Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial Maximum

The Last Glacial Maximum (LGM) is a key reference point for understanding past climate, but its complexity can lead to ambiguities in scope and interpretation. In this study, we applied a suite of geochemical techniques -XRF, grain size, and pollen analysis- to a well-dated sedimentary sequence from...

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Main Authors: Akkaneewut Jirapinyakul, Dissaya Sukaudom, Chawalit Charoenpong, Penjai Sompongchaikul, Paramita Punwong, Kweku Afrifa Yamoah
Format: Article
Language:English
Published: Ubiquity Press 2025-07-01
Series:Open Quaternary
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Online Access:https://account.openquaternary.com/index.php/up-j-oq/article/view/154
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author Akkaneewut Jirapinyakul
Dissaya Sukaudom
Chawalit Charoenpong
Penjai Sompongchaikul
Paramita Punwong
Kweku Afrifa Yamoah
author_facet Akkaneewut Jirapinyakul
Dissaya Sukaudom
Chawalit Charoenpong
Penjai Sompongchaikul
Paramita Punwong
Kweku Afrifa Yamoah
author_sort Akkaneewut Jirapinyakul
collection DOAJ
description The Last Glacial Maximum (LGM) is a key reference point for understanding past climate, but its complexity can lead to ambiguities in scope and interpretation. In this study, we applied a suite of geochemical techniques -XRF, grain size, and pollen analysis- to a well-dated sedimentary sequence from the lower central plain of Thailand. Our results show a gradual increase in fluvial runoff and precipitation from 26.5 to 24.6 cal ka BP, followed by reduced discharge around 24.6–24.1 cal ka BP, correlating with Heinrich event 2. A subsequent decline in runoff until 23 cal ka BP was followed by a distinct increased precipitation between 23–22.8 cal ka BP, with an abrupt shift to drier conditions post 22.8 cal ka BP. Comparing our records with other paleo records from the Sundaland imply that the Intertropical Convergence Zone (ITCZ) did not shift significantly north during the LGM. Instead, we suggest an ENSO-like phenomenon modulated tropical rainfall during the LGM as a result of the exposed Sunda Shelf, which enhanced precipitation and created a climate similar to the present tropical wet-dry or savanna climate, with pronounced seasonality. Our results highlight the complexities associated with tropical climate variability, challenging the conventional uniformity of cool and dry conditions during the LGM.
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institution Kabale University
issn 2055-298X
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publishDate 2025-07-01
publisher Ubiquity Press
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series Open Quaternary
spelling doaj-art-a7767e599d9848a0b64aaeeb9ef24f282025-08-21T12:45:27ZengUbiquity PressOpen Quaternary2055-298X2025-07-01119910.5334/oq.154151Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial MaximumAkkaneewut Jirapinyakul0https://orcid.org/0000-0002-1167-8912Dissaya Sukaudom1Chawalit Charoenpong2https://orcid.org/0000-0001-6067-307XPenjai Sompongchaikul3Paramita Punwong4Kweku Afrifa Yamoah5https://orcid.org/0000-0001-7488-0459Center of Excellence in Morphology of Earth Surface and Advanced Geohazards in Southeast Asia (MESA CE), Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330; Earth Sciences Program, Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330Earth Sciences Program, Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok 10330Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok 10330Faculty of Environment and Resource Studies, Mahidol University, Phutthamonthon 4 Road, Salaya, Phutthamonthon, Nakhon Pathom 73170BioArCh, Department of Archaeology, University of York, Heslington, York YO10 5DDThe Last Glacial Maximum (LGM) is a key reference point for understanding past climate, but its complexity can lead to ambiguities in scope and interpretation. In this study, we applied a suite of geochemical techniques -XRF, grain size, and pollen analysis- to a well-dated sedimentary sequence from the lower central plain of Thailand. Our results show a gradual increase in fluvial runoff and precipitation from 26.5 to 24.6 cal ka BP, followed by reduced discharge around 24.6–24.1 cal ka BP, correlating with Heinrich event 2. A subsequent decline in runoff until 23 cal ka BP was followed by a distinct increased precipitation between 23–22.8 cal ka BP, with an abrupt shift to drier conditions post 22.8 cal ka BP. Comparing our records with other paleo records from the Sundaland imply that the Intertropical Convergence Zone (ITCZ) did not shift significantly north during the LGM. Instead, we suggest an ENSO-like phenomenon modulated tropical rainfall during the LGM as a result of the exposed Sunda Shelf, which enhanced precipitation and created a climate similar to the present tropical wet-dry or savanna climate, with pronounced seasonality. Our results highlight the complexities associated with tropical climate variability, challenging the conventional uniformity of cool and dry conditions during the LGM.https://account.openquaternary.com/index.php/up-j-oq/article/view/154the mainland southeast asiathe lower central plain of thailandsundalandmonsoonsavannah climate
spellingShingle Akkaneewut Jirapinyakul
Dissaya Sukaudom
Chawalit Charoenpong
Penjai Sompongchaikul
Paramita Punwong
Kweku Afrifa Yamoah
Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial Maximum
Open Quaternary
the mainland southeast asia
the lower central plain of thailand
sundaland
monsoon
savannah climate
title Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial Maximum
title_full Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial Maximum
title_fullStr Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial Maximum
title_full_unstemmed Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial Maximum
title_short Hydroclimate Variability in the Mainland Southeast Asia During the Last Glacial Maximum
title_sort hydroclimate variability in the mainland southeast asia during the last glacial maximum
topic the mainland southeast asia
the lower central plain of thailand
sundaland
monsoon
savannah climate
url https://account.openquaternary.com/index.php/up-j-oq/article/view/154
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