Efeito do tipo de substrato para pupação na dispersão larval pós-alimentar de Chrysomya albiceps (Diptera, Calliphoridae)

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

Geoelectrical mapping of contamination in the cemeteries: the case study in Piracicaba, São Paulo/Brazil

This paper presents the results of electrical resistivity methods in the area delineation that was potentially contaminated by liquefaction products, which are also called putrefactive liquids in Vila Rezende municipal cemetery, Piracicaba, So Paulo, Brazil. The results indicate a depth of water table between 3.1 and 5.1 m, with two groundwater direction flows, one to the SW and another to the SE. Due to the contamination plumes, which have the same groundwater direction flow, as well the conductive anomalies observed in the geoelectric sections, the contamination suspicions in the area were confirmed. The probable plume to the SE extends beyond the limits of the cemetery. The location of the conductive anomalies and the probable contamination plumes showed that the contamination is linked with the depth of the water table and the burial time. Mapping using the geostatistical method of ordinary kriging applied to the work drew structural characteristics of the regional phenomenon and spatial behavior of the electrical resistivity data, resulting in continued surfaces. Thus, this method has proved to be an important tool for mapping contamination plumes in cemeteries.

Carbonate cements in contemporaneous beachrocks, Jaguaribe beach, Itamaracá island, northeastern Brazil: petrographic, geochemical and isotopic aspects

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

Emprego do método da eletrorresistividade no estudo da contaminação subterrânea do cemitério municipal de Vila Rezende, Piracicaba - SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização petrográfica e aspectos diagenéticos dos arenitos do Grupo Bauru na região sudoeste do Estado de São Paulo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pennsylvanian Pteriomorphian bivalves from the Piaui Formation, Parnaiba Basin, Brazil

Dolostones of the upper Piaui Formation, Parnaiba Basin, northern Brazil, preserve a rich and diversified invertebrate fauna of Morrowan to Desmoinesian age. Among bivalves, Heteroconchia (15 species) is the most diversified, followed by Pteriomorphia (11 species), and rare endobenthic species of the Palaeotaxodonta. (three species). Eleven species of Pteriomorphia are described, including representatives of the genera Parallelodon?, Myalina?, Septimyalina, Caneyella?, Leptodesma (Leptodesma), L. (Leiopteria), Meekopinna?, Aviculopinna?, and Aviculopecten. A new combination, Etheripecten trichotomus, and the oldest member of the Anomiidae recorded, Pindorama nordestina n. gen. and sp., also are described. Details of muscle scars and hinge characters have been recovered for several taxa, thereby refining the knowledge for species diagnoses. Fossil beds in the Esperanca and Mucambo dolostones reveal episodic burial of bivalves in life position. These are internally complex, multistory fossil concentrations recording background and episodic processes. Hence, those fossil concentrations show high degrees of time-averaging and poor palcoecological resolution (except for the bivalves preserved in situ).

Quantitative estimates of time-averaging in terebratulid brachiopod shell accumulations from a modern tropical shelf

Quantitative estimates of time-averaging in marine shell accumulations available to date are limited primarily to aragonitic mollusk shells. We assessed time-averaging in Holocene assemblages of calcitic brachiopod shells by direct dating of individual specimens of the terebratulid brachiopod Bouchardia rosea. The data were collected from exceptional (brachiopod-rich) shell assemblages, occurring surficially on a tropical mixed carbonate-siliciclastic shelf (the Southeast Brazilian Bight, SW Atlantic), a setting that provides a good climatic and environmental analog for many Paleozoic brachiopod shell beds of North America and Europe. A total of 82 individual brachiopod shells, collected from four shallow (5-25 m) nearshore (<2.5 km from the shore) localities, were dated by using amino acid racemization (D-alloisoleucine/L-isoleucine value) calibrated with five AMS-radiocarbon dates (r(2) = 0.933). This is the first study to demonstrate that amino acid racemization methods can provide accurate and precise ages for individual shells of calcitic brachiopods.The dated shells vary in age from modern to 3000 years, with a standard deviation of 690 years. The age distribution is strongly right-skewed: the young shells dominate the dated specimens and older shells are increasingly less common. However, the four localities display significant differences in the range of time-averaging and the form of the age distribution. The dated shells vary notably in the quality of preservation, but there is no significant correlation between taphonomic condition and age, either for individual shells or at assemblage level.These results demonstrate that fossil brachiopods may show considerable time-averaging, but the scale and nature of that mixing may vary greatly among sites. Moreover, taphonomic condition is not a reliable indicator of pre-burial history of individual brachiopod shells or the scale of temporal mixing within the entire assemblage. The results obtained for brachiopods are strikingly similar to results previously documented for mollusks and suggest that differences in mineralogy and shell microstructure are unlikely to be the primary factors controlling the nature and scale of time-averaging. Environmental factors and local fluctuations in populations of shell-producing organisms are more likely to be the principal determinants of time-averaging in marine benthic shelly assemblages. The long-term survival of brachiopod shells is incongruent with the rapid shell destruction observed in taphonomic experiments. The results support the taphonomic model that shells remain protected below (but perhaps near) the surface through their early taphonomic history. They may be brought back up to the surface intermittently by bioturbation and physical reworking, but only for short periods of time. This model explains the striking similarities in time-averaging among different types of organisms and the lack of correlation between time-since-death and shell taphonomy.

Isotope geochemistry of the mafic dikes from the Vazante nonsulfide zinc deposit, Brazil

The Vazante Group, located in the northwestern part of Minas Gerais, hosts the most important zinc mine in Brazil, the Vazante Mine, which represents a major known example of a hypogene nonsulfide zinc deposit. The main zinc ore is represented by willemite and differs substantially from other deposits of the Vazante-Paracatu region, which are sulfide-dominated zinc-lead ore. The age of the Vazante Group and the hosted mineralization is disputable. Metamorphosed mafic dikes (metabasites) that cut the metasedimentary sequence and are affected by hydrothermal processes recently were found and may shed light on the geochronology of this important geological unit. Zircon crystals recovered from the metabasites are xenocrystic grains that yield U-Pb conventional ages ranging from 2.1 to 2.4 Ga, so the basement of the Vazante Group is Paleoproterozoic or has metasedinientary rocks whose source area was Paleoproterozoic. Pb isotopes determined for titanite separated from the metabasites have common, nonradiogenic Ph compositions, which prevents determination of their crystallization age. However, the Pb signatures observed for the titanite crystals are in agreement with those determined for galena from the carbonate-hosted Zn-Pb deposits hosted by the Vazante Group, including galena from minor sulfide ore bodies of the Vazante deposit. These similarities suggest that the metalliferous fluids that affected the metabasites may have been those responsible for galena formation, which could imply a similar lead source for both nonsulfide and sulfide zinc deposits in the Vazante-Paracatu district. This common source could be related to deep-seated, basin-derived, metalliferous fluids associated with a long-lived hydrothermal system related to diagenesis and deformation of the Vazante Group during the Neoproterozoic. (c) 2005 Elsevier Ltd. All rights reserved.

First record of petrified Permian pecopterids from the Parana Basin, Brazil (Corumbatai Formation, Passa Dois Group, northeastern State of São Paulo): Morphology, anatomy and paleoecological implications

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

Fidelity of molluscan assemblages from the touro passo formation (pleistocene-holocene), southern brazil: taphonomy as a tool for discovering natural baselines for freshwater communities

This study is the first assessment of mollusk fossil assemblages relative to the compositional fidelity of modern mollusk living and death assemblages. It also shows that the sedimentary record can provide information on the original, non-human-impacted, freshwater malacofauna biodiversity, based on Late Pleistocene shells. The fossil mollusk assemblage from the Touro Passo Formation (Pleistocene-Holocene) was compared to living and death assemblages of the Touro Passo River, southern Brazil, revealing little resemblance between fossil and live-dead species composition. Although the living and death assemblages agree closely in richness, species composition, and species relative abundances (both proportional and rank), the fossil assemblage differs significantly from both modern assemblages in most of these measures. The fossil assemblage is dominated by the native endemic corbiculid bivalve Cyanocyclas limosa and the gastropod Heleobia aff. bertoniana. These are absent in the living assemblages, and both living and death assemblages are dominated by the alien Asiatic corbiculid C. fluminea, which is absent in the fossil assemblage. The fossil assemblage also contains, overall, a higher proportional abundance of relatively thick-shelled species, suggesting a genuine bias against the thinner- and smaller-shelled species. Our results suggest that contemporary environmental changes, such as the introduction of some alien freshwater mollusk species, together with post-burial taphonomic processes, are the main factors leading to the poor fidelity of the fossil assemblage studied. Hence, the taxonomic composition of the Late Pleistocene mollusks from the Touro Passo Formation probably would show greater similarity to present-day assemblages wherever the mollusk biodiversity is not disturbed by human activities.

Mapeamento das formacoes superficiais da Regiao de Sao Pedro- Piracicaba (SP, Brasil).

As criteria in photointerpretation slope features, tonality, texture, structure, vegetation density and gullies were utilized. The origin of the surficial formations is related to the weathering, erosion and deposition processes and little diagenesis.-after English summary

Tafonomia de Pelecípodes da Formação Teresina (Permiano), Tiaraju, RS, Brasil

Taphonomic analysis of pelecypod concentration in the part of the Teresina Formation (Passa Dois Group), Tiaraju region, State of Rio Grande do Sul, indicates its origins as due to high energy events (storms). The fauna include shallow-burrowing suspensivorous species, associated with this byssate semi-infauna species. Several taphonomic characteristics indicate that the fossiliferous assemblage was subject to little selective processes during transportation. These are: predominance of disarticulated valves (although articulated valves are frequent) and perpendicular, oblique, concordant and nested arrangement of bioclasts in the sedimentary matrix. Absence of fragmentation, bioerosion and incrustation of the bioclasts, suggest fast burial of shells due to high sedimentation rate events. Diagenetic features, indicate that the fossils were later submitted to refossilization and mixing with other non-coeval bioclasts, resulting in some degree of time-averaging.

The temporal resolution of epibiont assemblages: Are they ecological snapshots or overexposures?

The effects of time averaging on the fossil record of soft-substrate marine faunas have been investigated in great detail, but the temporal resolution of epibiont assemblages has been inferred only from limited-duration deployment experiments. Individually dated shells provide insight into the temporal resolution of epibiont assemblages and the taphonomic history of their hosts over decades to centuries. Epibiont abundance and richness were evaluated for 86 dated valves of the rhynchonelliform brachiopod Bouchardia rosea collected from the inner shelf. Maximum abundance occurred on shells less than 400 yr old, and maximum diversity was attained within a century. Taphonomic evidence does not support models of live-host colonization, net accumulation, or erasure of epibionts over time. Encrustation appears to have occurred during a brief interval between host death and burial, with no evidence of significant recolonization of exhumed shells. Epibiont assemblages of individually dated shells preserve ecological snapshots, despite host-shell time averaging, and may record long-term ecological changes or anthropogenic environmental changes. Unless the ages of individual shells are directly estimated, however, pooling shells of different ages artificially reduces the temporal resolution of their encrusting assemblages to that of their hosts, an artifact of analytical time averaging. © 2006 by The University of Chicago. All rights reserved.

Diques clásticos na formação corumbataí (p) no nordeste da bacia do paraná, SP: Análise sistemática e significações estratigráficas, sedimentológicas e tectônicas

This paper aims to present the results of systematic survey on clastic dykes in the Corumbataí Formation (Permian), in the northeast region of the State of São Paulo. Besides this, the paper analyses genetic aspects of those features as well as their stratigraphic and sedimentologic implications in terms of geologic evolution of the northeastern Paraná Sedimentary Basin during Permian times. The field works had been developed in 3 main Corumbataí Formation outcrops (2 road cuts and a quarry) supposed to show the most important clastic dikes occurrences in the studied area. Basically, the sedimentary intrusions are formed by fine sand or silt size particles and had penetrated host rocks as near-vertical, centimeter thick, dykes (most common form) or as horizontal sheets, forming clastic sills (subsidiary form), both with variable geometric forms and dimensions. A lot of dyke walls show undulations suggesting pre-diagenetic clastic intrusions, probably near the ancient depositional surface. Almost all intrusions occur in the superior third portion of the Corumbataí Formation and some similar features seem to appear in the adjoining superposed Pirambóia Formation base. In this article the authors defend a seismic origin hypothesis for the clastic intrusions. It is important to mention that clastic intrusions tend to occur linked to expressive seismic events, with magnitude upper to 5. The analysis of isopach maps of the Permian and Mesozoic units of the Paraná Sedimentary Basin in the study area suggests a depositional system changing, from epicontinental sea conditions to shallow platform and, finally, to coastal deserts. Probably, this environmental change was driven by regional uplift accompanied by seismic events. It is possible that ancient seismicity triggered liquefaction processes and the resulting clastic intrusions. In this sense, those clastic features might be properly namedseismites.

Rochas ornamentais e de revestimento do sudoeste do estado do mato grosso

Geological, petrographical, chemicals and technological studies of rocks of the southwest region of Mato Grosso State, Brazil have the purpose of qualification and application of these rocks as dimension stones. The first objective is to enlarge the offering of new esthetic varieties that show a standardization of technologic patterns, adequate characterization and classification assuring the correct specification of the rocks in relation to the use as dimension stones. Ten rock types are recognized for dimension stones, including granites, diabases, gneisses and amphibolites grouped by its colors in red, grey and black types and showing economic potential of plowing. The results obtained in the technological essays show that the rock parameters are sited inside the standard limits established by technical rules and obey satisfactorily the limit values fixed for granites in internal and external covering uses.