Solar influence and hydrological variability during the Holocene from a speleothem annual record (Molinos Cave, NE Spain)

Abstract

© 2015 John Wiley & Sons Ltd. We present a multi-proxy approach to reconstructing Holocene climate conditions in northeastern Spain based on an excellent correlation among the lamina thickness, colour parameters and isotope (δ¹⁸O and δ¹³C) variations recorded in a speleothem. An age model constructed from five U/Th dates and annual lamina counting suggests that the uppermost 14.7 cm of the MO-7 stalagmite grew between 7.2 and 2.5 ka before present but experienced a growth hiatus from 4.9 to 4.3 ka. Three spectral analysis methods were applied to 11 time series. The results reveal common solar periodicities on decennial (Gleissberg cycle) and centennial (De Vries-Suess cycle) scales. The onset of Holocene carbonate precipitation in the MO-7 stalagmite appears to be associated with a cold, wet period, whereas the hiatus and the end of growth are related to warm, dry periods. This environmental trend fits well within the regional Holocene climate.