Present and former equilibrium line altitudes in the Taiwanese high mountain range

Abstract

Previously reported values of former equilibrium line altitudes (ELA) for Taiwan are based on sparse field data or extrapolations from Japan or China. This paper presents new calculations based on recently obtained geological data (Hebenstreit, R, Böse, M, 2003. Geomorphological evidence for a Late Pleistocene glaciation in the high mountains of Taiwan dated with age estimates by optically stimulated luminescence (OSL). Zeitschrift für Geomorphologie N.F. Suppl.-Bd.130, 31–49; Hebenstreit, R., Murray, A.S., Böse, M., this vol. Late Pleistocene and Early Holocene glaciations in Taiwanese mountains. Quaternary International) from three Taiwanese mountain massifs ( Nanhuta Shan, Hsueh Shan and Yushan) using established calculation methods (Benn, D.I., Lehmkuhl, F., 2000. Mass balance and equilibrium-line altitudes of glaciers in high-mountain environments. Quaternary International 65–66, 15–29; Porter, S.C., 2001. Snowline depression in the tropics during the Last Glaciation. Quaternary Science Reviews 20(10), 1067–1091). The relationship of annual precipitation and summer (JJA) temperature (Ohmura, A., Kasser, P., Funk, M., 1992. Climate at the equilibrium line of glaciers. Journal of Glaciology 38(130), 397–411) obtained from a 30 year meteorological database is used to estimate the present theoretical (virtual) equilibrium line altitude (ELA t) at about 4000 m over the southern and 3900 m over the northern part of Taiwan. The ELA was 3350–3500 m during Late Glacial to Early Holocene time (11–8 ka). Including a minimum post-glacial mountain uplift rate of 5 mm/a (Lundberg, N., Dorsey, R.J., 1990. Rapid Quaternary emergence, uplift, and denudation of the Coastal Range, eastern Taiwan. Geology 18(7), 638–641); Lin, C.-H., 1998. Tectonic implications of an aseismic belt beneath the eastern central range of Taiwan: crustal subduction and exhumation. Journal of the Geological Society of China 41(3), 441–460) in the calculation, the ELA depression (ΔELA) was 400–550 m during this period. Data from LGM or earlier are still rare, but glacial landforms and deposits indicate the ELA position at 2775–3195 m and the ΔELA of 705–1125 m.