@Article{CrivellariCKHPZZSMHAOM:2018:InAmFr,
author = "Crivellari, Stefano and Chiessi, Cristiano Mazur and Kuhnert,
Henning and H{\"a}ggi, Christoph and Portilho-Ramos, Rodrigo da
Costa and Zeng, Jing-Ying and Zhang, Yancheng and Schefuß, Enno
and Mollenhauer, Gesine and Hefter, Jens and Alexandre, Felipe and
Oliveira, Gilvan Sampaio de and Mulitza, Stefan",
affiliation = "{Universidade Federal de S{\~a}o Paulo (UNIFESP)} and
{Universidade de S{\~a}o Paulo (USP)} and {University of Bremen}
and {University of Bremen} and {Universidade Federal de S{\~a}o
Paulo (UNIFESP)} and {University of Bremen} and {University of
Bremen} and {University of Bremen} and {Alfred Wegener Institute
for Polar and Marine Research} and {Alfred Wegener Institute for
Polar and Marine Research} and {Instituto Nacional de Pesquisas
Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais
(INPE)} and {University of Bremen}",
title = "Increased Amazon freshwater discharge during late Heinrich Stadial
1",
journal = "Quaternary Science Reviews",
year = "2018",
volume = "181",
pages = "144--155",
month = "Feb.",
keywords = "Heinrich Stadial 1, Amazon Basin, Continental precipitation,
Planktonic foraminifera, Lipid biomarkers.",
abstract = "The temporal succession of changes in Amazonian hydroclimate
during Heinrich Stadial 1 (HS1) (ca. 1814.7 cal ka BP) is
currently poorly resolved. Here we present HS1 records based on
isotope, inorganic and organic geochemistry from a marine sediment
core influenced by the Amazon River discharge. Our records offer a
detailed reconstruction of the changes in Amazonian hydroclimate
during HS1, integrated over the basin. We reconstructed surface
water hydrography using stable oxygen isotopes (\δ18O) and
Mg/Ca-derived paleotemperatures from the planktonic foraminifera
Globigerinoides ruber, as well as salinity changes based on stable
hydrogen isotope (\δD) of palmitic acid. We also analyzed
branched and isoprenoid tetraether concentrations, and compared
them to existing bulk sediment ln(Fe/Ca) data and vegetation
reconstruction based on stable carbon isotopes from n-alkanes, in
order to understand the relationship between continental
precipitation, vegetation and sediment production. Our results
indicate a two-phased HS1 (HS1a and HS1b). During HS1a (1816.9 cal
ka BP), a first sudden increase of sea surface temperatures (SST)
in the western equatorial Atlantic correlated with the slowdown of
the Atlantic Meridional Overturning Circulation (AMOC) and the
associated southern hemisphere warming phase of the bipolar
seesaw. This phase was also characterized by an increased delivery
of terrestrial material. During HS1b (16.914.8 cal ka BP), a
decrease in terrestrial input was, however, associated with a
marked decline of seawater \δ18O and palmitic acid
\δD. Both isotopic proxies independently indicate a drop in
sea surface salinity (SSS). A number of records under the
influence of the North Brazil Current, in contrast, indicate
increases in SST and SSS resulting from a weakened AMOC during
HS1. Our records thus suggest that the expected increase in SSS
due to the AMOC slowdown was overridden by a two-phased positive
precipitation anomaly in Amazonian hydroclimate.",
doi = "10.1016/j.quascirev.2017.12.005",
url = "http://dx.doi.org/10.1016/j.quascirev.2017.12.005",
issn = "0277-3791",
language = "en",
targetfile = "crivellari_increased.pdf",
urlaccessdate = "27 abr. 2024"
}