$$\newcommand{\bra}[1]{\left<#1\right|}\newcommand{\ket}[1]{\left|#1\right>}\newcommand{\bk}[2]{\left<#1\middle|#2\right>}\newcommand{\bke}[3]{\left<#1\middle|#2\middle|#3\right>}$$
X
INFORMAÇÕES SOBRE DIREITOS AUTORAIS


As obras disponibilizadas nesta Biblioteca Digital foram publicadas sob expressa autorização dos respectivos autores, em conformidade com a Lei 9610/98.

A consulta aos textos, permitida por seus respectivos autores, é livre, bem como a impressão de trechos ou de um exemplar completo exclusivamente para uso próprio. Não são permitidas a impressão e a reprodução de obras completas com qualquer outra finalidade que não o uso próprio de quem imprime.

A reprodução de pequenos trechos, na forma de citações em trabalhos de terceiros que não o próprio autor do texto consultado,é permitida, na medida justificada para a compreeensão da citação e mediante a informação, junto à citação, do nome do autor do texto original, bem como da fonte da pesquisa.

A violação de direitos autorais é passível de sanções civis e penais.
Coleção Digital

Avançada


Estatísticas | Formato DC | MARC |



Título: HIGH RESOLUTION RECONSTRUCTION OF PALEOENVIRONMENTAL VARIATIONS OVER THE LAST 14 KYEARS IN SEDIMENTS OF RIO DE JANEIRO CONTINENTAL SHELF, SE - BRAZIL
Autor: LETICIA LAZZARI
Instituição: PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO - PUC-RIO
Colaborador(es):  RENATO DA SILVA CARREIRA - ADVISOR
ANGELA DE LUCA REBELLO WAGENER - CO-ADVISOR

Nº do Conteudo: 49015
Catalogação:  20/07/2020 Idioma(s):  PORTUGUESE - BRAZIL
Tipo:  TEXT Subtipo:  THESIS
Natureza:  SCHOLARLY PUBLICATION
Nota:  Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio.
Referência [pt]:  https://www.maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=49015@1
Referência [en]:  https://www.maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=49015@2
Referência DOI:  https://doi.org/10.17771/PUCRio.acad.49015

Resumo:
Paleoenvironmental studies on climate reconstructions in the past help to understand the current biogeochemical processes and therefore become increasingly important in the current scenario of global changes. The main parameters used in these studies involve proxies that require the integration of geochemical, geomorphological, oceanographic and biological information. In this study two cores (RJ13-01 and RJ13-02) were collected on the continental shelf of Rio de Janeiro in the isobath 100-m and dated by 210Pb and 14C methods covering14.5 cal kyr BP and 5.3 cal kyr BP, respectively. The main goal of this work was to investigate the effect of climatic and environmental variables on the autochthonous and allochthonous material inputs in the continental shelf of Rio de Janeiro. For this, geophysical properties, grain size, trace elements (V, Cr, Mn, Ni, Cu, Zn, As, Sr, Ag, Cd, Sn, Ba, Tl, Pb and U), major elements (Ca, Si, Al and Fe), total nitrogen (TN), total organic carbon (TOC), calcium carbonate (CaCO3), aliphatic hydrocarbons (n-alkanes) and polycyclic aromatic hydrocarbons (PAHs) were considered jointly with continental and biogenic input proxies, redoxsensitive and productivity proxies besides vegetation type and combustion proxies. Results highlighted three periods: the first period (from 14.5 to 7.5 cal kyr BP) with the occurrence of mean grain size of the sediment, shell fragments, high content of Si (27 percent), high input of biogenic material Ca/Al (3.00) and high ACL (average chain length) values (30.5). In addition to high contribution of pyrogenic PAHs (33 percent) around 8.0 cal kyr BP indicating higher incidence of dry weather in most periods; marked by a low sea level. The second period between 7.5 cal kyr BP and 4.5 cal kyr BP showed the influence of the South Atlantic Central Waters (SACW) marked by a maximum transgression of the sea, drought events with greater intensity of wildfires with high contribution of pyrogenic PAHs of 5-6 rings (68 percent) between 6.1 and 4.1 cal BP kyr BP and high input continental materials Al/Ca (0.69); Fe/Ca (0.27) and high productivity. The third period covers the late Holocene from 4.5 cal kyr BP to present. In this period, higher fluxes of organic matter were found between 3.2 cal kyr BP to 3.3 cal kyr BP (RJ13-01) and 3.4 cal kyr BP (RJ13-02), as indicated by TN, TOC, Ni, Cu,Zn, n-alkanes and PAHs, and higher continental input due to high redox-sensitive proxies from 2.5 cal kyr BP in RJ13-01 and along RJ13-02. These factors are probably related to the displacement further south of the Intertropical Convergence Zone (ITCZ), which brought humidity to Amazon, the intensification of SAMS bringing humidity to SE of Brazil trought SACZ. Also has been marked by the decrease in sea level which influenced the oxygen levels in the water column. On the other hand, dry climate indicators (ACL, pyrogenic PAHs with high molecular weight) suggest that there were fluctuations between wet and dry climate along the late Holocene. Thus, the organic and inorganic proxies considered on the cores of continental shelf of Rio de Janeiro allowed to evaluate and corroborate the data of other studies of climate events over the past 14,000 years in SE Brazil and their relation to the facts such is the variations in the sea-level, chances in ITCZ, the intensification of SAMS and SACZ, changes in wind pattern, and in the Brazilian current; influence of the SACW further S-W of the Cabo Frio upwelling system; and climate variations with records of wildfires and variation on the vegetation; in addition to records that could be related to human occupation.

Descrição Arquivo
COMPLETE  PDF
Logo maxwell Agora você pode usar seu login do SAU no Maxwell!!
Fechar Janela



* Esqueceu a senha:
Senha SAU, clique aqui
Senha Maxwell, clique aqui