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A syenite body was discovered and studied in the Santa Catarina Granulitic Complex, close to the beaches of Grant and Barra Velha. The quarry, located on km·91 of BR-101 highway, was sampled for geochemical whole rock studies and also of its individual minerals. The syenite body is in structural and metamorphic equilibrium with the containing hypersthene-bearing tonalitic and basaltic granulites. Major, trace and rare-earth elements analyses on rock samples indicate syenitic to quartz dioritic compositions, saturated in alumina and silica. They have high contents of K, Na, Sr and Ba and low contents of Zr and Ti. Total REE is high in chondrite-normalized paterns and indicates strong fractionation of the light REE, similar to those for the Itiúba Syenite from Bahia State and for the Linden Syenite from Minnesota, USA. Overall geochemistry, on the other hand, is remarkably similar to the Archean Cléricy Pluton from Canada. The REE are strongly concentrated in allanite, clinopyroxene and sphene strongly. A Sm-Nd mineral isochron indicates metamorphic crystallization at ca. 2.2 Ga. The syenite is depleted in HFSE, and this may indicated a subduction-zone tectonic environment of generation of the magma. The foregoing results are based on 12 whole rock chemical analyses for major and some trace elements, three whole rock REE analyses, two electron microprobe analyses on each of seven minerals and Sm/Nd isotopic determinations on five minerals.

-The aim of this paper was to assess, in a study case, whether ash-fall deposition influenced the character of the peat-forming vegetation in some coal beds in the southernmost Paraná Basin in Brazil, taking into consideration that records of tonstein levels are common in some coal bearing-strata. An investigation was made of the uppermost Faxinal coal seam (Coal Seam S), which displays two adjacent coal beds interbedded with a tonstein level. On the basis of the botanical affinity between the miospores and the parent plants as well as the relative abundance of the different plant groups, each coal plant assemblage was determined. Furthermore, previous paleobotanical data obtained on the tonstein level that identified a compressed Glossopteris flora were incorporated in the study. Palynofacies analyses performed on both coal and tonstein levels demonstrated good results for the recognition of preserved organic matter and changes in paleoenvironmental conditions along the coal sequence. The effect of volcanic ash-fall deposition was reflected by changes in the character of the vegetation associated with coal layers below and above the tonstein. Palynofacies results corroborated palynological and paleobotanical interpretation and contributed to the establishment of the floral succession deposited over a short time interval, under the effect of volcanic ash-fall deposition.Key words: palynology, paleobotany, palynofacies, coal, tonstein, Paraná Basin.RESUMO -O trabalho objetivou avaliar o efeito da deposição de cinza vulcânica sobre o caráter da vegetação responsável pela formação de alguns carvões na jazida do Faxinal, levando em consideração que registros de tonstein são comuns em sequências de carvão na porção sul da bacia do Paraná, no Brasil. Em estudo de caso, foi analisada a camada de carvão superior (Camada S) que apresenta, na sua porção mais superior, dois leitos adjacentes de carvão intercalados por um nível de tonstein originado de cinza vulcânica. A composição das palinofloras foi determinada com base na afinidade dos esporos e dos grãos de pólen e na relação de freqüência dos diferentes grupos vegetais. Dados paleobotânicos anteriores desenvolvidos nesse nível de tonstein, que demonstraram a presença de uma importante Flora Glossopteris, foram incorporados ao trabalho aqui proposto. As análises de palinofácies produziram resultados significativos para o reconhecimento da matéria

ABSTRACT:The Piriá Basin (Piriá Formation) is a hemi-graben shaped basin that developed over Precambrian rocks of the Gurupi Belt. The lithological content comprises four interfingered lithofacies: (1) arkose and greywacke with pelite layers, (2) laminated siltstones and pelites, (3) arkose with hummocky stratification, and (4) oligomictic conglomerate. This sequence was formed in alluvial fans (conglomerate), and fluvial systems (arkose, greywacke, siltstones and pelites) that were established and evolved during the migration of the subsidence. The sedimentary sequence underwent anquimetamorphism and very weak tectonic deformation. U-Pb analyses of detrital zircon set the maximum depositional age at 591 Ma and indicate several sediment sources, that range in age from the Neoproterozoic to the Archean. The main sources are from the Rhyacian, which is the main period of continental crust formation in the São Luís cratonic fragment and the basement of the Gurupi Belt. Neoproterozoic sources were important in the eastern segment of the basin. Ages from unknown sources in the region so far have also been recorded. Combined, the U-Pb zircon data, the whole-rock geochemical and Sm-Nd results, and the petrographic information revealed proximal felsic to intermediate provenance, in addition to recycled sedimentary sources. As a whole, our data suggest that the Piriá Formation was deposited in a post-orogenic basin related to the final stage of evolution of the Brasiliano cycle of orogenies, which built up the Gurupi Belt. KEYWORDS:Brasiliano/Pan-african cycle; Provenance; Post-orogenic basins; Sedimentology; Gurupi Belt; São Luís craton. RESUMO:

A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença.Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra.Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso.Integration of geochronologic, paleobotanical and organic matter studies in gondwanan tonstein (Sakmarian, Paraná Basin, Brazil)