Isotope Dating
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Vegetation and climate changes in the forest of Campinas, São Paulo State, Brazil, during the last 25,000 cal yr BP
Abstract A paleoenvironmental reconstruction was performed in a Riparian Forest near Campinas to improve knowledge of paleoclimate and paleoenvironment in the State of São Paulo, Brazil. A sediment core of 182 cm depth was collected in a swamp located within a Cerrado/Seasonal Semi-deciduous ecotone forest. The chronological frame is given by eight radiocar
Braz. J. Geol.. Publicado em: 10/10/2019
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2. Relationships of stable isotopes, water-rock interaction and salinization in fractured aquifers, Petrolina region, Pernambuco State, Brazil
Abstract The Petrolina County, Pernambuco State, Brazil, presents specificities that make it unique from a hydrogeological point of view. Water resource scarcity is both a quantitative and qualitative issue. The climate is classified as semiarid, having low precipitation, along with high temperatures and evapotranspiration rates. Aquifer zones are related to
REM, Int. Eng. J.. Publicado em: 2018-03
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3. Reconstrução da vegetação e do clima em alta resolução no Holoceno na Ilha do Marajó, com o uso de indicadores biológicos e isotópicos / Reconstruction of vegetation and climate in high resolution at Holocene on Marajo Island, with biologic and isotopic indicators uses
Um estudo interdisciplinar, envolvendo análises de fácies, elementares e isotópicas de carbono e nitrogênio, palinologia e diatomáceas, teve como objetivo reconstruir a dinâmica da vegetação, na Ilha do Marajó, com inferências climáticas. Testemunhos sedimentares foram coletados em dois pontos diferentes na porção leste da Ilha, um no manguezal
Publicado em: 2011
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4. Contribuição à paleoecologia da Amazônia Meridional na planície de inundação do Rio Teles Pires, do norte do Estado do Mato Grosso
Records of isotopic and elemental carbon and nitrogen and pollen in lake sediments and soils have been used for studies of Quaternary paleoecology worldwide, including in the Amazon at specific sites, such as the region of Carajas, Lake Pata and Region Porto Velho in Rondonia state making it necessary to register in the central southern region. We collected
Publicado em: 2010
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5. Evolução tectono-estratigráfica e paleoclimática da formação maricá (Escudo Sul-Rio-Grandense, Brasil) : um exercício de geologia histórica e análise integrada de uma bacia sedimentar neoproterozóica
Significant improvement in the knowledge concerning the Neoproterozoic Maricá Formation of the Sul-riograndense Shield, southern Brazil, was obtained in the latest years. This contribution synthesizes recent data obtained though an integrated analysis of the lowermost unit of the “Camaquã Basin”. Stratigraphic and paleocurrent analyses, petrography, Sr
Publicado em: 2010
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6. A unidade Maria Preta : geologia, geoquimica e petrogenese de rochas vulcanicas e sub-vulcanicas intermediarais a felsicas no "Greenstone Belt" do rio Itapicuru, Bahia / The Maria Preta unit : geology, geochemistry and petrogenesis of volcanic and sub-volcanic intermediate to felsic rocks in the Rio Itapicuru greenstone belt, Bahia
New geochemical data on andesites and dacites of the Maria Preta Unit, Rio Itapicuru Greenstone Belt, revealed two distinct geochemical groups: one of adakitic affinity and another of typical calc-alkaline. The adakitic suite, localized west in the unit, is characterized by high values of Sr/Y and Ti/YN >1. It shows enrichment in LFSE (Low Field Strength Ele
Publicado em: 2008
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7. Estudos arqueométricos de sítios arqueológicos do baixo São Francisco / Archaeometrics studies of archaeological sites from Baixo São Francisco
O estudo minucioso das características físicas e químicas dos artefatos cerâmicos, associado com as pesquisas históricas e arqueológicas tem pennitido a reconstituição dos costumes culturais e modos de vida das comunidades antigas. O presente estudo objetivou estudar composição química elementar e mineralógica de cerâmicas arqueológicas coletad
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/02/2007
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8. Uranium-lead dating method at the Pará-Iso isotope geology laboratory, UFPA, Belém - Brazil
Os procedimentos analíticos para análises U-Pb por diluição isotópica no Laboratório de Geologia Isotópica (Pará-Iso) da Universidade Federal do Pará (UFPA) são descritos detalhadamente. Esses procedimentos são aplicados para análises de zircão, titanita, rutilo, apatita, columbita-tantalita e rocha total. A purificação dos reagentes e os proc
Anais da Academia Brasileira de Ciências. Publicado em: 2007-03
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9. Metodologia de datação em carbonatos pela série de desequilíbrio do urânio por espectrometria de massa
There are many dating methods largely used according to the kind of material to be dated. Methods that rely on the time-dependency of geochemical disequilibrium 238 235 232 U, U and Th natural decay system, between daughter and parent isotope, from the whose final members are stable Pb isotopes, are the most useful in a broader variety of geological, hydrolo
Publicado em: 2006
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10. Estudos geoquimicos e isotopicos das mineralizações auriferas e rochas associadas da Região de Pontes e Lacerda (MT)
Geochemistry and isotope studies were carried out on the gold deposits of Pontes e Lacerda region (Mato Grosso state, Brazil) where rocks of the Aguapei and Rondoniense mobile belts (SW of Amazon Craton) occur. The stratigraphy of this part of Amazon Craton consists of the Pontes e Lacerda Metavulcano-sedimentar Sequence (PLMVSS), Santa Helena Granite-Gneiss
Publicado em: 1996
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11. Stable isotope evidence for increasing dietary breadth in the European mid-Upper Paleolithic
New carbon and nitrogen stable isotope values for human remains dating to the mid-Upper Paleolithic in Europe indicate significant amounts of aquatic (fish, mollusks, and/or birds) foods in some of their diets. Most of this evidence points to exploitation of inland freshwater aquatic resources in particular. By contrast, European Neandertal collagen car
The National Academy of Sciences.
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12. Variation in Ginkgo biloba L. leaf characters across a climatic gradient in China
Fossil leaves assigned to the genus Ginkgo are increasingly being used to reconstruct Mesozoic and Tertiary environments based on their stomatal and carbon isotopic characteristics. We sought to provide a more secure basis for understanding variations seen in the plant fossil record by determining the natural variability of these properties of sun and sh
National Academy of Sciences.