Quartz OSL sensitivity as a proxy for storm activity on the southern Brazilian coast during the Late Holocene
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
07/11/2013
07/11/2013
2012
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Resumo |
Natural cycles of irradiation during burial and bleaching due to solar exposure during transport increase the Optically Stimulated Luminescence (OSL) sensitivity of quartz sand grains. The relationship between the OSL sensitivity and sediment transport allows to discriminate quartz sand grains with different depositional histories. In this paper, we evaluate the variation of OSL sensitivity in quartz grains deposited during the progradation of the Ilha Comprida barrier on the southern Brazilian, coast. Changes in sand sensitivity recorded by barrier growth since 6 ka ago are controlled by the variation in the proportion of low versus high sensitivity quartz grains. Low sensitivity grains with short sedimentary history are supplied by the Ribeira de Iguape River and reach the barrier through southward alongshore currents during fair weather conditions. Storm conditions shift the alongshore currents to northeast and permit the transport of high sensitivity grains with long sedimentary history from distal southern coastal sectors to the barrier. Therefore, the input of distal sediments for the Ilha Comprida barrier depends on the frequency and intensity of storms. Thus, the OSL sensitivity can be used as proxy for storm activity. The variation of OSL sensitivity through time indicates that the Ilha Comprida barrier changed from a relatively stable to an unstable storm pattern around 2 ka ago. Periods with increased storm activity peaked around AD 500, AD 1500 and AD 1850, approximately on the boundaries of the Medieval Climate Anomaly and the Little Ice Age. (C) 2012 Elsevier B.V. All rights reserved. Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2007/54889-8] |
Identificador |
QUATERNARY GEOCHRONOLOGY, OXFORD, v. 13, n. 1, supl. 1, Part 1, pp. 92-102, DEC, 2012 1871-1014 http://www.producao.usp.br/handle/BDPI/43264 10.1016/j.quageo.2012.07.002 |
Idioma(s) |
eng |
Publicador |
ELSEVIER SCI LTD OXFORD |
Relação |
QUATERNARY GEOCHRONOLOGY |
Direitos |
closedAccess Copyright ELSEVIER SCI LTD |
Palavras-Chave | #QUARTZ LUMINESCENCE #SAND PROVENANCE #COASTAL BARRIER #LATE HOLOCENE CLIMATE CHANGE #SOUTHERN BRAZIL #LUMINESCENCE SENSITIVITY #SANTA-CATARINA #BARRIER #GRAINS #THERMOLUMINESCENCE #PROVENANCE #TRANSPORT #SEDIMENTS #TEMPERATURE #INTENSITY #GEOGRAPHY, PHYSICAL #GEOSCIENCES, MULTIDISCIPLINARY |
Tipo |
article original article publishedVersion |