Speleothem growth requires humid climates sufficiently warm to stimulate soil CO2 production by plants. We compile 283 U/Th dates on 21 stalagmites from six cave systems in the NW coast of Spain to evaluate if there are patterns in stalagmite growth that are evidence of climatic forcing. In the oldest stalagmites, from marine oxygen isotope stage (MIS) 7-5, growth persists through the glacial period. Hiatuses and major reductions in growth rate occur during extreme minima in summer insolation. Stalagmites active during the last interglaciation cease growth at the MIS 5-4 boundary (74ka), when regional sea-surface temperature cooled significantly. During MIS 3, only two stalagmites grew; rates were highest between 50 and 60ka during the maximum in summer insolation. One stalagmite grew briefly at 41ka, 36.5 and 28.6ka, all during warm phases of the Dansgaard-Oeschger cycles. A pronounced Holocene optimum in stalagmite growth occurs from 9 to 6ka. The cessation of most growth by 4.1ka, coincident with broad increases in aridity over the Mediterranean and areas influenced by the North African Monsoon, suggest that regions such as NW Spain, with dominant Atlantic moisture sources, also experienced increased aridity at this time.
|Original language||English (US)|
|Number of pages||7|
|Journal||Quaternary Research (United States)|
|State||Published - Sep 2013|
Bibliographical noteFunding Information:
This work was funded by grant MEC CGL2006 13327-Co4-02, MEC CGL2010 16376, and FICYT IB08-072C1, and a DuPont Young Professor award (to H.M.S.). The work was conducted in collaboration with the GRACCIE-Consolider CSD2007-00067. U/Th dating was conducted by H.M.S., A.M., A.M.-V., and S.G-L. under the direction of R.L.E., H.C., and X.W. Field collection was conducted by H.M.S., A.M.-V., S.G-L., M.J-S., and M.J.D.-C. H.M.S. and A.M. wrote the paper.
Copyright 2013 Elsevier B.V., All rights reserved.
- U/Th dates