Holocene history of the Larsen-A Ice Shelf constrained by geomagnetic paleointensity dating
Holocene history of the Larsen-A Ice Shelf constrained by geomagnetic paleointensity dating
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受地磁古强度测年约束的拉森-A冰架全新世历史
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
L. Eglinton
中科院分区：
文献类型：
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作者：
S. Brachfeld;E. Domack;C. Kissel;C. Laj;A. Leventer;S. Ishman;R. Gilbert;A. Camerlenghi;L. Eglinton
从原拉尔森-A冰架下收集的沉积记录揭示了拉尔森-A地区的全新世历史。这一记录开始于10.7 60.5 ka从地面冰到漂浮冰架的转变，结束于现代的衰退。该记录包含了几个晚全新世的泥质软泥层，表明接近于多产的开放水域事件。从这些沉积物中获得的放射性碳年龄由于碎屑和再加工碳的存在而变得复杂。我们排除了这些复杂的因素，并利用参考曲线对地磁场古强度记录进行校正，建立了Larsen-A冰架历史的年代学。这种方法为缺乏放射性碳定年材料的沉积物序列提供了时间控制。可以识别波长为2 ~ 3 k.y的地磁古强度特征，并进行半球间对比，说明了利用地磁古强度变化作为亚米兰科维奇时间尺度的全球对比和测年工具的潜力。
A sedimentary record collected from beneath the former Lar- sen-A Ice Shelf reveals the Holocene history of the Larsen-A re- gion. The record begins with the transition from grounded ice to a floating ice shelf, completed by 10.7 6 0.5 ka, and ends with the modern recession. The record contains several late Holocene dia- tomaceous ooze layers that suggest proximity to productive open- water events. Radiocarbon ages obtained from these sediments were complicated by the presence of detrital and reworked carbon. We have eliminated these complications and constructed a chro- nology for the Larsen-A Ice Shelf history via tuning of the geo- magnetic field paleointensity record with a reference curve. This approach provides chronological control to sediment sequences that lack appropriate material for radiocarbon dating. Geomag- netic paleointensity features with wavelengths of 2-3 k.y. can be recognized and interhemispherically correlated, illustrating the po- tential to use geomagnetic paleointensity variations as a global cor- relation and dating tool at sub-Milankovitch time scales.