250 resultados para Paleontologia - Pleistoceno
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In this paper we analyze the set of Bronze Age bone tools recovered at the archaeological site of El Portalón of Cueva Mayor in the Sierra de Atapuerca (Burgos). The Bronze Age cultural period is the best represented in the cavity and its study has forced us to unify the different excavation and stratigraphical criteria undertaken from the earliest archaeological excavations developed by J.M. Apellániz during the 70s until the excavations of the current research team (EIA) since 2000. We propose here for the first time a relationship between the initial system of “beds” used by Apellániz and our recent sedimentary sequence that recognizes eleven stratigraphic levels radiometrically dated from the late Upper Pleistocene to the Middle Age. Within the bone industry assemblage we recognize a large variety of utensils and ornamental elements, with native and allochthonous features, that make evident a regional as well as long distance relationships of these populations of the interior of the Iberian Peninsula during the recent Prehistory.
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22 p.
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257 p.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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O Algar da Manga Larga tem-se revelado uma das mais importantes cavidades verticais em Portugal e, apesar de ser já conhecido pelos espeleólogos desde há mais de trinta anos, continua a fornecer dados com relevante significado científico. No decurso de uma acção de pesquisa espeleológica promovida pela AESDA no referido Algar foi fotografado um conjunto de ossos de carnívoro, jacentes numa galeria a cerca de 95 metros abaixo da entrada da cavidade. As respectivas características morfológicas e biométricas indicavam tratar-se de um grande felídeo, remetendo para espécie actualmente extinta na Europa, nomeadamente o leopardo, Panthera pardus (L., 1758). A evidente importância paleontológica dos testemunhos ósseos levou a que se desencadeasse um conjunto de procedimentos com o objectivo de os salvaguardar adequadamente e de promover o seu estudo. Para esse efeito, realizaram-se os contactos necessários e procedeu-se ao registo e à recolha das peças em apreço atribuindo especial atenção à sua integridade e conservação. Seguiram-se as tarefas ligadas ao estudo biométrico comparativo dos restos osteológicos. A presença deste e outros vestígios faunísticos, nomeadamente de gato-bravo, em zonas profundas e de difícil acesso desta gruta, indiciam a existência de condutas que estão ou estiveram em contacto com o meio exterior, as quais não foram ainda referenciadas. Deste modo, para além do evidente interesse paleontológico da descoberta, é possível serem extrapoladas interpretações com aplicação no âmbito da exegese da própria cavidade, situação que levou já à descoberta de uma galeria não registada. Este trabalho tem vindo a ser amplamente divulgado junto da comunidade espeleológica nacional e internacional, inclusivamente no 14º Congresso Internacional de Espeleologia que se realizou em 2005 na Grécia. O estudo paleontológico está concluído e a aguardar publicação em revista da especialidade (CARDOSO & REGALA, no prelo).
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ICHNOFOSSILS (PALEO-BURROWS and CROTOVINES) ATTRIBUTED TO EXTINCT MAMMALS IN SOUTHEASTERN and SOUTH BRAZIL. This work presents information regarding tunnels which are attributed to large extinct mammals. These structures can be found in several places in southeastern and southern Brazil, in different types of substrate, occurring as hollow structures (paleo-burrows) or those filled with sediments (crotovines). The dimensions and osteoderm and claw imprints found along the internal walls of the paleo-burrow found on aluvial fan deposits near the town of Cristal (Rio Grande do Sul State) suggest that a dasypodid xenarthran might have dug this structure. Comparison with similar structures found in Argentina can provide more detailed information regarding the paleoecology and biostratigraphy of the organisms that made these burrows.
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Tese de doutoramento em Paleontologia. Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2005
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Tese (doutorado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Animal, 2016.
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Evaluating the nature of the earliest, often controversial, traces of life in the geological record (dating to the Palaeoarchaean, up to ~3.5 billion years before the present) is of fundamental relevance for placing constraints on the potential that life emerged on Mars at approximately the same time (the Noachian period). In their earliest histories, the two planets shared many palaeoenvironmental similarities, before the surface of Mars rapidly became inhospitable to life as we know it. Multi-scalar, multi-modal analyses of fossiliferous rocks from the Barberton greenstone belt of South Africa and the East Pilbara terrane of Western Australia are a window onto primitive prokaryotic ecoystems. Complementary petrographic, morphological, (bio)geochemical and nanostructural analyses of chert horizons and the carbonaceous material within using a wide range of techniques – including optical microscopy, SEM-EDS, Raman spectroscopy, PIXE, µCT, laser ablation ICP-MS, high-resolution TEM-based analytical techniques and secondary ion mass spectrometry – can characterise, at scales from macroscopic to nanoscopic, the fossilised biomes of the earliest Earth. These approaches enable the definition of the palaeoenvironments, and potentially metabolic networks, preserved in ancient rocks. Modifying these protocols is necessary for Martian exploration using rovers, since the range and power of space instrumentation is significantly reduced relative to terrestrial laboratories. Understanding the crucial observations possible using highly complementary rover-based payloads is therefore critical in scientific protocols aiming to detect traces of life on Mars.
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This PhD thesis explores the ecological responses of bird species to glacial-interglacial transitions during the late Quaternary in the Western Palearctic, using multiple approaches and at different scales, enhancing the importance of the bird fossil record and quantitative methods to elucidate biotic trends in relation to long-term climate changes. The taxonomic and taphonomic analyses of the avian fossil assemblages from four Italian Middle and Upper Pleistocene sedimentary successions (Grotta del Cavallo, Grotta di Fumane, Grotta di Castelcivita, and Grotta di Uluzzo C) allowed us to reconstruct local-scale patterns in birds’ response to climate changes. These bird assemblages are characterized by the presence of temperate species and by the occasional presence of cold-dwelling species during glacials, related to range shifts. These local patterns are supported by those identified at the continental scale. In this respect, I mapped the present-day and LGM climatic envelopes of species with different climatic requirements. The results show a substantial stability in the range of temperate species and pronounced changes in the range of cold-dwelling species, supported by their fossil records. Therefore, the responses to climate oscillations are highly related to the thermal niches of investigated species. I also clarified the dynamics of the presence of boreal and arctic bird species in Mediterranean Europe, due to southern range shifts, during the glacial phases. After a reassessment of the reliability of the existing fossil evidence, I show that this phenomenon is not as common as previously thought, with important implications for the paleoclimatic and paleoenvironmental significance of the targeted species. I have also been able to explore the potential of multivariate and rarefaction methods in the analyses of avian fossils from Grotta del Cavallo. These approaches helped to delineate the main drivers of taphonomic damages and the dynamics of species diversity in relation to climate-driven paleoenvironmental changes.