and organic fluorescence data from a calcite flowstone collected from the well-watered Alpi Apuane karst of central-western Italy indicate that the climatic event responsible for this drought was also recorded in mid-latitude Europe. Although the timing of this event coincides with an episode of increased ice-rafted debris to the subpolar North Atlantic, the regional ocean-atmosphere response seems atypical of similar Holocene icerafting events. Furthermore, comparison of the flowstone data with other regional proxies suggests that the most extreme part of the dry spell occurred toward the end of a longer-term climate anomaly. Keywords: speleothems, Holocene, drought, geochemistry, Italy.