http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 Evidence for obliquity forcing of glacial termination II http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7742 Variations in the intensity of high-latitude Northern Hemisphere summer insolation, driven largely by precession of the equinoxes, are widely thought to control the timing of Late Pleistocene glacial terminations. However, recently it has been suggested that changes in Earth’s obliquity may be a more important mechanism. We present a new speleothem-based North Atlantic marine chronology that shows that the penultimate glacial termination (Termination II) commenced 141,000 ± 2500 years before the present, too early to be explained by Northern Hemisphere summer insolation but consistent with changes in Earth’s obliquity. Our record reveals that Terminations I and II are separated by three obliquity cycles and that they started at near-identical obliquity phases. 2011-05-20T05:50:32.197Z ]]> Enhanced rainfall in the Western Mediterranean during deposition of sapropel S1: stalagmite evidence from Corchia cave (Central Italy) http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:3317 A stable isotope record from a stalagmite collected from Antro del Corchia cave (Apuan Alps, Central Italy), supported by 17 uranium-series ages, indicates enhanced regional rainfall between ca 8.9 and 7.3 kyr cal. BP at the time of sapropel S1 deposition. Within this phase, the highest rainfall occurred between 7.9 and 7.4 kyr cal. BP. Comparison with different marine and lake records, and in particular with the Soreq Cave record (Israel), suggests substantial in-phase occurrence of enhanced rainfall between the Western and Eastern Mediterranean basins. There is no convincing evidence for major climatic change at the time of the “8.2 kyr event”. 2010-04-27T05:00:33.347Z ]]> The environmental features of the Monte Corchia cave system (Apuan Alps, central Italy) and their effects on speleothem growth http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:5267 The Monte Corchia cave system, one of the most famous and popular caves in Italy, has in recent times been the subject of investigation on its speleothems as paleoclimate archives. This paper describes the geology, geomorphology and water chemistry of the cave system with the aim to elucidate the processes that have generated these speleothems and the properties they contain that are so useful for paleoclimatology. Some general conclusions can be drawn: i) the Corchia system is a cave developed over different altitudes during progressive uplift of the mountain chain in which it is located, probably under drainage conditions very different to those of the present. This has allowed the development of a large (ca. 60 km) and deep (-1187 m) karst system; ii) the dewatering phases have left the deepest chambers far away from clastic input and with long drip pathways; iii) the peculiar geological context has permitted the water to intercept and dissolve a significant source of U (still unknown) that facilitates radiometric dating; iv) in the last 1 Ma at least, no significant changes have occurred in the relief and in the epikarst, in the sense that speleothems have grown under very similar conditions. In addition the extremely low Ca concentration of drip waters have permitted low speleothem growth rates and, at least for the “Galleria delle Stalattiti”, the zone under paleoclimate studies, a stable plumbing system (i.e. chemistry and stable isotopes of drip waters) has produced calcite close to isotopic equilibrium. 2010-04-27T04:32:56.359Z ]]>