Evaluation of Mumiyo Deposits From East Antarctica as Archives for the Late Quaternary Environmental and Climatic History
Evaluation of Mumiyo Deposits From East Antarctica as Archives for the Late Quaternary Environmental and Climatic History
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DOI：
10.1029/2018gc008054
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发表时间：
2019-01-01
影响因子：
3.5
通讯作者：
Kuhn, G.
中科院分区：
文献类型：
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作者：
Berg, S.;Melles, M.;Kuhn, G.
Mumiyo沉积物形成于雪海燕（Pagodroma nivea）筑巢地附近，由化石胃油（Mumiyo）、鸟粪和成矿物质组成。在此，我们评价了来自中部Dronning Maud地内陆山脉的mumiyo沉积物作为南极洲古环境重建的高分辨率档案。内部构造和化学成分的研究表明，尽管矿床的外部形态不规则，但层压反映了渐进沉积。详细的放射性碳分析表明，地层是完整的：C-14年龄在沉积物中逐渐变小。对8个木乃伊沉积物样品的脂肪酸和正醇组成进行了测定。低分子量化合物（C-14至C-18）的优势指向饮食信号；然而，与新鲜胃油相比，不饱和化合物的比例相对较低，表明存在沉积后降解。我们在mumiyo中发现了海洋硅藻，这可能为海燕觅食栖息地的海冰状况提供了一个代表。调查沉积物的年龄范围表明，雪海燕在17 ka至50 ~ 58 ka之间占据了所分析的地点。与晚期海洋同位素阶段3和末次盛冰期相比，沉积速率的变化表明，在46 - 42 ka期间，Petermann范围内的沉积频率更高。
Mumiyo deposits form in the vicinity of snow petrel (Pagodroma nivea) nesting sites and consist of fossil stomach oil (mumiyo), guano, and minerogenic material. Here we evaluate mumiyo deposits from the inland mountain ranges of central Dronning Maud Land as high-resolution archives for paleoenvironmental reconstructions in Antarctica. Investigation of internal structures and chemical composition shows that the lamination reflects progressive sedimentation, despite the irregular outer morphology of the deposits. Detailed radiocarbon analysis demonstrates that stratigraphies are intact: C-14 ages become successively younger upwards in the deposits. Fatty acid and n-alcohol composition was determined on samples from eight mumiyo deposits. Dominance of low molecular weight compounds (C-14 to C-18) points to a dietary signal; however, the relatively low proportions of unsaturated compounds compared to fresh stomach oils indicates some postdepositional degradation. We found marine diatoms in the mumiyo, which potentially provide a proxy for sea ice conditions in the foraging habitat of the petrels. Age ranges of the investigated deposits suggest occupation of the analyzed sites by snow petrels from 17 ka to > 58 ka. Changes in deposition rates point to higher occupation frequency in Petermann Range from 46 to 42 ka compared to the late marine isotope stage 3 and the Last Glacial Maximum.