Aragonite preservation in late Quaternary sediment cores on the Brazilian Continental Slope: implications for intermediate water circulation
Aragonite preservation in late Quaternary sediment cores on the Brazilian Continental Slope: implications for intermediate water circulation
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DOI：
10.1007/s005310050291
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发表时间：
2000-03
影响因子：
2.3
通讯作者：
S. Gerhardt;H. Groth;C. Rühlemann;R. Henrich
中科院分区：
文献类型：
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作者：
S. Gerhardt;H. Groth;C. Rühlemann;R. Henrich
我们提出了晚第四纪记录的文石保存确定的巴西大陆斜坡（1790-2585米水深），北大西洋深水（NADW）目前占主导地位的沉积岩芯。我们已经使用了各种间接溶解代理（碳酸盐含量，文石/方解石含量和砂的百分比），以及腹足丰度和破碎的Limacina inflatato确定文石保存的状态。此外，溶出敏感性的三个Limacinaspecies的显微镜调查得出LimacinaDissolution指数，以及与大多数其他代理。文石保存良好，发现在全新世部分，而文石溶解逐渐增加向下钻。这种一般模式是由于孔隙沃茨的文石腐蚀性的总体增加。叠加在这一早期成岩趋势是高频波动的文石保存，这可能与气候引起的变化的中间水团。
We present late Quaternary records of aragonite preservation determined for sediment cores recovered on the Brazilian Continental Slope (1790–2585 m water depth) where North Atlantic Deep Water (NADW) dominates at present. We have used various indirect dissolution proxies (carbonate content, aragonite/calcite contents, and sand percentages) as well as gastropodal abundances and fragmentation ofLimacina inflatato determine the state of aragonite preservation. In addition, microscopic investigations of the dissolution susceptibility of threeLimacinaspecies yielded theLimacinaDissolution Index which correlates well with most of the other proxies. Excellent preservation of aragonite was found in the Holocene section, whereas aragonite dissolution gradually increases downcore. This general pattern is attributed to an overall increase in aragonite corrosiveness of pore waters. Overprinted on this early diagenetic trend are high-frequency fluctuations of aragonite preservation, which may be related to climatically induced variations of intermediate water masses.