Decadal-to-centennial scale variations during the Holocene reconstructed from sediment core D13902, supplement to: Rodrigues, Teresa; Grimalt, Joan O; Abrantes, Fatima F; Flores, José-Abel; Lebreiro, Susana Martin (2009): Holocene interdependences of changes in sea surface temperature, productivity, and fluvial inputs in the Iberian continental shelf (Tagus mud patch). Geochemistry, Geophysics, Geosystems, 10(7), Q07U06


Sea surface temperature (SST), marine productivity, and fluvial input have been reconstructed for the last 11.5 calendar (cal) ka B.P. using a high-resolution study of C37 alkenones, coccolithophores, iron content, and higher plant n-alkanes and n-alkan-1-ols in sedimentary sequences from the inner shelf off the Tagus River Estuary in the Portuguese Margin. The SST record is marked by a continuous decrease from 19C, at 10.5 and 7 ka, to 15C at present. This trend is interrupted by a fall from 18C during the Roman and Medieval Warm Periods to 16C in the Little Ice Age. River input was very low in the early Holocene but increased in the last 3 cal ka B.P. in association with an intensification of agriculture and deforestation and possibly the onset of the North Atlantic Oscillation/Atlantic Multidecadal Oscillation modes of variability. River influence must have reinforced the marine cooling trend relative to the lower amplitude in similar latitude sites of the eastern Atlantic. The total concentration of alkenones reflects river-induced productivity, being low in the early Holocene but increasing as river input became more important. Rapid cooling, of 1–2C occurring in 250 years, is observed at 11.1, 10.6, 8.2, 6.9, and 5.4 cal ka B.P. The estimated age of these events matches the ages of equivalent episodes common in the NE Atlantic– Mediterranean region. This synchronicity reveals a common widespread climate feature, which considering the twentieth century analog between colder SSTs and negative North Atlantic Oscillation (NAO), is likely to reflect periods of strong negative NAO.

Related Identifier
Metadata Access
Creator Rodrigues, Teresa; Grimalt, Joan O; Abrantes, Fatima F; Flores, José-Abel; Lebreiro, Susana Martin
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2011
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Language English
Resource Type Supplementary Dataset
Format text/tab-separated-values
Size 428 data points
Discipline Earth System Research
Spatial Coverage (-9.335 LON, 38.554 LAT); Portuguese Margin