Late Quaternary iceberg-rafted detritus events on the Denmark Strait Southeast Greenland continental slope (∼65°N):: Related to north Atlantic Heinrich events?
Late Quaternary iceberg-rafted detritus events on the Denmark Strait Southeast Greenland continental slope (∼65°N):: Related to north Atlantic Heinrich events?
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DOI：
10.1016/s0025-3227(98)00029-2
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发表时间：
1998-08-01
期刊：
影响因子：
2.9
通讯作者：
Erlenkeuser, H
中科院分区：
文献类型：
--
作者：
Andrews, JT;Cooper, TA;Erlenkeuser, H
HU93030-007 LCF（北纬 65 度 01.39'，西经 30 度 14.81'）是一个长 4.5 m 的巨型（直径 11 cm）活塞芯，位于丹麦海峡基台以南大陆坡水深 1800 m 处。岩芯在康克鲁斯瓦克海槽下方的一个地点采集了声学分层沉积物样本。浮游有孔虫的 9 个 AMS C-14 年代表明，核心跨度类似于 14 至 28 C-14 ka。沉积物由两种主要岩相组成：岩相 I (LI) 包括棕褐色/赭石层段，富含大于 2 毫米的冰筏砂岩/粉砂岩碎屑，平均厚度为 47 厘米；它还与碳酸盐含量和 TOC% 的峰值有关。岩相 II (LII) 由细粒、深灰色、半远洋沉积物组成。 LI 存在三个不同的区间，其日期分别为 14.3 至 15.5 (LIc)、20.1 至 21.9 (LIb)、24.7 至 25.8 (LIa) ka。这些年龄表明 LI 的沉积大约与北大西洋海因里希事件 1 和 2 同时发生，而 LIa 似乎比 H-3 更年轻。岩相 I 源自未知来源的遥远冰河，但并非来自劳伦泰德冰盖东北部。 Neogloboquadrina pachyderma sinistral 的稳定同位素研究显示，几乎没有证据表明与 LI 相关的重大融水事件，但令人惊讶的是，在底栖有孔虫分析（Cibicidoides wuellerstorfi 和 Melonis zaandamae）中存在轻氧同位素事件。 HU93030-007 冰山漂流碎屑 (IRD) 事件的年龄与东格陵兰斜坡丹麦海峡以北核心的 IRD 峰值相似。 HU87033-009 LCF（SE Baffin 坡度，北纬 62 度 30.99'，西经 59 度 26.82'，西经 1437 米）与 HU93030-007 的位置相似，但相对于劳伦泰冰盖；其在浮游有孔虫上的 delta(18)O 记录实际上与 HU93030-007 相同。在这两个核心中，IRD 事件的时间在 14 到 30 ka 之间是相似的。 H-3 可能作为 IRD 事件存在于 HU87033-009 中，但与 H-1 和 H-2 相比，它作为可辨别的碎屑碳酸盐事件并不明显。 (C) 1998 Elsevier Science B.V. 保留所有权利。
HU93030-007 LCF (65 degrees 01.39'N and 30 degrees 14.81'W) is a 4.5 m long, giant (11 cm diameter) piston core from 1800 m water depth on the continental slope, south of the Denmark Strait sill. The core sampled acoustically stratified sediments at a site below the Kangerlussuaq Trough. Nine AMS C-14 dates on planktic foraminifera indicate that the core spans similar to 14 to 28 C-14 ka. The sediments consists of two principal lithofacies: Lithofacies I (LI) comprises tan/ochre intervals with abundant ice-rafted sandstone/siltstone clasts larger than 2 mm and with an average thickness of 47 cm; it is also associated with peaks in carbonate content and TOC%. Lithofacies II (LII) consists of fine-grained, dark gray, hemipelagic sediment. There are three distinct intervals of LI dated between 14.3 and 15.5 (LIc), 20.1 and 21.9 (LIb), 24.7 and 25.8 (LIa) ka. The ages suggest that deposition of LI is approximately coeval with Heinrich events 1 and 2 in the North Atlantic, whereas LIa appears younger than H-3. Lithofacies I is derived from far-travelled ice begs from an unknown source, but not from the northeastern Laurentide Ice Sheet. Stable isotope studies on Neogloboquadrina pachyderma sinistral show little evidence for significant meltwater events associated with LI, but surprisingly, light oxygen isotopic events are present in the benthic foraminiferal analyses (Cibicidoides wuellerstorfi and Melonis zaandamae). The ages of the HU93030-007 iceberg-rafted detritus (IRD) events are similar to IRD peaks in cores north of Denmark Strait, on the East Greenland slope. HU87033-009 LCF (SE Baffin slope, 62 degrees 30.99'N and 59 degrees 26.82'W, 1437 m wd) is situated in a similar position to HU93030-007 but with respect to the Laurentide Ice Sheet; its delta(18)O record on planktic foraminifera is virtually identical to that of HU93030-007. The timing of IRD events is similar in both these cores between 14 and 30 ka. H-3 may be present in HU87033-009 as an IRD event, but in contrast to H-1 and H-2, it is not evident as a discernible detrital carbonate event. (C) 1998 Elsevier Science B.V. All rights reserved.