Tracking climate variability in the western Mediterranean during the Late Holocene: a multiproxy approach

Abstract

Abstract. Climate variability in the western Mediterranean is reconstructed for the last 4000 yr using marine sediments recovered in the west Algerian-Balearic Basin, near the Alboran Basin. Fluctuations in chemical and mineralogical sediment composition as well as grain size distribution are linked to fluvial-eolian oscillations, changes in redox conditions and paleocurrent intensity. Multivariate analyses allowed us to characterize three main groups of geochemical and mineralogical proxies determining the sedimentary record of this region. These three statistical groups were applied to reconstruct paleoclimate conditions at high resolution during the Late Holocene. An increase in riverine input (fluvial-derived elements -Rb/Al, Ba/Al, REE/Al, Si/Al, Ti/Al, Mg/Al and K/Al ratios), and a decrease in Saharan eolian input (Zr/Al ratio) depict the Roman Humid Period and the Little Ice Age, while drier environmental conditions are recognized during the Late Bronze Age-Iron Age, the Dark Ages and the Medieval Climate Anomaly. Additionally, faster bottom currents and more energetic hydrodynamic conditions for the former periods are evidenced by enhanced sortable silt (10-63 µm) and quartz content, and by better oxygenated bottom waters -as reflected by decreasing redox-sensitive elements (V/Al, Cr/Al, Ni/Al and Zn/Al ratios). In contrast, opposite paleoceanographic conditions are distinguished during the latter periods, i.e. the Late Bronze Age-Iron Age, the Dark Ages and the Medieval Climate Anomaly. Although no Ba excess was registered, other paleoproductivity indicators Correspondence to: V. Nieto-Moreno (vanesanieto@ugr.es) (total organic carbon content, Br/Al ratio, and organometallic ligands such as U and Cu) display the highest values during the Roman Humid Period, and together with increasing preservation of organic matter, this period exhibits by far the most intense productivity of the last 4000 yr. Fluctuations in detrital input into the basin as the main process managing deposition, reflected by the first eigenvector defined by the Principal Component Analyses, point to solar irradiance and the North Atlantic Oscillation variability as the main driving mechanisms behind natural climate variability over decadal to centennial time-scales for the last 4000 yr.

A multi-proxy perspective on millennium-long climate variability in the Southern Pyrenees

“…Exceptions to this pattern occur in the northwestern Atlantic shore of the IP (Ría de Muros, (Lebreiro et al, 2006;Galop et al, 2011) and Ría de Vigo (Kanner et al, 2012)) and also in South , revealing an intra-regional complex variability in the hydrological conditions within the IP ). An antiphase behaviour in the hydrological signal, with wet MCA and dry LIA, has also been recorded in some eastern Mediterranean lakes (Roberts et al, 2011). This Mediterranean see-saw pattern might be related to the higher influence of the NAO in westernmost areas, like the Southern Pyrenees.…”

Holocene and ‘Little Ice Age’ glacial activity in the Marboré Cirque, Monte Perdido Massif, Central Spanish Pyrenees

“…The age of this polished surface indicates that during the Medieval Climatic Anomaly (MCA, 1.15-0.65 cal ky BP) deglaciation occurred at the high altitudes in the Pyrenees. The MCA was warmer and relatively more arid period in the Iberian Peninsula as indicated by lacustrine records from NE Spain (Morellón et al, 2012;Corella et al, 2012Corella et al, , 2013, and southern Spain (Zoñar and La Moska lakes: Martín-Puertas et al, 2008;Oliva and Gómez Ortiz, 2012), marine sediment near the Alboran basin (Martín-Puertas et al, 2010;Nieto-Moreno et al, 2011), and fossil pollen data from southern France to southeast Spain (Jalut et al, 2000). According to Moreno et al (2012), the MCA in the Iberian Peninsula was characterized by decreased lake levels, fewer floods, major Saharan aeolian fluxes, and less fluvial input to marine basins.…”

Climate reconstruction for the last two millennia in central Iberia: The role of East Atlantic (EA), North Atlantic Oscillation (NAO) and their interplay over the Iberian Peninsula

“…2) might be associated with frequent autumn/summer storms in this region. In the southern IP and western Mediterranean region, the marine (Alboran Sea and west Algerian-Balearic Basin) and terrestrial records (Zoñar Lake) displayed prevalent wet conditions (Martín-Puertas et al, 2008, 2010Nieto-Moreno et al, 2011).…”