Paleoclimate reconstructions over the last century from a tropical speleothem on Niue Island, South Pacific

Show simple item record

dc.contributor Andrus, C. Fred T.
dc.contributor Donahoe, Rona Jean
dc.contributor Mylroie, John
dc.contributor Tick, Geoffrey R.
dc.contributor.advisor Aharon, Paul
dc.contributor.author Murgulet, Valeriu
dc.date.accessioned 2017-02-28T22:31:23Z
dc.date.available 2017-02-28T22:31:23Z
dc.date.issued 2010
dc.identifier.other u0015_0000001_0000362
dc.identifier.other Murgulet_alatus_0004D_10401
dc.identifier.uri https://ir.ua.edu/handle/123456789/868
dc.description Electronic Thesis or Dissertation
dc.description.abstract The study examines the question whether speleothems from Niue Island (19°00'S, 169°50'W), a large carbonate platform located at the edge of West Pacific Warm Pool, can serve as archives of hydroclimate controlled by El-Niño/Southern Oscillation (ENSO) and of catastrophic cyclones that frequent the island. Niue Island is heavily karstified, with modern and fossil speleothems hosted by coastal and inland caves. The flank margin caves on Niue are shown to be formed by the action of corrosive groundwaters on uplifted Pleistocene-age reef carbonates in a tectonically active region. The focus of this study is an actively growing stalagmite sampled from a flank margin cave (Avaiki Cave) that contains about 146 years of deposition (2002-1856 AD). The stalagmite consists of sub-annual couplets alternating between white porous calcite laminae deposited during the austral summer and dark, compact calcite laminae deposited during the austral relatively dry winter. High resolution (sub-annual) stable isotope and trace element profiles accompanied by trace element X-ray mapping were used to test the validity of ENSO-controlled hydroclimate and tropical cyclones archived in the stalagmite. The results show that interannual variability in the stalagmite d18O and d13C time series agrees well with instrumental-derived ENSO phases (El Niño and La Niña events during 1866-2002) and the sea level pressure differential (Samoa-Fiji)-based SPCZ index (SPI) that controls the interdecadal hydroclimate variability. Severe cyclones that directly impacted Niue Island over the last century are recorded by abrupt, large increases in trace element concentration values of Mg, and S accompanied by stable isotope positive excursions bearing seawater-derived signatures. Application of selected trace elements (i.e., Mg, Na, S, P) as proxies of severe storms is a novel technique that can be successfully applied in carbonate coastal areas with flank-margin caves impacted by severe cyclones. This study also demonstrates that sub-annual geochemical cycles in trace element laminae, unresolved by analytical linear transects due their complex distribution pattern, are successfully imaged by large area X-ray mapping of the stalagmite
dc.format.extent 196 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Geology
dc.subject.other Geochemistry
dc.title Paleoclimate reconstructions over the last century from a tropical speleothem on Niue Island, South Pacific
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Dept. of Geological Sciencess
etdms.degree.discipline Geology
etdms.degree.grantor The University of Alabama
etdms.degree.level doctoral
etdms.degree.name Ph.D.


Files in this item

This item appears in the following Collection(s)

Show simple item record

Search DSpace


Browse

My Account