Hydroclimatic shifts in northeast Thailand during the last two millennia - the record of Lake Pa Kho

QUATERNARY SCIENCE REVIEWS

卷:111

Review

Chawchai, Sakonvan^1,2  Chabangborn, Akkaneewut^1,2  Fritz, Sherilyn^3,4  Valiranta, Minna⁵  Morth, Carl-Magnus¹  Blaauw, Maarten⁶  Reimer, Paula J.⁶  Krusic, Paul J.⁷  Lowemark, Ludvig⁸  Wohlfarth, Barbara¹ 

[1] Stockholm Univ, Dept Geol Sci, S-10691 Stockholm, Sweden

[2] Chulalongkorn Univ, Dept Geol, Fac Sci, Bangkok 10330, Thailand

[3] Univ Nebraska, Dept Earth & Atmospher Sci, Lincoln, NE 68588 USA

[4] Univ Nebraska, Sch Biol Sci, Lincoln, NE 68588 USA

[5] Univ Helsinki, Dept Environm Sci, Helsinki 4603, Finland

[6] Queens Univ Belfast, Ctr Climate Environm & Chronol 14CHRONO, Sch Geog Archaeol & Palaeoecol, Belfast BT7 1NN, Antrim, North Ireland

[7] Stockholm Univ, Dept Phys Geog & Quaternary Geol, S-10691 Stockholm, Sweden

[8] Natl Taiwan Univ, Dept Geosci, Taipei 106, Taiwan

关键词: Wetland/peatland;    Geochemistry;    Paleoclimate;    Last two millennia;    Asian monsoon;   

DOI  :  10.1016/j.quascirev.2015.01.007

来源: Elsevier

【 摘 要 】

The Southeast Asian mainland is located in the central path of the Asian summer monsoon, a region where paleoclimatic data are still sparse. Here we present a multi-proxy (TOC, C/N, delta C-13, biogenic silica, and XRF elemental data) study of a 1.5 m sediment/peat sequence from Lake Pa Kho, northeast Thailand, which is supported by 20 AMS C-14 ages. Hydroclimatic reconstructions for Pa Kho suggest a strengthened summer monsoon between BC 170-AD 370, AD 800-960, and after AD 1450; and a weakening of the summer monsoon between AD 370-800, and AD 1300-1450. Increased run-off and a higher nutrient supply after AD 1700 can be linked to agricultural intensification and land-use changes in the region. This study fills an important gap in data coverage with respect to summer monsoon variability over Southeast Asia during the past 2000 years and enables the mean position of the Intertropical Convergence Zone (ITCZ) to be inferred based on comparisons with other regional studies. Intervals of strengthened/weaker summer monsoon rainfall suggest that the mean position of the ITCZ was located as far north as 35 degrees N between BC 170-AD 370 and AD 800-960, whereas it likely did not reach above 17 degrees N during the drought intervals of AD 370-800 and AD 1300-1450. The spatial pattern of rainfall variation seems to have changed after AD 1450, when the inferred moisture history for Pa Kho indicates a more southerly location of the mean position of the summer ITCZ.

【 授权许可】

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