The Serido Group of NE Brazil, a late Neoproterozoic pre- to syn-collisional basin in West Gondwana: insights from SHRIMP U-Pb detrital zircon ages and Sm-Nd crustal residence (T-DM) ages

The Serido Group is a deformed and metamorphosed metasedimentary sequence that overlies early Paleoproterozoic to Archean basement of the Rio Grande do Norte domain in the Borborema Province of NE Brazil. The age of the Serido Group has been disputed over the past two decades, with preferred sedimentation ages being either Paleoproterozoic or Neoproterozoic. Most samples of the Serido Formation, the upper part of the Serido Group, have Sm-Nd T-DM ages between 1200 and 1600 Ma. Most samples of the Jucurutu Formation, the lower part of the Serido Group, have T-DM ages ranging from 1500 to 1600 Ma; some basal units have T-DM ages as old as 2600 Ma, reflecting proximal basement. Thus, based on Sm-Nd data, most, if not all, of the Serido Group was deposited after 1600 Ma and upper parts must be younger than 1200 Ma.Cathodoluminescence photos of detrital zircons show very small to no overgrowths produced during ca. 600 Ma Brasiliano deformation and metamorphism, so that SHRIMP and isotope dilution U-Pb ages must represent crystallization ages of the detrital zircons. Zircons from meta-arkose near the base of the Jucurutu Formation yield two groups of ages: ca. 2200 Ma and ca. 1800 Ma. In contrast, zircons from a metasedimentary gneiss higher in the Jucurutu Formation yield much younger ages, with clusters at ca. 1000 Ma and ca. 650 Ma. Zircons from metasedimentary and metatuffaceous units in the Serido Formation also yield ages primarily between 1000 and 650 Ma, with clusters at 950-1000, 800, 750, and 650 Ma. Thus, most, if not all, of the Serido Group must be younger than 650 Ma. Because these units were deformed and metamorphosed in the ca. 600 Ma Brasiliano fold belt during assembly of West Gondwana, deposition probably occurred ca. 610-650 Ma, soon after crystallization of the youngest population of zircons and before or during the onset of Brasiliano deformation.The Serido Group was deposited upon Paleoproterozoic basement in a basin receiving detritus from a variety of sources. The Jucurutu Formation includes some basal volcanic rocks and initially received detritus from proximal 2.2-2.0 Ga (Transamazonian) to late Paleoproterozoic (1.8-1.7 Ga) basement. Provenance for the upper Jucurutu Formation and all of the Serido Formation was dominated by more distal and younger sources ranging in age from 1000 to 650 Ma. We suggest that the Serido basin may have developed as the result of late Neoproterozoic extension of a pre-existing continental basement, with formation of small marine basins that were largely floored by cratonic basement (subjacent oceanic crust has not yet been found). Immature sediment was initially derived from surrounding land; as the basin evolved much of the detritus probably came from highlands to the south (present coordinates). Alternatively, if the Patos shear zone is a major terrane boundary, the basin may have formed as an early collisional foredeep associated with south-dipping subduction. In any case, within 30 million years the region was compressed, deformed, and metamorphosed during final assembly of West Gondwana and formation of the Brasiliano-Pan African fold belts. (C) 2003 Elsevier B.V. All rights reserved.

Pareto Frontier for the time-energy cost vector to an Earth-Moon transfer orbit using the patched-conic approximation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fission track and U-Pb in situ dating applied to detrital zircon from the Vale do Rio do Peixe Formation, Bauru Group, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

From Amazonia to the Atlantic forest: Molecular phylogeny of Phyzelaphryninae frogs reveals unexpected diversity and a striking biogeographic pattern emphasizing conservation challenges

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Optimization of satellite constellations in the moon

Nowadays, we return to live a period of lunar exploration. China, Japan and India heavily invest in missions to the moon, and then try to implement manned bases on this satellite. These bases must be installed in polar regions due to the apparent existence of water. Therefore, the study of the feasibility of satellite constellations for navigation, control and communication recovers importance. The Moon's gravitational potential and resonant movements due to the proximity to Earth as the Kozai-Lidov resonance, must be considered in addition to other perturbations of lesser magnitude. The usual satellite constellations provide, as a basic feature, continuous and global coverage of the Earth. With this goal, they are designed for the smallest number of objects possible to perform a specific task and this amount is directly related to the altitude of the orbits and visual abilities of the members of the constellation. However the problem is different when the area to be covered is reduced to a given zone. The required number of space objects can be reduced. Furthermore, depending on the mission requirements it may be not necessary to provide continuous coverage. Taking into account the possibility of setting up a constellation that covers a specific region of the Moon on a non-continuous base, in this study we seek a criterion of optimization related to the time between visits. The propagation of the orbits of objects in the constellation in conjunction with the coverage constraints, provide information on the periods of time in which points of the surface are covered by a satellite, and time intervals in which they are not. So we minimize the time between visits considering several sets of possible constellations and using genetic algorithms.

Livros didáticos de física para o ensino médio: uma análise de conteúdo das práticas de eletricidade e magnetismo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O cálculo e a invenção na poética de Stockhausen

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Notas de testemunho e recalque: uma experiência musical dos traumas sociais brasileiros em Chico Buarque e Paulinho da Viola (de meados da década de 1960 a meados da década de 1970)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O longo caminho: guerreiro ramos e a sociologia da administração antes de a nova ciência das organizações

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Autogenous bone grafts contamination after exposure to the oral cavity

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tecnologias de Informação e Comunicação (TICs) e literatura, uma aposta notável

The aim of this study was to develop a qualitative research of bibliographic nature, in order to verify how has been the use of new Information and Communication Technologies (ICTs) and literary reading in early childhood education.. It is believed to be necessary for children, since their early childhood, to, be in contact with various literary works of aesthetic value, which will enable them to understand this particular literary language - and the imagery that comes with it - what can instigate appreciate literature and get the reading habit. The use of ICTs by children beyond the use of games and watching stories on computers, tablets and smartphones, for example, for the production of videos and slides or creating stories, enable new experiences of redesigning and construction of knowledge and culture. The idea for this research came from reading the numerous texts that deal with the need to understand the child as an active subject in the construction of culture and society, rather than as receiving reproductive and cultural orders (CRIANÇAS, 2012). In this sense, in addition to the newsletters Equity For Children: Latin America (CRIANÇAS, 2012), the understanding of childhood and child in the works of Walter O. Kohan (2005; 2006) supports this study. This research proposal was also based on authors and documents that point to the need to promote, since the first stages of Basic Education, the literary reading as a means of enjoyment and emancipation (LAJOLO 2001a; Barthes, 2007; FILIPOUSKY, 2009; BRAZIL, 2010; MACHADO, 2011; VASQUES, 2013), and an education connected to the technological advances of the twenty-first century (BRAZIL, 1997, CHAVES, 1998; DEMO, 2008)