[M-IS03] Developments and applications of XRF-core scanning techniques in natural archives

[MIS03-P04] Late Holocene vegetation dynamics in the Yangmingshan National Park, northern Taiwan

*Liang-Chi Wang¹ (1.National Chung Cheng University)

Keywords:Pollen, wetland development, water depth

This study was presented multi-decadal pollen and Itrax-XRF element record from the 180-cm sediment core of the Dream Lake (DL) in the Yangmingshan National Park at 860 m altitudes in northern Taiwan. High percentages of Poaceae pollen suggested the grassland as the dominant vegetation during the last 4500 cal BP period. The expanded wetland landscape during 4500-3500 cal BP was inferred by the increase of Cyperaceae pollen. The expansion of grassland may have markedly reduced wetland cover between 3500-3100 cal BP. During this period, the decrease of aquatic fern spore, Isoetes, which dominated the habitat with a water depth >30 cm, reflected a transition to dryer climatic conditions. The peat deposits with high pollen concentration suggested the stable lacustrine conditions of the last 3000 cal BP. The poor preservation of aquatic fern spores revealed that DL was the seasonal/intermittent freshwater ponds during this period.