First dating of the maximum glacier extent in the Taiwanese high mountain range in the Late Pleistocene

首次测定晚更新世台湾高山冰川最大范围

• 批准号: 424056024
• 负责人: Professorin Dr. Margot Böse
• 金额: --
• 依托单位: Institut für Geographische Wissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/424056024?language=en
• 关键词: First; dating; maximum; glacier; extent

The extent and equilibrium line altitudes (ELA) of mountain glaciers are used as sensitive indictors for the climate conditions during glacial periods. Data from various Asian mountains suggest surprisingly, that the maximum glacier extent in the humid monsoonal eastern Asia was non-isochronic with the worldwide climatic last glacial maximum (LGM) and took place earlier than about 22 ka.The isolated high mountains of Taiwan represent an ideal investigation area for the timing of last glacial glacier stages in East Asia. Reaching their highest elevation at 3952 m, they are unglaciated at present, but have been subject to multiple glaciations during the Late Pleistocene and early Holocene. However, the positions of the glacier termini of the maximum glacier extent as well as the lowest ELA position are still unknown in entire Taiwan, which is due to the strong postglacial erosion and the difficult accessibility of the respective valley sections.This project applies rock surface exposure dating with in situ produced cosmogenic nuclides 10Be and 26Al to get1. time constraints of the late Pleistocene maximum valley glaciation in northern Taiwan (Hsueh Shan) and2. time constraints of cirque formation and glacial boulder transport in central Taiwan (Nengao Shan).As field mapping and sampling of boulder surfaces at an accessible terminal glacial position and of rock bars in glacial cirques were already accomplished during two campaigns in 2015 and 2016, the project focuses on the laboratory analyses for the determination of the nuclide concentrations of 14 samples, the subsequent age calculation, the data visualisation as well as a palaeoclimatic interpretation.

山地冰川的范围和平衡线高度(ELA)被用作冰期气候条件的敏感指标。令人惊讶的是，来自亚洲各山脉的数据表明，湿润的季风型东亚地区的最大冰川范围与全球气候末次冰期最大值(LGM)不是等时的，发生在约22 kb之前。台湾与世隔绝的高山是研究东亚末次冰川阶段时间的理想地区。它们的最高海拔为3952米，目前尚未冰川，但在晚更新世和全新世早期经历了多次冰川作用。然而，由于强烈的冰后侵蚀和各自山谷段的难以到达，整个台湾冰川最大范围和最低Ela的位置仍然未知。本项目采用原位产生的宇宙成因核素10Be和26Al的岩石表面暴露测年来获得1。台湾北部(雪山)晚更新世最大谷冰期的时间限制。台湾中部(嫩高山)冰环形成和冰川巨石运输的时间限制。由于在2015年和2016年的两次活动中，已经完成了对可到达的末端冰川位置的巨石表面和冰川圆圈中的岩石棒的野外测绘和采样，该项目集中于实验室分析，以确定14个样品的核素浓度，随后的年龄计算，数据可视化以及古气候解释。