Benthic Isotope Evidence for Changes of the Mediterranean Outflow During the Late Quaternary
Benthic Isotope Evidence for Changes of the Mediterranean Outflow During the Late Quaternary
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晚第四纪地中海流出量变化的底栖同位素证据
DOI：
10.1029/pa002i006p00543
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
H. Erlenkeuser
中科院分区：
文献类型：
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作者：
R. Zahn;M. Sarnthein;H. Erlenkeuser
对直布罗陀附近及其以南（12°-36 ° N，水深500-2800 m）的一套沉积物岩心进行了底栖有孔虫Cibicidoides wuellerstorfi和Planulina ariminensis的稳定同位素分析。在盛冰期，数据显示直布罗陀海峡（36°N）附近中等深度的δ 13 C值较高，高达1.6‰。我们的数据证明，这些值向南减小，但38°N以北的中等深度岩心数据显示，这些值向北减小（Duplessy等人[1987]）。因此，δ 13 C的分布格局提供了重要的证据，营养耗尽的地中海外流水（MOW）的影响，冰川东北大西洋水文。在氧同位素终止I和II期间，碳同位素梯度指示显著降低但仍然活跃的MOW。根据δ 18 O的波动推断，大西洋MOW的温度在冰期时要低5°C。在冰期和终端I期间，MOW的最大δ 13 C值与北大西洋深层水（NADW）的最小值相关，反之亦然。这两个水团的碳同位素信号的气候变化的逆响应表明，盐MOW北大西洋的供应可能是不太重要的NADW的形成比以前假设的。
A suit of sediment cores close to and south of the Strait of Gibraltar (12°-36°N, 500–2800 m water depth) were analyzed for stable isotopes in epibenthic foraminifers Cibicidoides wuellerstorfi and Planulina ariminensis. During peak glacial times, the data exhibit higher δ13C values of up to 1.6‰ at intermediate depths near the Strait of Gibraltar (36°N). The values decrease to the south as evidenced by our data, but also to the north as revealed by data of intermediate depth cores north of 38°N (in Duplessy et al. [1987]). Thus, the distribution pattern of δ13C provides crucial evidence for an increased influence of nutrient depleted Mediterranean Outflow Water (MOW) on the glacial northeast Atlantic hydrography. During oxygen isotope Terminations I and II, the meridional carbon isotope gradient indicates a significantly decreased but still active MOW. As deduced from the δ18O fluctuations, the temperatures of the MOW in the Atlantic were lower during glacial times by as much as 5°C. During glacial times and during Termination I the maximum δ13C values of the MOW correlate with minimum values of the North Atlantic Deep Water (NADW) and vice versa. This inverse response to climatic change of the carbon isotope signals of both water masses indicates, that the supply of saline MOW to the north Atlantic may be less important for the formation of NADW than previously assumed.