Long-term hydrological changes in northern Iberia (4.9–0.9 ky BP) from speleothem Mg/Ca ratios and cave monitoring (Ojo Guareña Karst Complex, Spain)

摘要: An absolute-dated stalagmite from Kaite Cave (Ojo Guarena Karst Complex, N Spain) provides a nearly continuous, high-resolution record of proxy regional precipitation patterns through the 4.9–0.9 ka BP interval. This is based on Mg/Ca ratio calcite and its variation stratigraphy, which interpreted to be primarily driven by changes in amount. The calibration supported present-day monitoring carried out cave for last 10 years, reveals robust inverse relationship between inter-annual/inter-decadal variability rainfall Mg concentration dripwaters precipitating speleothems. paleoprecipitation, 2400 measurements, shows strong at inter-annual inter-decadal scales, more subtle but significant secular millennial scales. long-term paleohydrological evolution outlines five successive intervals with consistent trends, are bounded abrupt shifts precipitation. These took place 4.65, 4.2, 2.6, 1.3 BP. Significantly, maximum whole (around 4.9–4.65, 2.6–2.45, 1.3–1.1 BP) can related episodes minimum solar activity correlated cold climatic events elsewhere.