Collaborative Research: Developing an Improved Chronology of the Southern Margin of the Scandinavian Ice Sheet

这是一个合作项目，其主要目标是编制一个改进的末次冰期斯堪的纳维亚冰盖（SIS）南部（陆地）边缘年表，以便将这一边缘的历史与斯堪的纳维亚冰盖西部边缘的历史、与其他冰盖的历史以及与其他气候变化记录进行比较，从而进一步评估冰缘波动与气候变化之间的关系。该项目将通过(1)AMS放射性碳测年和(2)宇宙成因核素（10Be和26Al）测定冰碛表面不稳定巨石的年代来构建年表。突出的退潮冰碛在距今约18000年的晚期魏奇塞尔最大值之后划分了5至6个后退阶段，清楚地表明了一个强烈的千年尺度信号（距今18000年至10000年之间有5至6次冰碛形成事件）。然而，对SIS南缘退陷期的年代控制却十分缺乏。该项目将调查(i)南SIS边缘移动到末次最大冰期位置之前的非冰期间隔的年龄，（ii）南缘达到末次最大冰期的年龄，以及（iii）由退潮冰碛显著记录的南缘退潮期的面积。该项目将重点研究位于波兰、拉脱维亚、爱沙尼亚、立陶宛、白俄罗斯和俄罗斯的SIS矿床和地貌。

This is a collaborative project whose principal objective is to develop an improved chronology of the southern (terrestrial) margin of the Scandinavian Ice Sheet (SIS) during the last glaciation in order to compare the history of this margin with that of the western margin of the SIS, with other ice sheets, and with other records of climate change in order to further evaluate the relationship between ice-margin fluctuations and climate change. The project will construct a chronology by dating (1) key organic-bearing units by AMS radiocarbon and (2) erratic boulders on moraine surfaces using cosmogenic nuclides (10Be and 26Al). Prominent recessional moraines delimit five to six retreat phases following the late Weichselian maximum at about 18,000 yr B.P., clearly suggesting a strong millennial-scale signal (five to six moraine building events between 18,000 and 10,000 yr B.P). However, dating control constraining the age of retreat phases along the southern SIS margin is all but lacking. The project will investigate (i) the age of the nonglacial interval before advance of the southern SIS margin to its last glacial maximum position, (ii) the age that the southern margin reached its last glacial maximum, and (iii) the area(s) of recessional phases of the southern margin that are prominently recorded by recessional moraines. The project will focus on deposits and landforms of the SIS in Poland, Latvia, Estonia, Lithuania, Belarus, and Russia.