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

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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.