FN Archimer Export Format
PT J
TI New spatial Mg/Ca-temperature calibrations for three Arctic, benthic foraminifera and reconstruction of north Iceland shelf temperature for the past 4000 years
BT 
AF KRISTJANSDOTTIR, G. B.
   LEA, D. W.
   JENNINGS, A. E.
   PAK, D. K.
   BELANGER, C.
AS 1:1,2;2:3,4;3:1,2;4:3,4;5:3,4;
FF 1:;2:;3:;4:;5:;
C1 Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA.
   Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA.
   Univ Calif Santa Barbara, Dept Earth Sci, Santa Barbara, CA 93106 USA.
   Univ Calif Santa Barbara, Inst Marine Sci, Santa Barbara, CA 93106 USA.
C2 UNIV COLORADO, USA
   UNIV COLORADO, USA
   UNIV CALIF SANTA BARBARA, USA
   UNIV CALIF SANTA BARBARA, USA
IF 2.354
TC 40
UR https://archimer.ifremer.fr/doc/00238/34935/33256.pdf
LA English
DT Article
CR IMAGES V LEG 1-MD114
   IMAGES V LEG 4-MD114
BO Marion Dufresne
DE ;Mg/Ca;benthic foraminifera;temperature calibrations;Arctic;shelf environment;Iceland shelf
AB We have developed cold-end Mg/Ca-temperature calibrations for three common Arctic benthic foraminifera, Islandiella norcrossi/helenae, Melonis barleeanus, and Cassidulina neoteretis, and compare the three calibrations in a late Holocene downcore record (0-4000 cal yr B.P.). The calibration and downcore trends for the three Arctic species extend the observation that Mg incorporation into benthic foraminifera is species specific. For the calibration we use a set of CTD casts, bottom water delta(18)O(seawater) measurements, and surface grab-samples collected from the Iceland margin (cruise B997) and the Greenland margin (cruise BS1191). Water depth of sites used ranges from 165 to 656 m, while spatial bottom temperature ranges from 0 to 7 degrees C. Mg/Ca values ranged from 1.02 to 1.47 for I. norcrossi/helenae, 0.64 to 2.21 for M. barleeanus, and 0.93 to 1.38 mmol/mol for C. neoteretis. We calibrated Mg/Ca content against isotopic calcification temperature (calculated using T = 16.9 - 4.0*(delta(18)O(calcite) (corrected for vital effect) - delta(18)O(seawater))). Exponential calibrations for the three species are as follows: I. norcrossi/helenae Mg/Ca = 1.051 +/- 0.03 * exp(0.060 +/- 0.011 * T), M. barleeanus Mg/Ca = 0.658 +/- 0.07 * exp(0.137 +/- 0.020 * T), and C. neoteretis Mg/Ca = 0.864 +/- 0.07 * exp(0.082 +/- 0.020 * T). On the basis of Mg/Ca in these benthic species the downcore record from core MD99-2269 is reconstructed. Bottom temperature values are interpreted to reflect variable inflow of Atlantic and Arctic water to the north Iceland shelf during the last 4000 cal yr B. P. All three reconstructions show a decline by 0.1 degrees C per century from circa 1500-0 cal yr B.P., which coincides with an increase in Arctic benthic foraminifera abundances and a rise in sea ice proxies in the same core. Intriguingly, C. neoteretis diverges periodically to higher average temperature (Atlantic water conditions) than shown by M. barleeanus or I. norcrossi/helenae (which both show Arctic water temperature) circa 1500-4000 cal yr B.P.
PY 2007
PD MAR
SO Geochemistry Geophysics Geosystems
SN 1525-2027
PU Amer Geophysical Union
VL 8
IS 3
UT 000245014800001
BP 1
EP 27
DI 10.1029/2006GC001425
ID 34935
ER

EF