Hydroclimate variability from western Iberia (Portugal) during the Holocene: Insights from a composite stalagmite isotope record

dc.contributor.author Thatcher, Diana
dc.contributor.author Wanamaker, Alan
dc.contributor.author Wanamaker, Alan
dc.contributor.author Denniston, Rhawn
dc.contributor.author Asmerom, Yemane
dc.contributor.author Polyak, Victor
dc.contributor.author Fullick, Daniel
dc.contributor.author Ummenhofer, Caroline
dc.contributor.author Gillikin, David
dc.contributor.author Haws, Jonathan
dc.contributor.department Geological and Atmospheric Sciences
dc.date 2020-07-13T21:06:07.000
dc.date.accessioned 2021-02-25T23:43:53Z
dc.date.available 2021-02-25T23:43:53Z
dc.date.copyright Wed Jan 01 00:00:00 UTC 2020
dc.date.issued 2020-01-01
dc.description.abstract <p>Iberia is predicted under future warming scenarios to be increasingly impacted by drought. While it is known that this region has experienced multiple intervals of enhanced aridity over the Holocene, additional hydroclimate-sensitive records from Iberia are necessary to place current and future drying into a broader perspective. Toward that end, we present a multi-proxy composite record from six well-dated and overlapping speleothems from Buraca Gloriosa (BG) cave, located in western Portugal. The coherence between the six stalagmites in this composite stalagmite record illustrates that climate (not in-cave processes) impacts speleothem isotopic values. This record provides the first high-resolution, precisely dated, terrestrial record of Holocene hydroclimate from west-central Iberia. The BG record reveals that aridity in western Portugal increased secularly from 9.0 ka BP to present, as evidenced by rising values of both carbon (δ<sup>13</sup>C) and oxygen (δ<sup>18</sup>O) stable isotope values. This trend tracks the decrease in Northern Hemisphere summer insolation and parallels Iberian margin sea surface temperatures (SST). The increased aridity over the Holocene is consistent with changes in Hadley Circulation and a southward migration of the Intertropical Convergence Zone (ITCZ). Centennial-scale shifts in hydroclimate are coincident with changes in total solar irradiance (TSI) after 4 ka BP. Several major drying events are evident, the most prominent of which was centered around 4.2 ka BP, a feature also noted in other Iberian climate records and coinciding with well-documented regional cultural shifts. Substantially, wetter conditions occurred from 0.8 ka BP to 0.15 ka BP, including much of the ‘Little Ice Age’. This was followed by increasing aridity toward present day. This composite stalagmite proxy record complements oceanic records from coastal Iberia, lacustrine records from inland Iberia, and speleothem records from both northern and southern Spain and depicts the spatial and temporal variability in hydroclimate in Iberia.</p>
dc.description.comments <p>This article is published as Thatcher, Diana L., Alan D. Wanamaker, Rhawn F. Denniston, Yemane Asmerom, Victor J. Polyak, Daniel Fullick, Caroline C. Ummenhofer, David P. Gillikin, and Jonathan A. Haws. "Hydroclimate variability from western Iberia (Portugal) during the Holocene: Insights from a composite stalagmite isotope record." <em>The Holocene</em> 30 (2020): 966-981. doi: <a href="https://doi.org/10.1177%2F0959683620908648">10.1177/0959683620908648</a>.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/ge_at_pubs/301/
dc.identifier.articleid 1310
dc.identifier.contextkey 18505731
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath ge_at_pubs/301
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/96323
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/ge_at_pubs/301/2020_Wanamaker_HydroclimateVariability.pdf|||Fri Jan 14 23:28:14 UTC 2022
dc.source.uri 10.1177/0959683620908648
dc.subject.disciplines Climate
dc.subject.disciplines Environmental Monitoring
dc.subject.disciplines Hydrology
dc.subject.keywords drought
dc.subject.keywords Holocene
dc.subject.keywords hydroclimate
dc.subject.keywords Iberia
dc.subject.keywords Portugal
dc.subject.keywords stalagmite
dc.title Hydroclimate variability from western Iberia (Portugal) during the Holocene: Insights from a composite stalagmite isotope record
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 0888f196-5404-41d6-a609-1ab839a739c6
relation.isOrgUnitOfPublication 29272786-4c4a-4d63-98d6-e7b6d6730c45
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