Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations
An accelerator mass spectrometry (AMS- 14C) dated multi-proxy upper montane rainforest record from the Horton Plains, Central Sri Lanka reveals a ~ 24,000 year history of millennial-scale monsoon climate variability since the last glacial maximum (LGM). The vegetation history indicates that post-LGM...
Published in: | Journal of the National Science Foundation of Sri Lanka |
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Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
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National Science Foundation of Sri Lanka
2013
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Online Access: | http://www.sljol.info/index.php/JNSFSL/article/view/6057 https://doi.org/10.4038/jnsfsr.v41i3.6057 |
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ftjsrilankajo:oai:sljol.journals.sfu.ca:article/6057 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Sri Lanka Journals Online (SLJOL) |
op_collection_id |
ftjsrilankajo |
language |
English |
topic |
Holocene aridity; Palaeomonsoons; millennial cycles; rainforest diversity; regional chronology; Sri Lanka |
spellingShingle |
Holocene aridity; Palaeomonsoons; millennial cycles; rainforest diversity; regional chronology; Sri Lanka Premathilake, Ratnasiri Gunatilaka, Ananda Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations |
topic_facet |
Holocene aridity; Palaeomonsoons; millennial cycles; rainforest diversity; regional chronology; Sri Lanka |
description |
An accelerator mass spectrometry (AMS- 14C) dated multi-proxy upper montane rainforest record from the Horton Plains, Central Sri Lanka reveals a ~ 24,000 year history of millennial-scale monsoon climate variability since the last glacial maximum (LGM). The vegetation history indicates that post-LGM earliest tropical warming and monsoon initiation preceded the Northern Hemisphere ice-sheet melting by over 3000 years before the Bolling interval, with a significant increase in the precipitation at Termination 1A (event-B in the Horton Plains). This suggests a major early strengthening of the monsoon. Starting ca. 17,600 years before present (yr BP), the rainforest diversity increases in-step with four progressively increasing humid events (A-D) and interrupted by two relatively semi-arid/weak episodes of which the second (Termination 1B) ending ca. 10,400 yr BP may reflect a delayed Younger Dryas event. The optimum rainforest diversification coincides with the Holocene monsoon precipitation maximum ca. 9,200 − 8,800 yr BP (event-D). A disruption to these millennial cycles coincided with a gradual monsoon downturn, precipitation and rainforest decline and aridity between ca. 8,100 − 3,400 yr BP. The conditions became more humid again for rainforest expansions between ca. 3,400 − 1,500 yr BP (event-E). Broadly synchronous millennial-scale climatic records of the Horton Plains, Arabian Sea, Oman, Yemen and India, equatorial West and East Africa, and the North Atlantic regions indicate twoway teleconnections between the tropical Asian Monsoon fluctuations and high latitude events. The above changes reflect vast spatial rearrangements in atmospheric circulation patterns, probably caused by forcing associated with coupled ocean-atmosphere-vegetation feedbacks. There is a remarkably close correlation of the different proxies that has tracked the Southwest Monsoon variations across the region since the LGM.J.Natn.Sci.Foundation Sri Lanka 2013 41 (3): 219-228 DOI: http://dx.doi.org/10.4038/jnsfsr.v41i3.6057 |
format |
Article in Journal/Newspaper |
author |
Premathilake, Ratnasiri Gunatilaka, Ananda |
author_facet |
Premathilake, Ratnasiri Gunatilaka, Ananda |
author_sort |
Premathilake, Ratnasiri |
title |
Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations |
title_short |
Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations |
title_full |
Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations |
title_fullStr |
Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations |
title_full_unstemmed |
Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations |
title_sort |
chronological framework of asian southwest monsoon events and variations over the past 24,000 years in sri lanka and regional correlations |
publisher |
National Science Foundation of Sri Lanka |
publishDate |
2013 |
url |
http://www.sljol.info/index.php/JNSFSL/article/view/6057 https://doi.org/10.4038/jnsfsr.v41i3.6057 |
genre |
Ice Sheet North Atlantic |
genre_facet |
Ice Sheet North Atlantic |
op_source |
Journal of the National Science Foundation of Sri Lanka; Vol 41, No 3 (2013); 219-228 |
op_relation |
http://www.sljol.info/index.php/JNSFSL/article/view/6057/4759 |
op_rights |
Journal of the National Science Foundation of Sri LankaAUTHORS' RESPONSIBILITY STATEMENT(To be read and signed by each author)I/We certify that I/we have participated sufficiently in the conception, design and execution of this work and the analysis of the data (where applicable) as well as in the writing of the manuscript, to take public responsibility for it.I/We certify also that the material reported here represents original work carried out by me/us. Neither this manuscript nor one with substantially similar content under my/ our authorship has been published or is being considered for publication elsewhere, except as described in an annexure.I/We attest also that I/we shall produce the original data upon which the manuscript is based for examination by the editors or their assignees should they request it.I/We hereby transfer (s), assign (s), or otherwise convey (s) all copyright ownership, including any and all rights incidental thereto, exclusively to the Journal, in the event that such work is published by the Journal.We give the rights to the corresponding author to make necessary changes of the manuscript and he/she will act as the guarantor for the manuscript on our behalf.We hereby jointly and severally take responsibility for authorship of the above paper submitted for publication in the Journal of the National Science Foundation of Sri Lanka. |
op_doi |
https://doi.org/10.4038/jnsfsr.v41i3.6057 |
container_title |
Journal of the National Science Foundation of Sri Lanka |
container_volume |
41 |
container_issue |
3 |
container_start_page |
219 |
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1766031851154046976 |
spelling |
ftjsrilankajo:oai:sljol.journals.sfu.ca:article/6057 2023-05-15T16:41:25+02:00 Chronological framework of Asian Southwest Monsoon events and variations over the past 24,000 years in Sri Lanka and regional correlations Premathilake, Ratnasiri Gunatilaka, Ananda 2013-09-29 application/pdf http://www.sljol.info/index.php/JNSFSL/article/view/6057 https://doi.org/10.4038/jnsfsr.v41i3.6057 eng eng National Science Foundation of Sri Lanka http://www.sljol.info/index.php/JNSFSL/article/view/6057/4759 Journal of the National Science Foundation of Sri LankaAUTHORS' RESPONSIBILITY STATEMENT(To be read and signed by each author)I/We certify that I/we have participated sufficiently in the conception, design and execution of this work and the analysis of the data (where applicable) as well as in the writing of the manuscript, to take public responsibility for it.I/We certify also that the material reported here represents original work carried out by me/us. Neither this manuscript nor one with substantially similar content under my/ our authorship has been published or is being considered for publication elsewhere, except as described in an annexure.I/We attest also that I/we shall produce the original data upon which the manuscript is based for examination by the editors or their assignees should they request it.I/We hereby transfer (s), assign (s), or otherwise convey (s) all copyright ownership, including any and all rights incidental thereto, exclusively to the Journal, in the event that such work is published by the Journal.We give the rights to the corresponding author to make necessary changes of the manuscript and he/she will act as the guarantor for the manuscript on our behalf.We hereby jointly and severally take responsibility for authorship of the above paper submitted for publication in the Journal of the National Science Foundation of Sri Lanka. Journal of the National Science Foundation of Sri Lanka; Vol 41, No 3 (2013); 219-228 Holocene aridity; Palaeomonsoons; millennial cycles; rainforest diversity; regional chronology; Sri Lanka info:eu-repo/semantics/article Peer-Reviewed Article info:eu-repo/semantics/publishedVersion 2013 ftjsrilankajo https://doi.org/10.4038/jnsfsr.v41i3.6057 2013-10-29T08:35:50Z An accelerator mass spectrometry (AMS- 14C) dated multi-proxy upper montane rainforest record from the Horton Plains, Central Sri Lanka reveals a ~ 24,000 year history of millennial-scale monsoon climate variability since the last glacial maximum (LGM). The vegetation history indicates that post-LGM earliest tropical warming and monsoon initiation preceded the Northern Hemisphere ice-sheet melting by over 3000 years before the Bolling interval, with a significant increase in the precipitation at Termination 1A (event-B in the Horton Plains). This suggests a major early strengthening of the monsoon. Starting ca. 17,600 years before present (yr BP), the rainforest diversity increases in-step with four progressively increasing humid events (A-D) and interrupted by two relatively semi-arid/weak episodes of which the second (Termination 1B) ending ca. 10,400 yr BP may reflect a delayed Younger Dryas event. The optimum rainforest diversification coincides with the Holocene monsoon precipitation maximum ca. 9,200 − 8,800 yr BP (event-D). A disruption to these millennial cycles coincided with a gradual monsoon downturn, precipitation and rainforest decline and aridity between ca. 8,100 − 3,400 yr BP. The conditions became more humid again for rainforest expansions between ca. 3,400 − 1,500 yr BP (event-E). Broadly synchronous millennial-scale climatic records of the Horton Plains, Arabian Sea, Oman, Yemen and India, equatorial West and East Africa, and the North Atlantic regions indicate twoway teleconnections between the tropical Asian Monsoon fluctuations and high latitude events. The above changes reflect vast spatial rearrangements in atmospheric circulation patterns, probably caused by forcing associated with coupled ocean-atmosphere-vegetation feedbacks. There is a remarkably close correlation of the different proxies that has tracked the Southwest Monsoon variations across the region since the LGM.J.Natn.Sci.Foundation Sri Lanka 2013 41 (3): 219-228 DOI: http://dx.doi.org/10.4038/jnsfsr.v41i3.6057 Article in Journal/Newspaper Ice Sheet North Atlantic Sri Lanka Journals Online (SLJOL) Journal of the National Science Foundation of Sri Lanka 41 3 219 |