Lake Kumphawapi e an archive of Holocene palaeoenvironmental and palaeoclimatic changes in northeast Thailand
S. Chawchai a,*, A. Chabangborn a, M. Kylander a, L. Löwemark b, C.-M. Mörth a, M. Blaauw c, W. Klubseang d,e, P.J. Reimer c, S.C. Fritz f, B. Wohlfarth a
a Department of Geological Sciences, Stockholm University, SE-10961 Stockholm, Sweden
b Department of Geosciences, National Taiwan University, No 1, Sec. 4, Roosevelt Road, P.O. Box 13-318, 106 Taipei, Taiwan
c Centre for Climate, the Environment & Chronology (14CHRONO), School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, Belfast BT7 1NN, UK
d Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
e Institute for the Promotion of Teaching Science and Technology, 924 Sukhumvit Rd., Bangkok 10110, Thailand
f Department of Earth and Atmospheric Sciences and School of Biological Sciences, University of Nebraska e Lincoln, 214 Bessey Hall, Lincoln 68588-0340, USA
a b s t r a c t
The long-term climatic and environmental history of Southeast Asia, and of Thailand in particular, is still fragmentary. Here we present a new 14C-dated, multi-proxy sediment record (TOC, C/N, CNS isotopes, Si, Zr, K, Ti, Rb, Ca elemental data, biogenic silica) for Lake Kumphawapi, the second largest natural lake in northeast Thailand. The data set provides a reconstruction of changes in lake status, groundwater fluctuations, and catchment run-off during the Holocene. A comparison of multiple sediment sequences and their proxies suggests that the summer monsoon was stronger between c. 9800 and 7000 cal yr BP. Lake status and water level changes around 7000 cal yr BP signify a shift to lower effective moisture. By c. 6500 cal yr BP parts of the lake had been transformed into a peatland, while areas of shallow water still occupied the deeper part of the basin until c. 5400e5200 cal yr BP. The driest interval in Kumphawapi’s history occurred between c. 5200 and 3200 cal yr BP, when peat extended over large parts of the basin. After 3200 cal yr BP, the deepest part of the lake again turned into a wetland, which existed until c. 1600 cal yr BP. The observed lake-level rise after 1600 cal yr BP could have been caused by higher moisture availability, although increased human influence in the catchment cannot be ruled out. The present study highlights the use of multiple sediment sequences and proxies to study large lakes, such as Lake Kumphawapi in order to correctly assess the time transgressive response to past changes in hydroclimate conditions. Our new data set from northeast Thailand adds important palaeoclimatic information for a region in Southeast Asia and allows discussing Holocene monsoon variability and ITCZ movement in greater detail.
2013 Elsevier Ltd. All rights reserved. Quaternary Science Reviews 68 (2013) 59e75
