The Iberian-Roman Humid Period (2600-1600 cal yr BP) in the Zonar Lake varve record (Andalucia, southern Spain)

The Iberian-Roman Humid Period (IRHP, 2600-1600 cal yr BP), is the most humid phase of the last 4000 yr in southern Spain as recorded in the sedimentary sequence of Zonar Lake (37 degrees 29'00 '' N, 4 degrees 41'22 '' W, 300 m a.s.l.). A varve chronology supported by several AMS C-14 dates allows study of the lake evolution at annual scale in response to human impact and climate changes. There are four climate phases within this period: i) gradual transition (2600-2500 yr ago. 650-550 BC) from a previous and period; ii) the most humid interval during the Iberian-Early Roman Epoch (2500-2140 yr ago, 550-190 BC) iii) an and interval during the Roman Empire Epoch (2140-1800 yr ago, 190 BC AD 150): and iv) a humid period synchronous with the decline of the Roman Empire (1800-1600 yr ago, AD 150-350). Varve thickness and geochemical proxies show a multi-decadal cyclicity similar to modern North Atlantic Oscillation (NAO) (60, 20 years) and solar variability cycles (11 yr). The timing and the structure of this humid period is similar to that described in Eastern Mediterranean and northern European sites and supports the same large-scale climate control for northern latitudes and the Mediterranean region. (c) 2008 University of Washington. All rights reserved.