Snow petrel stomach oil deposits (Antarctic mumiyo) as archives for the environmental history of terrestrial East Antarctica

南极地区是地球气候系统的一个重要组成部分，因为极地冰盖和周围的海洋影响着全球海平面、海洋环流和热量输送、海洋生产力和南极活动。由于东南极洲的偏远和有限的记录数量，许多问题仍然悬而未决的重要问题，南极洲的气候变化。为了建立一个完整的冰盖发展及其与气候和环境变化的联系，良好的记录和可靠的年龄控制是一个基本要求。然而，在南极洲的陆地地区，可确定年代的记录特别罕见。雪海燕（Pagodroma nivea）是南极洲特有的。这种鸟只在沿着的无冰地带和离海较远的冰原岛峰上繁殖，而它们的觅食地则位于南大洋的浮冰或开阔沃茨。在它们的筑巢地周围，为了抵御潜在的入侵者而排出的胃油不断积累并分解。这些厘米至分米厚的沉积物（称为mumiyo）的有机性质为放射性碳测年提供了难得的机会。因此，Mumiyo沉积物可以作为当地冰川历史，海平面和湖平面历史重建的档案，也提供了一个链接到海洋环境，在冰覆盖和海洋学属性。Mumiyo已被用来限制在南极洲东部不同地区的冰撤退的时间，但其作为古环境重建档案的潜力尚未得到充分利用。在拟议的项目中，我们希望系统地研究mumiyo矿床的年代学，并评估其组成的垂直变化。这将提供有关当地条件和雪海燕的古饮食变化的信息，这具有古海洋学意义。我们使用来自德龙宁毛德地不同地点的现有但尚未处理的样品材料。这也将给新的见解，在东南极冰盖的冰川消退的历史，因为晚更新世在一个地区的时间控制大多是不可用的。

The Antarctic region is an important component in the Earth climate system, since the polar ice sheets and the surrounding ocean affect global sea level, ocean circulation and heat transport, marine productivity and albedo. Due to the remoteness of East Antarctica and the limited number of records many questions remain open concerning the important issue of Antarctic climate variability. For the establishment of an Antarctic-wide picture of ice sheet development and its link to the climatic and environmental variability, good records with a robust age control are a basic requirement. However, datable records are especially rare in the terrestrial areas of Antarctica. Snow petrels (Pagodroma nivea) are endemic to Antarctica. The birds exclusively breed on un-glaciated ice-free grounds along the coast and on nunataks in farer distance to the sea while their feeding grounds are located within the pack ice or open waters of the Southern Ocean. Around their nesting sites stomach oil, which is ejected as a defence against potential intruders, accumulates and fossilizes. The organic nature of these centimetre to decimetre thick deposits (called mumiyo) provides the rare opportunity for radiocarbon dating. Mumiyo deposits can therefore serve as archives for the reconstruction of the local glacial history, sea-level, and lake-level histories, and also provide a link to the marine environment, with respect to both ice coverage and oceanographic properties. Mumiyo has been used to constrain the timing of ice retreat in different parts of East Antarctica, however its potential as an archive for paleoenvironmental reconstructions has not been fully exploited. In the proposed project we want to systematically study the chronology of mumiyo deposits and to evaluate vertical changes in their composition. This will provide information on changes in the local conditions and in the paleodiet of the snow petrels, which has paleoceanographic implications. We use existing but yet unprocessed sample material from different sites in Dronning Maud Land. This will also give new insights in the deglaciation history of the East Antarctic Ice Sheet since the late Pleistocene in a region where chronological control is mostly not available.