Reappraisal of sea-level lowstand during the Last Glacial Maximum observed in the Bonaparte Gulf sediments, northwestern Australia
Reappraisal of sea-level lowstand during the Last Glacial Maximum observed in the Bonaparte Gulf sediments, northwestern Australia
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重新评估在澳大利亚西北部波拿巴湾沉积物中观察到的末次盛冰期海平面低位
DOI：
10.1016/j.quaint.2015.03.032
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发表时间：
2016
影响因子：
2.2
通讯作者：
Julien Bourget and Hiroyuki Matsuzaki
中科院分区：
文献类型：
--
作者：
Takeshige Ishiwa;Yusuke Yokoyama;Yosuke Miyairi;Stephen Obrochta;Takenori Sasaki;Akihisa Kitamura;Atsushi Suzuki;Minoru Ikehara;Ken Ikehara;Katsunori Kimoto;Julien Bourget and Hiroyuki Matsuzaki
在末次盛冰期（LGM），冰量达到相对最大值，全球气温低于今天。了解大陆冰量变化需要精确重建相对海平面，但构造抬升和均衡调整效应使许多记录复杂化。利用海洋沉积物岩心从波拿巴湾在澳大利亚西北部，一个所谓的“远场”构造稳定的网站，横山等人。（2000）报道LGM在19 ka突然终止，海平面迅速上升（19 ka事件）。他们的海平面重建确定了末次盛冰期终止的年龄，但其开始的时间仍然没有那么好的限制，部分原因是放射性碳分析的数量不足以澄清末次盛冰期的持续时间。在这里，我们回到波拿巴湾，并提出了一个新的相对海平面，更好地约束末次大冰期的持续时间与高分辨率放射性碳测年最近恢复的海洋沉积物芯（水深：120米，长度：583厘米）。放射性碳测年的23个软体动物和26个散装有机质样品，连同总有机碳，总氮和稳定的碳同位素，提供了一个记录的古环境的变化响应海平面的变化。我们的研究结果表明，LGM海平面最低发生在20.8 cal ka BP和LGM的持续时间比以前报道的短。
During the Last Glacial Maximum (LGM), ice volume reached a relative maximum and global temperature was lower than today. Understanding continental ice volume change requires accurate reconstruction of relative sea level, but tectonic uplift and isostatic adjustment effects complicate many records. Using marine sediment cores from the Bonaparte Gulf in northwestern Australia, a so-called “far field” tectonically stable site, Yokoyama et al. (2000) reported that the LGM terminated abruptly at 19 ka with a rapid sea-level rise (19 ka event). Their sea-level reconstruction determined the age of the LGM termination, but the timing of its inception remained less well constrained, partly because the number of radiocarbon analyses was insufficient to clarify LGM duration. Here we return to the Bonaparte Gulf and present a new relative sea level that better constrains LGM duration with high-resolution radiocarbon dating of a recently recovered marine sediment core (water depth: 120 m, length: 583 cm). Radiocarbon dating of 23 molluscs and 26 bulk organic-matter samples, together with total organic carbon, total nitrogen, and stable carbon isotopes, provide a record of paleoenvironmental variability in response to sea level change. Our results indicate that the LGM sea-level minimum occurred at 20.8 cal ka BP and the LGM duration was shorter than previously reported.