Recent work in the Melville Peninsula area of the Rae Craton provides new constraints on the lithotectonic framework of Archean supracrustal rocks and associated Archean intrusions, as well as Paleoproterozoic cover sequences. The region is subdivided into four
lithologically distinctive crustal blocks that include from north to south: the Northern Granulite Block; the Prince Albert Block; on which lies the Penrhyn Group; and the Repulse Bay Block. The Prince Albert belt is redefined as a ca. 3.20 Ga to 2.77 Ga greenstone belt, much older than the
Committee Bay belt to which it was historically linked and collectively named the Prince Albert Group. On the eastern side of the Peninsula, the Roche Bay greenstone belt appears to be linked - at least in age - to the Prince Albert belt. Penetrative Paleoproterozoic deformation can be confidently
documented northwesterly to the Roche Bay greenstone belt. Beyond this, it is less well defined although the Folster Lake Formation suggests moderate deformation under upper-greenschist metamorphic conditions.
A análise morfossedimentar do sistema praia-antepraia-plataforma continental interna objetiva caracterizar e identificar os processos hidrodinâmicos e morfossedimentares atuantes no referido sistema e analisar mais detalhadamente a aplicação do conceito de perfil de equilíbrio (Dean 1977). É avaliada a hipótese de que o recobrimento sedimentar na antepraia não controla a forma do perfil de equilíbrio, sendo o substrato reliquiar da antepraia o dominador de tal formato. Análises histórico-geomorfológicas, oceanográficas e sedimentológicas da área e observações de campo permitiram avaliar a estabilidade da linha de costa na faixa costeira do Parque Nacional da Restinga de Jurubatiba - Rio de Janeiro. A forte erosão observada na praia manifestou-se de maneira pontual, consequência de variações de: altura das ondas, principalmente de sul, sudoeste e sul-sudoeste; sedimentos finos e lamosos na antepraia e na plataforma continental interna e orientação da linha de costa. O estado morfodinâmico refletivo da praia e a presença de areia muito fina e lama na antepraia dificultam o deslocamento transversal dos sedimentos, incumbindo a deriva litorânea do papel principal de manutenção do material grosso neste sistema. O histórico geológico-geomorfológico transgressivo da área favorece também uma maior instabilidade deste litoral. Os desequilíbrios morfológicos observados na praia são compensados pelo grande volume de sedimentos mobilizados pela corrente longitudinal de sentido sudoeste-nordeste. A aparente estabilidade desta praia pode estar comprometida caso ocorram alterações do padrão de ondas, como, por exemplo, a intensificação das frentes frias, e/ou, cesse ou seja reduzido o trânsito longitudinal de sedimentos
Marine insertion indicators in the Vitoria estuary (ES) revealed relative variations in sea level during the Holocene in three sediment cores. Sedimentological, geochemical (C/N ratio), and paleontological (shells and palynomorphs) analysis and 14C dating associated five sedimentary facies to different estuarine deposits. A C/N ratio <10 at the core base indicated organic matter of marine origin. Moving up the cores to 110–150 cm, an abrupt increase in C/N to 26–63 in every core suggests the sudden entry of higher plants into the estuary, potentially the moment sea level retreated. High continental (10,743 palynomorphs/g) and low marine palynomorph concentrations (323 palynomorphs/g) suggest a primarily continental source even during transgression and at high sea level. Around 8973 cal BP, an open bay already existed in the region of Vitoria. Sea level potentially exceeded the current level around 7110 cal BP. The transgressive maximum was at 5567 cal BP. Marine insertion indicators, such as marine shells, low C/N ratios and foraminiferal linings, did not always respond directly to sea level oscillations. These discrepancies probably result from lateral variations in sedimentary deposits from transport patterns and from variations in organic matter and palynomorph preservation due to differences in river and obstacle proximity.
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