Late-Holocene sea-level markers preserved in a beach ridge system on Phra Thong Island, Thailand

Rahul Kumar; Adam D. Switzer; Chris Gouramanis; Charles S. Bristow; Timothy A. Shaw; Kruawun Jankaew; Tanghua Li; Dominik Brill

doi:10.1016/j.geomorph.2024.109405

Late-Holocene sea-level markers preserved in a beach ridge system on Phra Thong Island, Thailand

Rahul Kumar^*
, Adam D. Switzer
, Chris Gouramanis
, Charles S. Bristow
, Timothy A. Shaw
, Kruawun Jankaew
, Tanghua Li
, Dominik Brill

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

6 Citations (Scopus)

3 Downloads (CityUHK Scholars)

Abstract

Instrumental sea-level records are insufficient to understand the response of sea-level changes to global temperature on centennial timescales. Sea-level histories spanning at least the Common Era have not been widely studied in Southeast Asia. This period is crucial for providing a pre-industrial context to understand sea-level change with climate. Linking sea-level change to climate change is proxy dependant, with most proxies only providing decadal to centennial scale resolution of both sea level and climate. This study examines the efficiency of beach ridge stratigraphy as a proxy for reconstructing regional sea-level histories in the tropics. We present topographically corrected Ground Penetrating Radar (GPR) profiles from a prograded coast in Phra Thong Island, Thailand, where we identify downlap point marking the boundary between the foreshore and shoreface subzones and use this as a past low-tide marker. The low-tide markers were corrected (considering the tidal range) and then connected to approximate the past sea level. Optically Stimulated Luminescence (OSL) samples collected at locations slightly offset from the shore-normal GPR profile line were incorporated to create a relative sea-level record. Overall, the shore-normal GPR record shows a ∼ 1.06 m fall in sea level between ∼2660 and ∼ 370 years ago. The study also highlighted stepwise fluctuations in sea level that were not identified in previous studies. Between ∼2600 and ∼ 2200 years ago, the record indicates a steep fall in sea level, followed by a phase of relatively stable to slightly falling sea level between ∼2200 and ∼ 550 years ago. Finally, for the seaward side, between ∼550 and ∼ 350 years ago, the record indicates an accelerating sea-level fall. This study confirms that the investigation of tropical beach ridge systems using GPR and OSL techniques can be a highly efficient and effective means for reconstructing regional sea-level trends throughout the Common Era and beyond. © 2024 The Authors. Published by Elsevier B.V.

Original language	English
Article number	109405
Journal	Geomorphology
Volume	465
Online published	27 Aug 2024
DOIs	https://doi.org/10.1016/j.geomorph.2024.109405
Publication status	Published - 15 Nov 2024
Externally published	Yes

Funding

The authors are grateful to Mr. T. Chuoi for his hospitality and to the landowners who granted us access to the study area. This article is a contribution to IGCP Project 725 \u201CForecasting Coastal Change\u201D. This research was supported by the RT16/21 Singapore Ministry of Education Academic Research Fund and the Singapore National Research Foundation fellowship scheme (Grant No: NRF-RF2010-04) awarded to A.D.S. Additional funding came from the Singapore Ministry of Education Academic Research Fund MOE2019-T3-1-004 to support A.D.S and T.A.S. T.L. is supported by the Singapore Ministry of Education Academic Research Fund MOE-T2EP50120-0007. This is Earth Observatory of Singapore contribution number 564.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 13 Climate Action

Research Keywords

Beach ridge system
Downlap point
Ground penetrating radar
Late Holocene
Prograded coast
Sea-level marker

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This full text is made available under CC-BY 4.0. https://creativecommons.org/licenses/by/4.0/

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title = "Late-Holocene sea-level markers preserved in a beach ridge system on Phra Thong Island, Thailand",

abstract = "Instrumental sea-level records are insufficient to understand the response of sea-level changes to global temperature on centennial timescales. Sea-level histories spanning at least the Common Era have not been widely studied in Southeast Asia. This period is crucial for providing a pre-industrial context to understand sea-level change with climate. Linking sea-level change to climate change is proxy dependant, with most proxies only providing decadal to centennial scale resolution of both sea level and climate. This study examines the efficiency of beach ridge stratigraphy as a proxy for reconstructing regional sea-level histories in the tropics. We present topographically corrected Ground Penetrating Radar (GPR) profiles from a prograded coast in Phra Thong Island, Thailand, where we identify downlap point marking the boundary between the foreshore and shoreface subzones and use this as a past low-tide marker. The low-tide markers were corrected (considering the tidal range) and then connected to approximate the past sea level. Optically Stimulated Luminescence (OSL) samples collected at locations slightly offset from the shore-normal GPR profile line were incorporated to create a relative sea-level record. Overall, the shore-normal GPR record shows a ∼ 1.06 m fall in sea level between ∼2660 and ∼ 370 years ago. The study also highlighted stepwise fluctuations in sea level that were not identified in previous studies. Between ∼2600 and ∼ 2200 years ago, the record indicates a steep fall in sea level, followed by a phase of relatively stable to slightly falling sea level between ∼2200 and ∼ 550 years ago. Finally, for the seaward side, between ∼550 and ∼ 350 years ago, the record indicates an accelerating sea-level fall. This study confirms that the investigation of tropical beach ridge systems using GPR and OSL techniques can be a highly efficient and effective means for reconstructing regional sea-level trends throughout the Common Era and beyond. {\textcopyright} 2024 The Authors. Published by Elsevier B.V.",

keywords = "Beach ridge system, Downlap point, Ground penetrating radar, Late Holocene, Prograded coast, Sea-level marker",

author = "Rahul Kumar and Switzer, \{Adam D.\} and Chris Gouramanis and Bristow, \{Charles S.\} and Shaw, \{Timothy A.\} and Kruawun Jankaew and Tanghua Li and Dominik Brill",

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AU - Kumar, Rahul

AU - Switzer, Adam D.

AU - Gouramanis, Chris

AU - Bristow, Charles S.

AU - Shaw, Timothy A.

AU - Jankaew, Kruawun

AU - Li, Tanghua

AU - Brill, Dominik

PY - 2024/11/15

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N2 - Instrumental sea-level records are insufficient to understand the response of sea-level changes to global temperature on centennial timescales. Sea-level histories spanning at least the Common Era have not been widely studied in Southeast Asia. This period is crucial for providing a pre-industrial context to understand sea-level change with climate. Linking sea-level change to climate change is proxy dependant, with most proxies only providing decadal to centennial scale resolution of both sea level and climate. This study examines the efficiency of beach ridge stratigraphy as a proxy for reconstructing regional sea-level histories in the tropics. We present topographically corrected Ground Penetrating Radar (GPR) profiles from a prograded coast in Phra Thong Island, Thailand, where we identify downlap point marking the boundary between the foreshore and shoreface subzones and use this as a past low-tide marker. The low-tide markers were corrected (considering the tidal range) and then connected to approximate the past sea level. Optically Stimulated Luminescence (OSL) samples collected at locations slightly offset from the shore-normal GPR profile line were incorporated to create a relative sea-level record. Overall, the shore-normal GPR record shows a ∼ 1.06 m fall in sea level between ∼2660 and ∼ 370 years ago. The study also highlighted stepwise fluctuations in sea level that were not identified in previous studies. Between ∼2600 and ∼ 2200 years ago, the record indicates a steep fall in sea level, followed by a phase of relatively stable to slightly falling sea level between ∼2200 and ∼ 550 years ago. Finally, for the seaward side, between ∼550 and ∼ 350 years ago, the record indicates an accelerating sea-level fall. This study confirms that the investigation of tropical beach ridge systems using GPR and OSL techniques can be a highly efficient and effective means for reconstructing regional sea-level trends throughout the Common Era and beyond. © 2024 The Authors. Published by Elsevier B.V.

AB - Instrumental sea-level records are insufficient to understand the response of sea-level changes to global temperature on centennial timescales. Sea-level histories spanning at least the Common Era have not been widely studied in Southeast Asia. This period is crucial for providing a pre-industrial context to understand sea-level change with climate. Linking sea-level change to climate change is proxy dependant, with most proxies only providing decadal to centennial scale resolution of both sea level and climate. This study examines the efficiency of beach ridge stratigraphy as a proxy for reconstructing regional sea-level histories in the tropics. We present topographically corrected Ground Penetrating Radar (GPR) profiles from a prograded coast in Phra Thong Island, Thailand, where we identify downlap point marking the boundary between the foreshore and shoreface subzones and use this as a past low-tide marker. The low-tide markers were corrected (considering the tidal range) and then connected to approximate the past sea level. Optically Stimulated Luminescence (OSL) samples collected at locations slightly offset from the shore-normal GPR profile line were incorporated to create a relative sea-level record. Overall, the shore-normal GPR record shows a ∼ 1.06 m fall in sea level between ∼2660 and ∼ 370 years ago. The study also highlighted stepwise fluctuations in sea level that were not identified in previous studies. Between ∼2600 and ∼ 2200 years ago, the record indicates a steep fall in sea level, followed by a phase of relatively stable to slightly falling sea level between ∼2200 and ∼ 550 years ago. Finally, for the seaward side, between ∼550 and ∼ 350 years ago, the record indicates an accelerating sea-level fall. This study confirms that the investigation of tropical beach ridge systems using GPR and OSL techniques can be a highly efficient and effective means for reconstructing regional sea-level trends throughout the Common Era and beyond. © 2024 The Authors. Published by Elsevier B.V.

KW - Beach ridge system

KW - Downlap point

KW - Ground penetrating radar

KW - Late Holocene

KW - Prograded coast

KW - Sea-level marker

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DO - 10.1016/j.geomorph.2024.109405

M3 - RGC 21 - Publication in refereed journal

SN - 0169-555X

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JO - Geomorphology

JF - Geomorphology

M1 - 109405

ER -

Late-Holocene sea-level markers preserved in a beach ridge system on Phra Thong Island, Thailand

Abstract

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UN SDGs

Research Keywords

Publisher's Copyright Statement

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