BIOGENIC OPAL IN SOUTHERN OCEAN SEDIMENTS OVER THE LAST 450,000 YEARS: IMPLICATIONS FOR SURFACE WATER CHEMISTRY AND CIRCULATION

被引:157
作者
Charles, Christopher D. [1 ,2 ]
Froelich, Philip N. [1 ,2 ]
Zibello, Michaeal A. [1 ,2 ]
Mortlock, Richard A. [1 ]
Morley, Joseph J. [1 ]
机构
[1] Columbia Univ, Lamont Doherty Geol Observ, Palisades, NY 10964 USA
[2] Columbia Univ, Dept Geol Sci, New York, NY 10027 USA
来源
PALEOCEANOGRAPHY | 1991年 / 6卷 / 06期
关键词
D O I
10.1029/91PA02477
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
We present records of biogenic opal percentage and burial rate in 12 piston cores from the Atlantic and Indian sectors of the Southern Ocean. These records provide a detailed, quantitative description of changing patterns of opal deposition over the last 450 kyr. The striking regional coherence of these records suggests that dissolution in the deep sea and sediment pore waters does not obscure the surface productivity signal, and therefore these opal time series can be used in combination with other surface water tracers to make inferences about the chemistry and circulation of the Southern Ocean under different global climate conditions. Three broad depositional patterns can be distinguished. Northernmost records (39 degrees-42 degrees S latitude) are characterized by enhanced opal burial during glacial periods and strong 41 kyr periodicity. Records from cores just north of the present Antarctic Polar Front (46 degrees-49 degrees S) show even larger increases in opal burial rate during glacial intervals, but have variance concentrated in the 100 and 23 kyr bands. Southern most records (51 degrees-55 degrees S) are completely out of phase with those to the north, with greatly reduced opal burial rates during glacial periods. Taken as a whole, the opal records show no evidence for the increased total Antarctic productivity predicted by recent geochemical models of atmospheric CO2 variability. T he areal expansion of Southern Ocean sea ice over the present zone of high siliceous productivity provides one plausible explanation for the glacial-interglacial opal patterns. The excess silica not taken up in this zone during glacial periods would contribute to greater nutrient availability and thus higher productivity in the subantarctic region. However, local circulation changes may act to modify this basic signal, possibly accounting for the observed differences in the opal variance spectra.
引用
收藏
页码:697 / 728
页数:32
相关论文
共 63 条
[1]   CALIBRATION OF THE C-14 TIMESCALE OVER THE PAST 30,000 YEARS USING MASS-SPECTROMETRIC U-TH AGES FROM BARBADOS CORALS [J].
BARD, E ;
HAMELIN, B ;
FAIRBANKS, RG ;
ZINDLER, A .
NATURE, 1990, 345 (6274) :405-410
[2]  
BERGER AL, 1978, J ATMOS SCI, V35, P2362, DOI [10.1175/1520-0469(1978)035<2362:LTVODI>2.0.CO
[3]  
2, 10.1016/0033-5894(78)90064-9]
[4]   THE ROLE OF VERTICAL CHEMICAL FRACTIONATION IN CONTROLLING LATE QUATERNARY ATMOSPHERIC CARBON-DIOXIDE [J].
BOYLE, EA .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1988, 93 (C12) :15701-15714
[5]  
Broecker W.S., 1982, TRACERS SEA, P690
[6]   THE CAUSE OF THE GLACIAL TO INTERGLACIAL ATMOSPHERIC CO2 CHANGE: A POLAR ALKALINITY HYPOTHESIS [J].
Broecker, Wallace S. ;
Peng, Tsung-Hung .
GLOBAL BIOGEOCHEMICAL CYCLES, 1989, 3 (03) :215-239
[7]   REVISED ESTIMATE FOR THE RADIOCARBON AGE OF NORTH-ATLANTIC DEEP-WATER [J].
BROECKER, WS .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AND ATMOSPHERES, 1979, 84 (NC6) :3218-3226
[8]   REAPPRAISAL OF SEA-ICE DISTRIBUTION IN ATLANTIC AND PACIFIC SECTORS OF THE SOUTHERN-OCEAN AT 18,000 YR BP [J].
BURCKLE, LH ;
ROBINSON, D ;
COOKE, D .
NATURE, 1982, 299 (5882) :435-437
[9]  
BURCKLE LH, 1978, GEOLOGY, V6, P243, DOI 10.1130/0091-7613(1978)6<243:ILDLOT>2.0.CO
[10]  
2