Deformação, fluxo de fluidos e a formação de depositos auriferos na zona de cisalhamento de Itapetim, Provincia Borborema (NE do Brasil)

Orientadores : Roberto Perez Xavier, Peter Christian HackspacherTese (doutorado) - Universidade Estadual de Campinas, Instituto de GeocienciasDoutorad

U-Pb e Sm-Nd em Ortognaisses Riacianos e Estaterianos nos Terrenos Rio Piranhas-Seridó e Jaguaribeano, Província Borborema, Brasil

The Portalegre shear zone separates the Rio Piranhas-Seridó and the Jaguaribeano geological terranes in the Northern Domain of the Borborema Province. Banded gneisses of the Caicó and the Jaguaretama Complexes represent the basements of these terranes. U-Pb analyses yielded ages of 2,193 ± 16 Ma for the Jaguaretama Complex, which is similar to those obtained for the Caicó Complex. T DM Sm-Nd ages for these basement complexes showed Neoarchean values (ca. 2.5 Ga), with εNd(t) values close to the CHUR composition. Elongated bodies were found intruding into the rocks of the Jaguaretama Complex. These foliated bodies with elongated phenocrysts are described as augen gneisses of the Serra do Deserto Suite. These gneisses yielded crystallization ages of 1,777 ± 8 Ma, confirming an extensional period during the Statherian, which is well represented in the Jaguaribeano Terrane by A-type plutonic rocks. Augen gneisses with similar textures, the so called Poço da Cruz Suite, are found intruding the Caicó Complex in the Rio Piranhas-Seridó terrane; however, the ages found throughout the domain are predominantly Rhyacian (ca. 2.2 Ga) and present calc-alkaline affinities. These findings indicate that the augen gneisses, which are widely distributed in these two terranes, have different signatures and are temporally well separated. Furthermore, in agreement with previous geophysical data suggesting a division of terranes marked by the Portalegre Shear Zone, it also demonstrates that even though the Caicó and the Jaguaretama Complexes have similar ages, similar structural evolution and metamorphism under similar pressure and temperature conditions, they exhibit marked differences in composition.A zona de cisalhamento Portalegre separa os terrenos geológicos Rio Piranhas-Seridó e Jaguaribeano do Domínio Setentrional da Província Borborema, com gnaisses bandados dos Complexos Caicó e Jaguaretama representando os respectivos embasamentos destes terrenos. Análises U-Pb forneceram idades de 2.193 ± 16 Ma para os ortognaisses do Complexo Jaguaretama, resultados muito similares às determinadas para o Complexo Caicó. Idades T DM Sm-Nd nesses Complexos forneceram valores neoarqueanos (ca. 2,5 Ga), com εNd(t) muito próximos ao CHUR. Intrudindo as rochas do Complexo Jaguaretama, destacam-se corpos alongados, foliados e com pórfiros estirados, denominados de Suíte Serra do Deserto. Estes forneceram idades de cristalização a 1.777 ± 8 Ma, ratificando um período extensional que ocorreu no Estateriano, bem representado no terreno Jaguaribeano por sequências vulcanossedimentares e plutônicas Tipo-A. Augen gnaisses com texturas similares, denominados de Suíte Poço da Cruz, são encontrados intrudindo o Complexo Caicó no terreno Rio Piranhas-Seridó, porém, as idades registradas por todo este domínio são predominantemente Riacianas (ca. 2,2 Ga) e de afinidades cálcio-alcalinas, indicando que estes augen gnaisses possuem diferentes assinaturas e estão bem separados no tempo. Além disso, além dos dados geofísicos prévios que sugerem esta divisão de Terrenos marcada pela Zona de Cisalhamento Portalegre, os Complexos Caicó e Jaguaretama exibem diferenças composicionais marcantes. Corpos de anfibolitos alongados e concordantes a subconcordantes com o bandamento do Complexo Caicó e importante contribuição sedimentar na constituição do Complexo Jaguaretama com importantes intercalações de mármores são algumas destas diferenças

Fluid evolution from quartz veins in micaschists from the thermal aureole around the Acari batholith, Northeast Brazil

Os micaxistos que circundam o batólito granítico de Acari (idade ediacarana, 572 a 577 Ma) são caracterizados por elevada quantidade de veios de quartzo. Os veios são mais abundantes nas zonas metamórficas com temperaturas mais altas, que somadas àquelas de temperaturas mais baixas formam a auréola que envolve o batólito. Os veios analisados são provenientes das zonas da biotita + clorita + muscovita, biotita + granada, cordierita + andaluzita e cordierita + sillimanita. Grande parte das inclusões fluidas são bifásicas, porém as variedades trifásicas podem ser localmente observadas. As temperaturas de fusão do CO2 (TfCO2) variam de -62,6 a -56,7°C. As temperaturas eutéticas (Te) mostram valores médios de -30,8°C nas zonas da biotita + clorita + muscovita e biotita + granada e de -38,6°C nas zonas da cordierita + andaluzita e cordierita + sillimanita. As temperaturas de fusão do gelo (Tfgelo) são mais baixas nas zonas metamórficas de mais altas temperaturas. Os valores das modas são de -3,8, -5,5, -5,6 e -7,3°C, que correspondem respectivamente às zonas de biotita + clorita + muscovita, biotita + granada, cordierita + andaluzita e cordierita + sillimanita. Um fluido caracterizado pelo sistema H2O-NaCl (KCl)-MgCl2- FeCl2-CaCl2 é definido por: Tfgelo que varia de -1,9 a -32°C; presença de cubos de sal nas zonas da cordierita + andaluzita e cordierita + sillimanita; e Te registradas entre -16,5 e -59,1°C. Adicionalmente, foram obtidas temperaturas de homogeneização total que variaram entre 117 e 388°C para as inclusões fluidas aquosas primárias. Os resultados são consistentes com o aumento da salinidade dos fluidos aquosos ao longo da auréola, na direção do batólito.Micaschists that host the Acari batholith (Ediacaran age, 572 to 577 My) are characterized by a large number of quartz veins. The veins are more abundant in higher-temperature metamorphic zones and, together with lower metamorphic zones, form an aureole centered in the batholith. Most of the fluid inclusions are two-phase (H2O-CO2 and liquid/vapor), but three-phase varieties (liquid/vapor/salt cubes; liquid/liquid/vapor) occur locally. The analyzed veins come from the biotite + chlorite + muscovite, biotite + garnet, cordierite + andalusite, and cordierite + sillimanite metamorphic zones. CO2 melting temperatures (TmCO2) vary from -62.6 to -56.7°C, suggesting CH4 and/or N2. Eutectic temperatures (Te) in quartz veins show average values of -30.8°C in the biotite + chlorite + muscovite and biotite + garnet zones, and -38.6°C in the cordierite + andalusite and cordierite + sillimanite zones. Ice-melting temperatures (Tmice) are lower in the higher-temperature metamorphic zones. The mode values are -3.8, -5.5, -5.6, and -7.3°C, corresponding respectively to the biotite + chlorite + muscovite, biotite + garnet, cordierite + andalusite, and cordierite + sillimanite zones. A fluid characterized by the H2O-Na-Cl (KCl)-MgCl2-FeCl2-CaCl2 system is defined by: Tmice from near -1.9 to -32°C, the presence of salt cubes mainly in the cordierite + andalusite and cordierite + sillimanite zones, and recorded eutectic temperatures (Te) from -16.5 to -59.1°C. In addition, total homogenization temperatures (Tht) ranging from 117 to 388°C were obtained for primary aqueous fluid inclusions. This indicates a long period of fluid circulation under conditions of falling temperatures. Our results are consistent with an increase in the salinity of the aqueous fluid across the thermal aureole toward the granitic batholith

Crosstalk between biological and chemical diversity with cytotoxic and cytostatic effects of Aphanothece halophytica in vitro

Abstract Different solvent extracts from Aphanothece halophytica (A. halophytica) were evaluated for their cytotoxic effects against four human cancer cell lines. The samples demonstrated different percentages of cyanobacteria species populations. The samples containing 100% A. halophytica and 90% A. halophytica showed a significant cytotoxic effect in human breast cancer cells MDA231. The cytostatic effect was demonstrated in MDA231 and human glioblastoma T98G cells regardless of the treatment, resulting in a significant cell cycle arrest in the S phase. The chemical profiles of the extracts were proven to be diverse in qualitative and quantitative compositions. This variability was dependent on the A. halophytica´s abundance in each extract. The 100% A. halophytica extract induced cytotoxic and cytostatic effects in breast cancer cells, and those could be associated with the predominance of fatty acids, hydrocarbons and phthalates, indicating that A. halophytica is an interesting source of novel compound with anticancer effect

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

Núcleos de Ensino da Unesp: artigos 2008

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq