Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia
Despite its potential linkages with North Atlantic climate, the variability in Saharan dust transport to the western North Atlantic over the past two millennia has not been well-characterized. A factor of 4 increase in dust production in sub-Saharan Africa has been attributed to the onset of Sahelia...
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ftmit:oai:dspace.mit.edu:1721.1/120510 2023-06-11T04:14:18+02:00 Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia Mukhopadhyay, Sujoy Maloof, Adam C. Hayes, Christopher Tyler McGee, William David Boyle, Edward A Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Boyle, Edward Hayes, Christopher Tyler McGee, William David Boyle, Edward A 2016-09 application/pdf http://hdl.handle.net/1721.1/120510 en_US eng Elsevier https://doi.org/10.1016/j.epsl.2016.10.031 Earth and Planetary Science Letters 0012-821X http://hdl.handle.net/1721.1/120510 Hayes, Christopher T. et al. “Helium and Thorium Isotope Constraints on African Dust Transport to the Bahamas over Recent Millennia.” Earth and Planetary Science Letters 457 (January 2017): 385–394 © 2016 Elsevier B.V. orcid:0000-0002-6394-1866 Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ Prof. Boyle via Chris Sherratt Article http://purl.org/eprint/type/JournalArticle 2016 ftmit https://doi.org/10.1016/j.epsl.2016.10.031 2023-05-29T08:28:55Z Despite its potential linkages with North Atlantic climate, the variability in Saharan dust transport to the western North Atlantic over the past two millennia has not been well-characterized. A factor of 4 increase in dust production in sub-Saharan Africa has been attributed to the onset of Sahelian agriculture 200 yr ago. The regional extent of this anthropogenic dust increase, however, remains uncertain. Additionally, while millennial-scale cold periods of the last deglaciation have been associated with strong increases in North African dust emissions, few adequate records exist to observe dustiness during the Little Ice Age, a century-scale cooling of the North Atlantic (AD 1400–1800). In this study, we develop a new technique for the paired use of ²³⁰Th-normalized ²³²Th fluxes and ³He-normalized ⁴He fluxes in Bahamian tidal flat sediments. After justifying the fact that ²³⁰Th and ³He have had relatively constant sources to tidal flat and banktop waters, and accounting for the smoothing effect of bioturbation, a factor of 4 change in far-field dust transport to the western North Atlantic between the pre-industrial and modern era is not supported by our dust proxies over the past 2000 yr. Furthermore, we speculate why the response of western North Atlantic dust deposition associated with the Little Ice Age climate anomalies may have been modest compared to prior climatic events of the early Holocene or the last deglaciation. Keywords: aerosols; mineral dust; thorium isotopes; Anthropocene; Little Ice Age Article in Journal/Newspaper North Atlantic DSpace@MIT (Massachusetts Institute of Technology) Earth and Planetary Science Letters 457 385 394 |
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DSpace@MIT (Massachusetts Institute of Technology) |
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ftmit |
language |
English |
description |
Despite its potential linkages with North Atlantic climate, the variability in Saharan dust transport to the western North Atlantic over the past two millennia has not been well-characterized. A factor of 4 increase in dust production in sub-Saharan Africa has been attributed to the onset of Sahelian agriculture 200 yr ago. The regional extent of this anthropogenic dust increase, however, remains uncertain. Additionally, while millennial-scale cold periods of the last deglaciation have been associated with strong increases in North African dust emissions, few adequate records exist to observe dustiness during the Little Ice Age, a century-scale cooling of the North Atlantic (AD 1400–1800). In this study, we develop a new technique for the paired use of ²³⁰Th-normalized ²³²Th fluxes and ³He-normalized ⁴He fluxes in Bahamian tidal flat sediments. After justifying the fact that ²³⁰Th and ³He have had relatively constant sources to tidal flat and banktop waters, and accounting for the smoothing effect of bioturbation, a factor of 4 change in far-field dust transport to the western North Atlantic between the pre-industrial and modern era is not supported by our dust proxies over the past 2000 yr. Furthermore, we speculate why the response of western North Atlantic dust deposition associated with the Little Ice Age climate anomalies may have been modest compared to prior climatic events of the early Holocene or the last deglaciation. Keywords: aerosols; mineral dust; thorium isotopes; Anthropocene; Little Ice Age |
author2 |
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Boyle, Edward Hayes, Christopher Tyler McGee, William David Boyle, Edward A |
format |
Article in Journal/Newspaper |
author |
Mukhopadhyay, Sujoy Maloof, Adam C. Hayes, Christopher Tyler McGee, William David Boyle, Edward A |
spellingShingle |
Mukhopadhyay, Sujoy Maloof, Adam C. Hayes, Christopher Tyler McGee, William David Boyle, Edward A Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia |
author_facet |
Mukhopadhyay, Sujoy Maloof, Adam C. Hayes, Christopher Tyler McGee, William David Boyle, Edward A |
author_sort |
Mukhopadhyay, Sujoy |
title |
Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia |
title_short |
Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia |
title_full |
Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia |
title_fullStr |
Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia |
title_full_unstemmed |
Helium and thorium isotope constraints on African dust transport to the Bahamas over recent millennia |
title_sort |
helium and thorium isotope constraints on african dust transport to the bahamas over recent millennia |
publisher |
Elsevier |
publishDate |
2016 |
url |
http://hdl.handle.net/1721.1/120510 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Prof. Boyle via Chris Sherratt |
op_relation |
https://doi.org/10.1016/j.epsl.2016.10.031 Earth and Planetary Science Letters 0012-821X http://hdl.handle.net/1721.1/120510 Hayes, Christopher T. et al. “Helium and Thorium Isotope Constraints on African Dust Transport to the Bahamas over Recent Millennia.” Earth and Planetary Science Letters 457 (January 2017): 385–394 © 2016 Elsevier B.V. orcid:0000-0002-6394-1866 |
op_rights |
Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1016/j.epsl.2016.10.031 |
container_title |
Earth and Planetary Science Letters |
container_volume |
457 |
container_start_page |
385 |
op_container_end_page |
394 |
_version_ |
1768392225697300480 |