Mapeamento geológico no alvo Morro do Corcunda - Greenstone Belt Pilar de Goiás (Santa Terezinha-GO)

The following work refers to a geologic mapping in the Morro do Corcunda target, located between the cities of Pilar of Goiás and Santa Terezinha in the northwest portion of the State of Goiás. This mapping was carried through in 1:10,000 scale and covers an area of approximately 60km2. Collections of samples had been carried through for laborarorial analysis, and from those twenty-three thin scetions have been produced in order to describe the main lithologies that occur in the area. It was possible to observe anomalous gold targets in the region through chip samples carried through during the stage of field work. The gathered field data and the ones that have been made available by the company Yamana Gold Incorporation were congregated, and a data integration was carried through. This integration made possible the correlation of the litologies found in field with the Greenstone Belt Pilar de Goiás sequence and the structural evolution of the area.

Análise estrutural e microtectônica da inflexão do jordino e depósitos de ouro associados no greenstone belt de Pilar de Goiás

The study area is included in the geological context of the Goias Median Massif, a region where there are associations of Archean granite-gneiss complex (Block Moquém) and a Paleoproterozoic metavolcano-sedimentary sequence ( Pilar greenstone belt ). At the south of area, the greenstone sequence is partially overlain by Neopreoterozoic metasediments of the Araxá Group. The lithostratigraphic units of the Pilar greenstone belt define a shift from about N30W direction (north of the deposit) to N60 and 70W in the region south of the Jordino deposit, where are truncated by the Araxá Group rocks. Mineralogical associations described in this paper allow to indicate that the regional metamorphism that affected the rocks of the greenstone belt and Araxá Group, in the mapped area, reached the upper greenschist facies (garnet zone). Data obtained during mapping and by microtectonics analysis allow to indicate the existence of at least four deformational events that acted on the rocks of the Guarinos greenstone belt and Araxá Group, represented by the phases called Dn-1, Dn, Dn + 1 and Dn+2. It was observed that the pattern of sulphide porfitoblasts in mineralized levels is similar to garnet, biotite and muscovite porfiroblasts (tardi to post Dn) that marks the metamorphic peak of the area

Prospecção mineral de alvos potenciais à ocorrência de enriquecimento supergênico de níquel no Greenstone belt do Morro do Ferro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Geologia do depósito de ouro de C1-Santaluz no greenstone belt do rio Itapicuru, Brasil

Pós-graduação em Geociências e Meio Ambiente - IGCE

Construcción de repositorios institucionales open source con Software Greenstone

Se aborda la construcción de repositorios institucionales open source con Software Greenstone. Se realiza un recorrido teórico y otro modélico desarrollando en él una aplicación práctica. El primer recorrido, que constituye el marco teórico, comprende una descripción, de: la filosofía open access (acceso abierto) y open source (código abierto) para la creación de repositorios institucionales. También abarca en líneas generales las temáticas relacionadas al protocolo OAI, el marco legal en lo que hace a la propiedad intelectual, las licencias y una aproximación a los metadatos. En el mismo recorrido se abordan aspectos teóricos de los repositorios institucionales: acepciones, beneficios, tipos, componentes intervinientes, herramientas open source para la creación de repositorios, descripción de las herramientas y finalmente, la descripción ampliada del Software Greenstone; elegido para el desarrollo modélico del repositorio institucional colocado en un demostrativo digital. El segundo recorrido, correspondiente al desarrollo modélico, incluye por un lado el modelo en sí del repositorio con el Software Greenstone; detallándose aquí uno a uno los componentes que lo conforman. Es el insumo teórico-práctico para el diseño -paso a paso- del repositorio institucional. Por otro lado, se incluye el resultado de la modelización, es decir el repositorio creado, el cual es exportado en entorno web a un soporte digital para su visibilización. El diseño del repositorio, paso a paso, constituye el núcleo sustantivo de aportes de este trabajo de tesina

Construcción de repositorios institucionales open source con Software Greenstone

Se aborda la construcción de repositorios institucionales open source con Software Greenstone. Se realiza un recorrido teórico y otro modélico desarrollando en él una aplicación práctica. El primer recorrido, que constituye el marco teórico, comprende una descripción, de: la filosofía open access (acceso abierto) y open source (código abierto) para la creación de repositorios institucionales. También abarca en líneas generales las temáticas relacionadas al protocolo OAI, el marco legal en lo que hace a la propiedad intelectual, las licencias y una aproximación a los metadatos. En el mismo recorrido se abordan aspectos teóricos de los repositorios institucionales: acepciones, beneficios, tipos, componentes intervinientes, herramientas open source para la creación de repositorios, descripción de las herramientas y finalmente, la descripción ampliada del Software Greenstone; elegido para el desarrollo modélico del repositorio institucional colocado en un demostrativo digital. El segundo recorrido, correspondiente al desarrollo modélico, incluye por un lado el modelo en sí del repositorio con el Software Greenstone; detallándose aquí uno a uno los componentes que lo conforman. Es el insumo teórico-práctico para el diseño -paso a paso- del repositorio institucional. Por otro lado, se incluye el resultado de la modelización, es decir el repositorio creado, el cual es exportado en entorno web a un soporte digital para su visibilización. El diseño del repositorio, paso a paso, constituye el núcleo sustantivo de aportes de este trabajo de tesina

The greenstone schist areas of the Menominee and Marquette regions of Michigan; a contribution to the subject of dynamic metamorphism in eruptive rocks,

Mode of access: Internet.

Pounamu, notes on New Zealand greenstone,

Mode of access: Internet.

Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland

The oldest known bona fide succession of elastic metasediments Occurs in the Isua Greenstone Belt. SW Greenland and consists of a variety of mica schists and rare metaconglomerates. The metasediments are in direct contact with a felsic metavolcanic lithology that has previously been dated to 3.71 Ga. Based on trace element geochemical data for 30 metasediments, we selected the six samples with highest Zr concentrations for zircon extraction. These samples all yielded very few or no zircon, Those extracted from mica schists yielded ion probe U/Pb ages between 3.70 and 3,71 Ga. One metaconglomerate sample yielded just a single zircon of 3.74 Ga age. The mica schist hosted zircons have U/Pb ages. Th/U ratios, REE patterns and Eu anomalies indistinguishable from zircon in the adjacent 3.71 Ga felsic metavolcanic unit. Trace element modelling requires the bulk of material in the metasediments to be derived from variably weathered mafic lithologies but some metasediments contain substantial contribution from more evolved source lithologies. The paucity of zircon in the mica schists is thus explained by incorporation of material from largely zircon-free volcanic lithologies. The absence of older zircon in the mica schists and the preponderance of mafic source material imply intense, mainly basaltic resurfacing of the early Earth. The implications of this process are discussed, Thermal considerations suggest that horizontal growth of Hadean crust by addition of mafic ultramafic lavas must have triggered self-reorganisation of the protocrust by remelting. Reworking oft Hadean crust may have been aided by burial of hydrated (weathered) metabasalt due to semi-continuous addition of new voluminous basalt Outpouring,;, This process Causes a bias towards eruption of Zr-saturated partial melts at the surface with O-isotope corn posit ion,, potentially different from the mantle. The oldest zircons hosted in sediments would have been buried to substantial depth or formed in plutons that crystallised at some depth from which it took hundreds of millions of years for them to be exhumed and incorporated into much younger sediments. (C) 2005 Elsevier B.V.All rights reserved.

Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland

New and published major and trace element abundances of elastic metasediments (mainly garnet-biotite-plagioclase schists) from the similar to 3.8 Ga Isua Greenstone Belt (IGB), southern West Greenland, are used in an attempt to identify the compositional characteristics of the protoliths of these sediments. Compositionally, the metasediments are heterogeneous with enrichment of LREE (La/Sm-chord = 1.1-3.9) and variable enrichment and depletion of HREE (Gd/Yb-chord = 0.8-4.3). Chondrite-normalized Eu is also variable, spanning a range from relative Eu depletion to enrichment (Eu/Eu* = 0.6-1.3). A series of geochemical and geological criteria provides conclusive evidence for a sedimentary origin, in disagreement with some previous studies that questioned the presence of genuine elastic metasediments. In particular, trace element systematics of IGB metasediments show strong resemblance to other well-documented Archaean clastic sediments, and are consistent with a provenance consisting of ultramafic, malic and felsic igneous rocks. Two schists, identified as metasomatized mafic igneous rocks from petrographic and field evidence, show distinct compositional differences to the metasediments. Major element systematics document incipient-to-moderate source weathering in the majority of metasediments, while signs of secondary K-addition are rare. Detailed inspection of Eu/Eu*, Fe2O3 and CIW (chemical index of weathering) relationships reveals that elevated iron contents (when compared to averages for continental crust) and strong relative enrichment in Eu may be due to precipitation of marine Fe-oxyhydroxides during deposition or diagenesis on the seafloor. Some of the IGB metasediments have yielded anomalous Nd-142 and W-182 isotopic compositions that were respectively interpreted in terms of early mantle differentiation processes and the presence of a meteorite component. Alternatively, W and possibly Nd isotopes could have been affected by thermal neutron capture on the Hadean surface. The latter process was tested in this study by analysis of Sm isotope compositions, which serve as an effective monitor for neutron capture effects. As no anomalous variation from terrestrial values was detected, we infer that isotope systematics (including W-182 and Nd-142) of IGB metasediments were not affected by neutron capture, but reflect decay of radioactive parent isotopes. Copyright (c) 2005 Elsevier Ltd.

Petrografia, geoquímica e geocronologia das rochas metavulcânicas e metaplutônicas dos Greenstone Belts faina e Serra de Santa Rita : implicações para o ambiente tectônico

Dissertação (mestrado)—Universidade de Brasília, Instituto de Geociências, Pós-Graduação em Geologia, 2016.