DEVELOPING A DECADAL-SCALE STALAGMITE RECORD OF HYDROCLIMATE AND ATMOSPHERIC VARIABILITY FOR WESTERN IBERIA (PORTUGAL) DURING THE LATE HOLOCENE
This project utilizes multiple actively growing, precipitation-sensitive stalagmites collected from Buraca Gloriosa, a cave in central Portugal, which is located within the high-pressure belt of the wNAO system (~100 km from Lisbon). This provides the opportunity to further evaluate the hydroclimate during the MCA and the LIA intervals. These new records will complement other proxy data and allow us to develop a more robust understanding of the wNAO system during the late Holocene.
The Buraca Gloriosa cave is instrumented inside and out yielding relative humidity, temperature, and pressure data. Additionally, a dripcounter was installed to quantify infiltration rates. Inside the cave, temperature, pressure, and relative humidity (at or near 100%) change very little throughout the year. Uranium-Thorium disequilibrium methods provide a precise age model for the stalagmites. Stable oxygen and carbon isotopic ratios from microsampled stalagmite carbonate suggest that a large shift in hydroclimate occurred within the early MCA (ca. AD 1000) at this location, which was followed by a less pronounced change in hydroclimate around AD 1400 possibly related to the wNAO.