Calcareous plankton dissolution pattern and coccolithophore assemblages during the last 600 kyr at ODP Site 1089 (Cape Basin, South Atlantic): paleoceanographic implications
Calcareous plankton dissolution pattern and coccolithophore assemblages during the last 600 kyr at ODP Site 1089 (Cape Basin, South Atlantic): paleoceanographic implications
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DOI：
10.1016/s0031-0182(03)00467-x
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发表时间：
2003-08-01
影响因子：
3
通讯作者：
Charles, CD
中科院分区：
文献类型：
--
作者：
Flores, JA;Marino, M;Charles, CD
在开普盆地南部ODP站点1089（类似于41 degreesS）的颗石藻组合被用来重建晚第四纪（海洋同位素阶段（MIS）1-15）在东南大西洋强水文梯度区的地表水条件。氧同位素地层学和钙质超微化石事件提供了地层控制，这些事件被认为在广泛的纬度范围内是同步的。最大的颗石丰度发生在冰川终止，在较小的程度上，在冰川阶段。相反，颗石藻是最不丰富的过渡期间间冰期到冰期的阶段，当碳酸钙溶解是强大的。除了这些间隔，颗石保存是中等至良好，允许研究的组合。在站点1089的颗石藻和碳酸钙的变化的总丰度的结果都从溶解和碳酸盐生产的变化。在终止，例如，最大的碳酸钙浓度发生在同一时间作为一个中等至较差的保存cocoliths和有孔虫。在这些间隔期间，碳酸盐产量相对较高。然而，在终止IV和V期间，海洋中碳酸盐产量的最大值与1089号站点的高溶解过程有关。对于终止I、II和III没有观察到这种趋势[Hodell等人，地球行星。Sci. Lett. 192（2001）109-124]。从MIS 9到13的间隔与高丰度的高度钙化的物种如Gephyrocapsa caribbeanica相一致。在这里，我们讨论了这种无处不在的物种的碳酸钙的生产和古生态意义的贡献。除了间冰期偶尔出现颗石贫瘠的间隔期外，晚更新世ODP 1089站的亚热带颗石物种一直存在。这表明，在过去的600 kyr里，极锋一直在1089号站点以南。(C)2003 Elsevier Science B. V.保留所有权利。
Coccolithophore assemblages at ODP Site 1089 in the southern Cape Basin (similar to41degreesS) were used to reconstruct surface-water conditions for the late Quaternary (Marine Isotope Stages (MIS) 1-15) in a region of strong hydrographic gradients in the southeast Atlantic. Stratigraphic control was provided by oxygen isotope stratigraphy and calcareous nannofossil events that are thought to be synchronous over a broad range of latitudes. The greatest coccolith abundances occurred at glacial terminations and, to a lesser degree, during glacial stages. Conversely, coccolithophores were the least abundant during the transition between interglacial to glacial stages, when calcium carbonate dissolution was strong. With the exception of these intervals, coccolith preservation is moderate to good, allowing study of the assemblages. The total abundance of coccolithophores and calcium carbonate variations at Site 1089 result both from variations in dissolution and carbonate production. During terminations, for example, the greatest calcium carbonate concentrations occurred at the same time as a moderate-to-poor preservation of coccoliths and foraminifers. Carbonate production was relatively high during these intervals. However, during terminations IV and V. maxima in carbonate production in the ocean were linked to high-dissolution processes at Site 1089. This trend is not observed for terminations I, II and III [Hodell et al., Earth Planet. Sci. Lett. 192 (2001) 109-124]. The interval from MIS 9 to 13 is coincident with high abundances of highly calcified species such as Gephyrocapsa caribbeanica. Here we discuss the contribution of this ubiquitous species to the production of calcium carbonate and their paleoecological significance. Except for occasional coccolith-barren intervals during interglacial periods, subtropical coccolith species were present continuously at ODP Site 1089 during the late Pleistocene. This suggests that the Polar Front has been south of Site 1089 for the last 600 kyr. (C) 2003 Elsevier Science B.V. All rights reserved.