Observations of δ~(13)C and Cd/Ca from benthic foraminifera have been interpreted to reflect a shoaling of northern source waters by about 1000 m during the Last Glacial Maximum, with the degree of shoaling being significant enough for the water mass to be renamed Glacial North Atlantic Intermediate Water. These nutrient tracers, however, may not solely reflect changes in water mass distributions. To quantify the distribution of Glacial North Atlantic Water, we perform a glacial water mass decomposition where the sparsity of data, geometrical constraints, and nonconservative tracer effects are taken into account, and the extrapolation for the unknown water mass end-members is guided by the modern-day circulation. Under the assumption that the glacial sources of remineralized material are similar to that of the modern day, we find a steady solution consistent with 241 δ~(13)C, 87 Cd/Ca, and 174 δ18O observations and their respective uncertainties. The water mass decomposition indicates that the core of Glacial North Atlantic Water shoals and southern source water extends in greater quantities into the abyssal North Atlantic, as previously inferred. The depth of the deep northern-southern water mass interface and the volume of North Atlantic Water, however, are not grossly different from that of the modern day. Under this scenario, the vertical structure of glacial δ~(13)C and Cd/Ca is primarily due to the greater accumulation of nutrients in lower North Atlantic Water, which may be a signal of the hoarding of excess carbon from the atmosphere by the glacial Atlantic.
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机译：底栖有孔虫的δ〜（13）C和Cd / Ca的观测结果被解释为反映了在最后一次冰期最大值期间北源水域的浅滩约1000 m，浅滩的程度足以使水量达到更名为冰河北大西洋中级水。但是，这些营养物示踪剂可能不仅仅反映水质分布的变化。为了量化北大西洋冰川水的分布，我们进行了冰川水质量分解，其中考虑了数据的稀疏性，几何约束和非保守示踪作用，并且未知水质量末端成员的外推由现代流通。在假定矿化物质的冰川来源与现代相似的前提下，我们找到了与241δ〜（13）C，87 Cd / Ca和174δ18O观测值及其各自不确定性相一致的稳定解。水质的分解表明，如先前推断的那样，冰川北大西洋水浅滩和南部水源的核心大量进入深海北部大西洋。北-南深水质界面的深度和北大西洋水的体积与现代没有太大差异。在这种情况下，冰川δ〜（13）C和Cd / Ca的垂直结构主要是由于北大西洋下部水域中养分的积累更多，这可能是冰山从大气中ho积过量碳的信号。冰河大西洋。
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