|The CLIMKARST Project|
|Rapid climate oscillations recorded in karst deposits from Romania as revealed by isotopic and paleomagnetic proxies|
|supported through the CEEX 627/2005 Grant|
|The CLIMKARST Project was concluded at August 1, 2008, and the website has been updated in order to reflect our main results. We thank to all colleagues and collaborators from around the world for their help to our research!|
|Sedimentary deposits from caves (sediments, calcite formations i.e. speleothems, fossil remains) are some of the most valuable archives which include various proxies that bear paleoclimatic and paleogeographic significance. Within the very stable microclimate typical for deep-cave settings, and in the absence of the erosional agents that act at groundís surface, cave deposits are preserving valuable records such as the isotopic signal of Oxygen, which may reflect the regional variations of temperature; the isotopic signal of Carbon and the pollen grains, which are significant for the paleovegetation; the isotopic signal of some minor elements from fossil remains (e.g. 87Sr/86Sr, 44Ca/40Ca) which are significant for populations migrations and plaeodiet; magnetic susceptibility of deposits indicative for paleoprecipitations and paleotemperatures. Compared with other continental or oceanic deposits, speleothems have the advantage that they can be dated with high precision by means of U-series methods which extends the ~45 ka limit of the radiocarbon back to ~700 ka. This limit can be further extended by using the paleomagnetic signal from speleothems and, further on, by using the 238U/234U ratio ó back to 1.2 to 1.5 Ma.
U-series dating allows reconstructing with high precision the rapid climate oscillations, with durations as small as hundreds or even tens of years during the Upper Pleistocene and the Holocene. The analysis of these oscillations from Romania and their correlation with synchronous profiles from the rest of Europe complete the big picture of the atmospheric and oceanic circulation, may allow the refinement of Global Circulation Models and medium- and short-term forecasts of the climate changes that affect the Earth.
The CLIMKARST project aimed to establish several climate reference-profiles for the Holocene and the Upper and Middle Pleistocene, based upon the isotopic analysis and dating of speleothems form Southern and Western Carpathians correlated with the analysis of the paleomagnetic signal from speleothems and cave sediments and with the complex study of fossil remains accumulations. We analyzed deposits whose general time frame was previously established by preliminary datings and concentrate on several periods characterized by rapid climate changes, such as the Holocene or the marine isotope stages (MIS) 3 and 5. The project implied the work of a multi-disciplinary team which included speleologists, mineralogists, paleontologists, physicists and takes advantage of the expertise and, partially, the infrastructure needed for modern analytical techniques, such as mass-spectrometry U-series dating, paleomagnetic studies, etc.