Four climate cycles of recurring deep and surface water destabilizations on the Iberian margin.
Centennial climate variability over the last ice age exhibits clear bipolar behavior. High-resolution analyses of marine sediment cores from the Iberian margin trace a number of associated changes simultaneously. Proxies of sea surface temperature and water mass distribution, as well as relative biomarker content, demonstrate that this typical north-south coupling was pervasive for the cold phases of climate during the past 420,000 years. Cold episodes after relatively warm and largely ice-free periods occurred when the predominance of deep water formation changed from northern to southern sources. These results reinforce the connection between rapid climate changes at Mediterranean latitudes and century-to-millennial variability in northern and southern polar regions.
Martrat
Belen
B
Department of Environmental Chemistry, Chemical and Environmental Research Institute of Barcelona, Spanish National Research Council (IIQAB-CSIC), 08034 Barcelona, Spain.
Grimalt
Joan O
JO
Shackleton
Nicholas J
NJ
de Abreu
Lucia
L
Hutterli
Manuel A
MA
Stocker
Thomas F
TF