Hydrological Impact of Heinrich Events in the Subtropical Northeast Atlantic

Abstract

Reconstructing the impact of Heinrich events outside the main belt of ice rafting is crucial to understanding the underlying causes of these abrupt climatic events. A high-resolution study of a marine sediment core from the Iberian margin demonstrates that this midlatitude area was strongly affected both by cooling and advection of low-salinity arctic water masses during the last three Heinrich events. These paleoclimatic time series reveal the internal complexity of each of the last three Heinrich events and illustrate the value of parallel studies of the organic and inorganic fractions of the sediments.

The coastal archives of the last 15ka in the Atlantic–Mediterranean Spanish linkage area: Sea level and climate changes

“…Comparing the results drawn from the sedimentary sequences exposed in the cliffs and the evolution of SSTs proposed from marine drilIings (Bard et al, 2000;Cacho et al, 2002), it seems clear that the LGM was not a cold period in south Iberia. In contrast, SSTs descended notably during both the Heinrich event 1 ('"'-' 17.6 16 cal ka BP) and the Younger Dryas ('"'-'12calkaBP), and we suggest that they were probably recorded as arid periods in the coastal zones.…”

“…Much information comes from coastal sectors studied in previous papers (e.g., Zazo et al, 1994Zazo et al, , 1999aZazo et al, c, 2005Borja et al, 1999;Dabrio et al, 1999Dabrio et al, , 2000Goy et al, 1996Goy et al, , 2003Lario et al , 2000Lario et al , , 2002Luque, 2002;YIl et al, 2003), and from Doñana-Huelva (Rodrí-guez-Ramírez et al, 1996Ruiz et al, 2005;Cáceres et al, 2006). The paper also ineludes data from Portuguese (Bard et al, 2000); M39-008 (Cacho et al, 2001; MD95-2043 (Cacho et al, 1999(Cacho et al, , 2001Sánchez-Goñi et al, 2002);H-658 C (de Menocal et al, 2000). coastal estuaries (Boski et al, 2002, in press), and the Ebro delta (Somoza et al, 1998), which augment the number of environments.…”

“…1). The reconstruction of SSTs in the Portuguese margin (e.g., Bard et al, 2000;Pailler and Bard, 2002), the Alboran Sea (Cacho et al, 1999) and the MidAtlantic at the same latitude (Chapman and Shackleton, 1998), recorded LGM winter temperatures that are only '"'-'5 oC less than modern SSTs, i.e., similar to mild periods (Bard et al, 2000). Study of the Spanish continental margin by Cacho et al (1999Cacho et al ( , 2001Cacho et al ( , 2002 revealed the occurrence of ice-rafted debris (IRD) during Heinrich events in the Gulf of Cadiz and polar waters in the Alboran Sea, with a decrease of SST around 12°C.…”

Expansion of subarctic water masses in the North Atlantic and Pacific oceans and implications for mid‐Pleistocene ice sheet growth

“…Both records reveal considerable variability within glacial and interglacial intervals, although glacials are largely marked by high concentrations of C 37:4 and low SSTs. As shown for the last glacial period in the North Atlantic, the %C 37:4 record in the site is bound to contain a suborbital variability linked to the occurrence of Heinrich events [Bard et al, 2000;RosellMelé, 1998]. Together with the sampling resolution across the 1 My interval of study limiting significant signal detection, and the noisy nature of the short-term signals given the sensitivity of this site to rapid changes in surface current locations, such processes would explain the lack of a clear glacial to interglacial variability in the records.…”

Pronounced interannual variability in tropical South Pacific temperatures during Heinrich Stadial 1

“…N ear the onset of the last glacial termination, a massive discharge of icebergs marked the cold Heinrich Stadial 1 (HS1) interval in the North Atlantic region that was accompanied by a weaker Atlantic meridional overturning circulation (AMOC) [1][2][3] . The extreme climate conditions during this interval were communicated throughout the Northern Hemisphere into the tropics through changes in ocean and atmospheric circulation, resulting in a weakening of the Asian Monsoon and a southward shift of the Intertropical convergence zone 3 .…”