FN Archimer Export Format
PT J
TI Millennial-scale variability of deep-water temperature and delta O-18(dw) indicating deep-water source variations in the Northeast Atlantic, 0-34 cal. ka BP
BT 
AF SKINNER, LC
   SHACKLETON, NJ
   ELDERFIELD, H
AS 1:1;2:1;3:2;
FF 1:;2:;3:;
C1 Univ Cambridge, Dept Earth Sci, Godwin Inst Quaternary Res, Cambridge CB2 3SA, England.
   Univ Cambridge, Dept Earth Sci, Cambridge CB2 3EQ, England.
C2 UNIV CAMBRIDGE, UK
   UNIV CAMBRIDGE, UK
IF 2.623
TC 113
UR https://archimer.ifremer.fr/doc/00225/33654/32087.pdf
LA English
DT Article
CR IMAGES 1-MD101
   IMAGES V LEG 1-MD114
   IMAGES V LEG 4-MD114
   MD 123 / GEOSCIENCES 1
BO Marion Dufresne
DE ;deep-water temperature;Mg/Ca;termination I;thermohaline circulation;paleoceanographycal and chemical : trace elements;oceanography : biological and chemical : trace elements;oceanography : biological and chemical : stable isotopes
AB Paired measurements of Mg/Ca and delta(18)O(cc) (calcite delta(18)O) in benthic foraminifera from a deep-sea core recovered on the Iberian Margin (MD99-2334K; 37degrees 48'N, 10degrees10'W; 3,146 m) have been performed in parallel with planktonic delta(18)O(cc) analyses and counts of ice-rafted debris (IRD). The synchrony of temperature changes recorded in the Greenland ice cores and in North Atlantic planktonic delta(18)O(cc) allows the proxy records from MD99-2334K to be placed confidently on the GISP2 time-scale. This correlation is further corroborated by AMS C-14-dates. Benthic Mg/Ca measurements in MD99-2334K permit the reconstruction of past deep-water temperature (T-dw) changes since -34 cal. ka BP (calendar kiloyears before present). Using these T-dw estimates and parallel benthic delta(18)O(cc) measurements, a record of deepwater delta(18)O (delta(18)O(dw)) has been calculated. Results indicate greatly reduced T-dw in the deep Northeast Atlantic during the last glaciation until -15 cal. ka BP, when T-dw warmed abruptly to near-modern values in parallel with the onset of the Bolling-Allerod interstadial. Subsequently, Tdw reverted to cold glacial values between -13.4 and -11.4 cal. ka BP, in parallel with the Younger Dryas cold reversal and the H0 ice-rafting event. Similar millennial-scale T-dw changes also occurred during the last glaciation. Indeed, throughout the last -34 cal. ka, millennial delta(18)O(dw) and T-dw changes have remained well coupled and are linked with IRD pulses coincident with Heinrich events 3, 2, 1, and the Younger Dryas, when transitions to lower T-dw and delta(18)O(dw) conditions occurred. In general, millennial T-dw and delta(18)O(dw) variations recorded in MD99-2334K describe an alternation between colder, low-delta(18)O(dw) and warmer, high delta(18)O(dw) conditions, which suggests the changing local dominance of northern-sourced North Atlantic Deep Water (NADW) versus southern-sourced Antarctic Bottom Water (AABW). The observed similarity of the T-dw and GISP2 delta(18)O(ice) records would therefore suggest a common component of variability resulting from the coupling of NADW formation and Greenland climate. A link between Greenland stadials and the incursion of cold, low-delta(18)O(dw) AABW in the deep Northeast Atlantic is thus implied, which contributes to the relationship between Greenland climate and the millennial benthic delta(18)O(cc) signal since -34 cal. ka BP.
PY 2003
PD DEC
SO Geochemistry Geophysics Geosystems
SN 1525-2027
PU Amer Geophysical Union
VL 4
IS 12
UT 000187481000001
BP 1
EP 17
DI 10.1029/2003GC000585
ID 33654
ER

EF