Water mass reconstruction by Nd isotopic analysis from Mid Atlantic oceanic sediments

• Main Author: Ferreira, maria Luiza de Carvalho
• Other Authors: Universidade Estadual Paulista (UNESP)
• Format: Bachelor Thesis
• Language: English
• Published: Universidade Estadual Paulista (Unesp) 2013
• Subjects: Geologia estratigráfica; Espectrometria de massa; Sedimentos marinhos; Neodímio - Isótopos; Atlantico; Oceano; North Atlantic
• Online Access: http://hdl.handle.net/11449/119049

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Nd isotopic information obtained of Fe-Mn oxyhydroxide coatings marine sediment is used to reconstruct the interplay of water masses in the Mid Atlantic Ocean during the past 22 ka. The method consist of leaching those coatings and measure in Mass Spectrometer to define the εNd values (ε notion that compare the ratio 143Nd/144Nd in terms of their deviation from the Chondritic Uniform Resevoir (CHUR) evolution line) correspondent to past bottom sea water. The radiogenic or unradiogenic parameter of waters with Southern and Northern source (SSW and NSW) was captured for the sediments coating and is used to identify their influence in the surrounded area of the studied core at 22 000 years until present. The core is localized in Mid Atlantic Ocean and was collected in the IODP program in site 306 core U1313. The results had presented convinced records, giving evidence that during Holocene deep waters did not experience distinguished changes; the influence of NSW indicating a reduce but not the shutdown of deep water formation in North Atlantic during LGM; and the record data suggest possible contributions of eastern water mass into Mid Atlantic during glacial time Informações isotópicas de Nd obtidas da capa oxidada ferromanganífera de sedimentos marinhos são usadas para reconstruir a interação de massas de água no Oceano Atlântico Médio durante os últimos 22 ka. O método consiste na proxy εNd aplicada nos sedimentos, que consistem em dissolução destes revestimentos com o intuito de isolar o isótopo de Nd, posteriormente medições em espectrômetro de massa são feitas para definir os valores εNd (ε notação que compara ao razão dos isótopos 143Nd/144Nd em termos do seu desvio a partir da linha de evolução do “Chondritic Uniform Resevoir” (CHUR)) correspondentes a porção inferior das águas marinhas do passado. O caráter radioativo ou não radioativo de Águas Originárias do Sul e do Norte (SSW e NSW) foi capturado nestes revestimentos dos sedimentos ...