Drainage and erosion of Cambodia's great lake in the middle-late Holocene: The combined role of climatic drying, base-level fall and river capture

QUATERNARY SCIENCE REVIEWS

卷:236

Article

Darby, Stephen E.¹  Langdon, Peter G.¹  Best, James L.^2,3,4,5  Leyland, Julian¹  Hackney, Christopher R.⁶  Marti, Mackenzie^2,12  Morgan, Peter R.¹  Ben, Savuth⁷  Aalto, Rolf⁸  Parsons, Daniel R.⁹  Nicholas, Andrew P.⁸  Leng, Melanie J.^10,11 

[1] Univ Southampton, Sch Geog & Environm Sci, Southampton SO17 1BJ, Hants, England

[2] Univ Illinois, Dept Geol, Urbana, IL 61801 USA

[3] Univ Illinois, Dept Geog & GIS, Urbana, IL 61801 USA

[4] Univ Illinois, Dept Mech Sci & Engn, Urbana, IL 61801 USA

[5] Univ Illinois, Ven Te Chow Hydrosyst Lab, Urbana, IL 61801 USA

[6] Univ Newcastle, Sch Geog Polit & Sociol, Newcastle Upon Tyne NE1 7RD, NE, England

[7] Minist Mines & Energy, 79-89 Pasteur St, Khan Daun Penh, Phnom Penh, Cambodia

[8] Univ Exeter, Dept Geog, Exeter EX4 4RJ, Devon, England

[9] Univ Hull, Energy & Environm Inst, Kingston Upon Hull HU6 7RX, N Humberside, England

[10] British Geol Survey, Nottingham NG12 5GG, England

[11] Univ Nottingham, Ctr Environm Geochem, Sch Biosci, Loughborough LE12 5RD, Leics, England

[12] Illinois State Geol Survey, Prairie Res Inst, Champaign, IL 61820 USA

关键词: Tonle sap;    Holocene;    Paleogeography;    Paleolimnology;    Southeastern Asia;   

DOI  :  10.1016/j.quascirev.2020.106265

来源: Elsevier

【 摘 要 】

We provide evidence for a large-scale geomorphic event in Cambodia's great lake, the Tonle Sap, during the middle Holocene. The present-day hydrology of the basin is dominated by an annual flood pulse where water from the Mekong River raises the lake level by c. 8 m during the monsoon season. We present new subsurface geophysical data, allied to new and past core studies, which unequivocally show a period of major mid-Holocene erosion across the entire Tonle Sap basin that is coincident with establishment of the lake's flood pulse. We argue that this widespread erosion, which removed at least 1.2 m of sediment across the lake's extent, was triggered by up to three, likely interacting, processes: (1) base-level lowering due to mid-Holocene sea-level fall, leading to (2) capture of the Tonle Sap drainage by the Mekong River, and (3) a drying climate that also reduced lake level. Longer-term landscape evolution was thus punctuated by a rapid, river capture- and base-level fall- induced, lake drainage that established the ecosystem that flourishes today. The scale of change induced by this mid-Holocene river capture event demonstrates the susceptibility of the Tonle Sap lake to ongoing changes in local base-level and hydrology induced by anthropogenic activity, such as damming and sand mining, within the Mekong River Basin. (C) 2020 Elsevier Ltd. All rights reserved.

【 授权许可】

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