SGER: Southern Andes Glacial Chronology: Test of Abrupt Global Climate Change

SGER：安第斯山脉南部冰川年代学：全球气候突变的检验

• 批准号: 9020736
• 负责人: George Denton
• 金额: $ 2.73万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-02-15 至 1992-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9020736&HistoricalAwards=false
• 关键词: SGER; Southern; Andes; Glacial; Chronology

What drives glacial climate cycles? This fundamental question lies at the heart of understanding global changes of recent ice ages. The PI and others have suggested that abrupt reorganizations of the ocean-atmosphere system are the key events linking orbital perturbations to global ice-age climate changes. This hypothesis has fundamental implication about understanding past climate changes as well as anticipating changes in the earth's present climate. It is suggested that major ocean and atmospheric changes begin abruptly and synchronously on a global scale during major climate transitions. To test such a prediction the PI proposes to compare detailed paleoclimatic records of glacier margins and equilibrium-line altitudes (which are sensitive indicators of atmospheric temperature changes) at mid latitudes in both polar hemispheres through the last glacial-interglacial transition. For this test, he seeks a precise Southern Hemisphere alpine glacier record. This is a grant to support obtaining the necessary glacial record while avoiding the inherent and time-consuming gamble of mapping a moraine sequence and coming up empty for radiocarbon age control. Most projects on alpine glaciation have not been particularly helpful because of lack of radiocarbon dates. After examining Southern Hemisphere alpine areas in New Zealand and South America, the PI proposes reconnaissance field work in southern Chile in the area covered by a former alpine glacier system that extended form the crest of the Andes westward to Chile Island. This field work will involve reconnaissance mapping multiple moraines and outwash bodies of Llanquihue (late Wisconsin/marine isotope stage 2) age on Chiloe Island and the adjacent mainland. Existing radiocarbon sites will be tied into this map and abundant new stratigraphic sites with organic material will be examined and dated to determine if they can yield additional chronologic control. Pollen and spore stratigraphy will be examined for intertill peats. Finally, the PI will determine if minimum ages for ice recession deep into the mountains can be obtained from basal dates in lakes and bogs. The resulting preliminary chronology will clarify whether this region of the Southern Andes is capable of producing a paleoclimatic record with the detailed age control necessary to test the hypothesis of abrupt ocean-atmosphere reorganizations. Hence, the feasibility of a long-term study in the southern Andes will emerge from this preliminary chronology. This work is supported by a Small Grant for Exploratory Research and is important because it seeks to understand climate changes on time scales relevant to human activities.

是什么推动了冰川气候的循环？ 这一根本 问题在于理解全球变化的核心， 最近的冰河时代 PI和其他人表示，突然 海洋-大气系统的重组是 将轨道扰动与全球冰期气候联系起来的事件 变化 这一假设有着基本的含义， 了解过去的气候变化， 地球目前气候的变化。 建议在 主要的海洋和大气变化开始突然， 在全球范围内同步进行。 为了测试这种预测，PI建议比较详细的 冰川边缘和平衡线的古气候记录 高度（这是大气的敏感指标） 温度变化）在两极半球中纬度地区 经历了最后一次冰期-间冰期的转变。 在这个测试中， 他在寻找南半球高山冰川的精确记录。 这是一个赠款，以支持获得必要的冰川 记录，同时避免固有的和耗时的赌博， 绘制了一个冰碛序列， 年龄控制。 大多数关于高山冰川作用的项目 因为缺乏放射性碳年代测定，所以特别有用。 后 考察新西兰南半球的高山地区， 南美洲，PI建议在 智利南部，位于前高山冰川覆盖的地区 从安第斯山脉向西延伸到 智利岛。 这项实地工作将包括侦察 绘制了Llanquihue（晚期）的多个冰碛和冰水沉积体 奇洛埃岛的威斯康星州/海洋同位素阶段2）年龄和 毗邻大陆。 现有的放射性碳站点将被绑定到 这张地图和丰富的新的地层网站与有机 材料将被检查和日期，以确定他们是否可以 产生额外的时序控制。 孢粉 将对层位进行检查，以确定是否有耕层间泥炭。 最后 PI将确定冰衰退的最小年龄是否深入到 山脉可以从湖泊和沼泽的基部日期中获得。 由此产生的初步年表将澄清这是否 南安第斯山脉地区能够产生 古气候记录与详细的年龄控制， 检验海洋-大气突然重组的假设。 因此，在南安第斯山脉进行长期研究的可行性 将从这份初步的年表中显现出来 这项工作得到了探索性研究的小额资助。 研究是重要的，因为它试图了解气候 与人类活动相关的时间尺度上的变化。