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

冰川气候循环的驱动因素是什么？这个基本问题是理解最近冰河时代全球变化的核心。PI和其他人认为，海洋-大气系统的突然重组是将轨道扰动与全球冰期气候变化联系起来的关键事件。这一假设对于理解过去的气候变化以及预测地球现在的气候变化具有基本的意义。研究表明，在全球范围内，海洋和大气的重大变化是在重大气候过渡期间突然而同步开始的。为了验证这一预测，国际气候研究所建议比较两个极地半球中纬度冰川边缘和平衡线高度(这是大气温度变化的敏感指标)在最后一次冰川-间冰期过渡期间的详细古气候记录。对于这项测试，他寻求南半球阿尔卑斯山冰川的精确记录。这是一笔赠款，用于支持获得必要的冰川记录，同时避免固有的、耗时的赌博，即绘制冰川序列图，并在放射性碳年龄控制方面一无所获。由于缺乏放射性碳年代，大多数关于高山冰川的项目都没有特别的帮助。在考察了新西兰和南美洲的南半球高山地区后，PI建议在智利南部的侦察现场工作，该地区由前高山冰川系统覆盖，该冰川系统从安第斯山脉向西延伸到智利岛。这项实地工作将包括对奇洛岛和邻近大陆上的Llanquihue(威斯康星州晚期/海洋同位素阶段2)年龄的多个冰雹和陆壳进行勘察测绘。现有的放射性碳化物遗址将被纳入这张地图，并将对大量具有有机物质的新地层遗址进行检查和年代测定，以确定它们是否可以产生额外的年代学控制。将对花粉和孢子地层学进行检查，以寻找间作泥炭。最后，PI将确定是否可以从湖泊和沼泽的基本日期获得深山冰川消退的最小年龄。由此产生的初步年表将澄清这一南安第斯山脉地区是否能够产生具有详细年龄控制的古气候记录，以检验海洋-大气突然重组的假说。因此，在南安第斯山脉进行长期研究的可行性将从这一初步年表中浮现出来。这项工作得到了探索性研究小额赠款的支持，之所以重要，是因为它试图了解与人类活动相关的时间尺度上的气候变化。

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.