Paleohydrological dynamics in the Western Mediterranean during the last glacial cycle

Past 200 kyr hydroclimate variability in the western Mediterranean and its connection to the African Humid Periods

“…The frequency of the statistically significant changes is higher for the last 30 kyr due to the higher sample resolution in the original fossil pollen data. The statistically significant precipitation increases are termed West Mediterranean Humid Periods (WMHPs), similar to that observed by García-Alix et al 31 for the Holocene humid period recorded in the West Mediterranean between 15.5 and 5 kyr BP. Therefore, we obtained six main WMPHs, three of them divided into 2 sub-phases: WMHP-6 (180–155 kyr BP; WMHP-6.2 at 180–171 kyr BP and WMHP-6.1 at 161–155 kyr BP), WMHP-5 (136–105 kyr BP), WMHP-4 (81–60 kyr BP; WMHP-4.2 at 81–71 kyr BP and WMHP-4.1 at 66–60 kyr BP), WMHP-3 (39–29 kyr BP), WMHP-2 (27–18.5 kyr BP; WMHP-2.2 at 27–25 kyr BP and WMHP-2.1 at 23–18.5 kyr) and WMHP-1 (15.5–5 kyr BP) (Figs.…”

“…This indicates that the main water-source in western Mediterranean during these periods of high summer insolation was controlled by the Atlantic wintertime storm track activity. This is supported by the hydrogen isotopic composition of terrestrial leaf waxes of the last 35 kyr, showing that although the correlation between the δD C31 from Padul and West Africa is high, the differences in absolute values point to different precipitation sources 31 (Fig. 4 F,I).…”

“…Similar weakening of the westerlies could have also happened during glacial periods the Iberian Peninsula, providing the perfect conditions for higher MSP related with higher contribution of the local Mediterranean summer rainfall-source. This is supported by the hydrogen isotopic composition of leaf waxes in the Padul record during the last 35 kyr, suggesting a higher influence of the local Mediterranean rainfall with respect to the Atlantic source during the glacial period 31 .…”

“…4 A,H,J). Similarly, the hydrogen isotopic composition of terrestrial leaf waxes (δD C31 ) from the continental slope off Senegal for the last 45 kyr BP 51 show parallel trends with respect to the MAP and the δD C31 records from Padul 31 (Fig. 4 A,F,I), suggesting that climate in West Africa and West Mediterranean seems to be controlled by the same orbital factors.…”

“…Top panel (southern Iberia): ( A ) Reconstructed Padul MAP (mm/yr) along with the WMHPs (black horizontal lines) and HSs. Middle panel (other West/Central Mediterranean records): ( B ) our Villarquemado MAP reconstruction (mm/yr) (NE Spain), ( C ) Average MAP change (mm/yr) for southern Europe 40 , ( D ) MAP reconstruction from Lake Ohrid (Macedonia/Albania) 11 , ( E ) δ 18 O from Susah cave (N Libya) 2 , 46 , Victoria cave (SE Spain) 45 and Corchia cave (N Italy) 41 – 44 (note inverted scale), ( F ) δD C31 from Padul 31 (note inverted scale), ( G ) fluvial runoff pulses from the 64PE349-8 record (offshore Libya) 47 . Bottom panel (West Africa, North Atlantic and insolation): ( H ) age-ranges of African Humid Periods (black horizontal lines) identified by different studies: (1) Ehrmann et al 96 , (2) Grant et al 97 , (3) Skonieczny et al 98 , (4) Ziegler et al 99 and Pausata et al 48 , and (5) Kinsley et al 100 , ( I ) δD C31 from the GeoB9508-5 record (continental slope off Senegal) 51 (note inverted scale), ( J ) Humidity index from the GeoB7920-2 record (offshore Mauritania) 58 , ( K ) Pa/Th from the North Atlantic CDH19 record 61 (note inverted scale), ( L ) 37°N mean summer and winter insolation.…”