FN Archimer Export Format
PT J
TI Terrigenous input off northern South America driven by changes in Amazonian climate and the North Brazil Current retroflection during the last 250 ka
BT 
AF GOVIN, A.
   CHIESSI, C. M.
   ZABEL, M.
   SAWAKUCHI, A. O.
   HESLOP, D.
   HOERNER, T.
   ZHANG, Y.
   MULITZA, S.
AS 1:1;2:2;3:1;4:3;5:4;6:1;7:1;8:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany.
   Univ Sao Paulo, Sch Arts Sci & Humanities, Sao Paulo, Brazil.
   Univ Sao Paulo, Inst Geosci, Dept Sedimentary & Environm Geol, Sao Paulo, Brazil.
   Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT, Australia.
C2 UNIV BREMEN, GERMANY
   UNIV SAO PAULO, BRAZIL
   UNIV SAO PAULO, BRAZIL
   UNIV AUSTRALIAN NATL, AUSTRALIA
IN DOAJ
IF 3.382
TC 63
UR https://archimer.ifremer.fr/doc/00291/40230/38675.pdf
   https://archimer.ifremer.fr/doc/00291/40230/38676.pdf
LA English
DT Article
CR IMAGES 1-MD101
BO Marion Dufresne
AB We investigate changes in the delivery and oceanic transport of Amazon sediments related to terrestrial climate variations over the last 250 ka. We present high-resolution geochemical records from four marine sediment cores located between 5 and 12 degrees N along the northern South American margin. The Amazon River is the sole source of terrigenous material for sites at 5 and 9 degrees N, while the core at 12 degrees N receives a mixture of Amazon and Orinoco detrital particles. Using an endmember unmixing model, we estimated the relative proportions of Amazon Andean material ("%-Andes", at 5 and 9 degrees N) and of Amazon material ("%-Amazon", at 12 degrees N) within the terrigenous fraction. The %-Andes and %-Amazon records exhibit significant precessional variations over the last 250 ka that are more pronounced during inter-glacials in comparison to glacial periods. High %-Andes values observed during periods of high austral summer insolation reflect the increased delivery of suspended sediments by Andean tributaries and enhanced Amazonian precipitation, in agreement with western Amazonian speleothem records. Increased Amazonian rainfall reflects the intensification of the South American monsoon in response to enhanced land-ocean thermal gradient and moisture convergence. However, low %-Amazon values obtained at 12 degrees N during the same periods seem to contradict the increased delivery of Amazon sediments. We propose that reorganizations in surface ocean currents modulate the northwestward transport of Amazon material. In agreement with published records, the seasonal in duration) during cold substages of the last 250 ka (which correspond to intervals of high DJF or low JJA insolation) and deflects eastward the Amazon sediment and freshwater plume.
PY 2014
PD APR
SO Climate Of The Past
SN 1814-9324
PU Copernicus Gesellschaft Mbh
VL 10
IS 2
UT 000335374600029
BP 843
EP 862
DI 10.5194/cp-10-843-2014
ID 40230
ER

EF