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1.
Masato Kobiyama Aline de Almeida Mota Fernando Grison Joana Nery Giglio 《Natural Hazards》2011,59(2):1077-1086
The rainfall events that occurred in the Cubat?o do Norte River watershed, Santa Catarina State, Brazil, in 2008, were characterized
by both high intensities and amounts and triggered landslides in this watershed. The objective of the present study was to
analyze the influence of landslides on the turbidity and the total solid concentration (TS) in this river using turbidity,
TS, and river discharge data obtained from March 23, 2008, to June 11, 2010. The comparison between turbidity and discharge
patterns implies that the landslide process was not continuous and increased the turbidity intermittently and irregularly.
The sediment yield during the landslide occurrence was approximately five times higher than without the landslide, even though
the discharges were similar. The turbidity/discharge relationship during the landslide occurrence was markedly different from
that before and after the occurrence. The correlation coefficients between turbidity and TS showed that the landslide significantly
changed the sediment yield in this watershed. The result indicates that sediment yield estimations at the watershed level
should be treated more carefully when landslides occur. 相似文献
2.
Maria I. B. RAPOSO 《《地质学报》英文版》2016,90(Z1):163-163
正The Mesozoic magmatism in Southern Brazil is represented mainly by the basaltic flows of the Serra Geral Formation,the tholeiitic dikes swarms from the Ponta Grossa Arch,Florianópolis,and along the coast between 相似文献
3.
Vincenza Guarino Rogério Guitarrari Azzone Pietro Brotzu Celso de Barros Gomes Leone Melluso Lucio Morbidelli Excelso Ruberti Colombo Celso Gaeta Tassinari Mauro Brilli 《Mineralogy and Petrology》2012,104(1-2):43-61
The Ipanema alkaline-carbonatitic complex is part of the Meso-Cenozoic alkaline magmatism located within the southeastern part of the Brazilian Platform. Drill-core and field sampling have indicated the occurrence of glimmerites, with subordinate shonkinites (mela-syenites), clinopyroxene-bearing glimmerites, diorites and syenites. The glimmerites are cross-cut by lamprophyric dykes and calciocarbonatites. Fenitization has deeply affected the country rocks, originating dioritic and syenitic rocks. The Ipanema rocks show a distinct potassic affinity. The initial Sr-Nd- isotopic composition of the Ipanema rocks (87Sr/86Sr?=?0.70661–0.70754 and 143Nd/144Nd?=?0.51169–0.51181) is similar to that of tholeiitic and potassium-rich-alkaline rocks of the Eastern Paraguay. Stable isotope data for the Ipanema calciocarbonatite suggest interaction with fluids at temperatures typical of hydrothermal stages, as hypothesized for other carbonatite complexes from southeastern Brazil. The chemical differences between the lamprophyre, glimmerites, carbonatites, apatitites and magnetitites, and the absence of marked REE enrichment in the evolved lithologies, all indicate that fractional crystallization and accumulus of liquidus phases in a magma reservoir, likely coupled with liquid immiscibility processes, may have played an important role in the genesis of the Ipanema rocks. 相似文献
4.
Please refer to the attachment(s) for more details. 相似文献
5.
José Maria Filippini-Alba Carlos Roberto de Souza Filho 《Environmental Earth Sciences》2010,59(5):1139-1147
The Ribeira Valley region (State of Sao Paulo, Brazil) hosts the largest Brazilian Atlantic forest reserve. The region was
an important mineral district during the ‘60s, from where several tons of lead and other metals were exploited. Residual materials
produced by the mining are diffused in the environment until today. The area also encompasses a regional arsenium anomaly
associated with unexplored gold deposits. The population presently living in this region performs basic farming activities,
from which most of their food is yielded. These features coupled together imply in a complex relationship between natural
and anthropogenic factors that are likely to affect the life and health of the local communities. The aim of this paper is
to apply digital data integration techniques for environmental risk assessment in the Ribeira Valley using environmental geochemistry.
Geochemical, digital elevation and remote sensing data (Landsat Thematic Mapper) were merged and analyzed using a geographical
information system. The assumed model considered environmental mobilization through erosion and anomalous As–Pb areas. Data
were analyzed through Boolean and fuzzy logic techniques. Fuzzy logic proved superior in this case study as it allowed not
only the detection but also the distinction between low, moderate and high environmental risk areas. 相似文献
6.
《Chemie der Erde / Geochemistry》2019,79(4):125538
Roaldite – Fe4N – has been identified in the São Julião de Moreira iron meteorite using electron backscatter diffraction (EBSD) and simultaneously acquired energy-dispersive x-ray spectroscopy (EDS). Mean-periodic-number images derived from raw EBSD patterns confirm this phase by an even higher spatial resolution compared to EDS.Roaldite appears in the form of systematically and repetitively aligned plates. Despite the locally heavy plastic deformation, it is shown that the origin of the oriented precipitation of roaldite is linked to the orientation of the kamacite matrix. Roaldite can be considered to be precipitated from kamacite using an inverse Kurdjumov-Sachs (K-S) or Nishiyama-Wassermann (N-W) orientation relationship. A more accurate discrimination is impossible due to the accumulated shock deformation, which blurs the local reference orientation of kamacite. The habit plane of roaldite is found to be {112}R, which is most likely parallel to {120}K of kamacite. Some of the roaldite plates contain two orientation variants which repeatedly alternate. Their misorientation angle is about 12°. 相似文献
7.
Hiroyuki Kagi Dmitry A. Zedgenizov Hiroaki Ohfuji Hidemi Ishibashi 《Geochemistry International》2016,54(10):834-838
We report cloudy micro- and nano-inclusions in a superdeep diamond from São-Luiz, Brazil which contains inclusions of ferropericlase (Mg, Fe)O and former bridgmanite (Mg, Fe)SiO3 and ringwoodite (Mg, Fe)2SiO4. Field emission-SEM and TEM observations showed that the cloudy inclusions were composed of euhedral micro-inclusions with grain sizes ranging from tens nanometers to submicrometers. Infrared absorption spectra of the cloudy inclusions showed that water, carbonate, and silicates were not major components of these micro- and nano-inclusions and suggested that the main constituent of the inclusions was infrared-inactive. Some inclusions were suggested to contain material with lower atomic numbers than that of carbon. Mineral phase of nano- and micro-inclusions is unclear at present. Microbeam X-ray fluorescence analysis clarified that the micro-inclusions contained transition metals (Cr, Mn, Fe, Co, Ni, Cu, Zn) possibly as metallic or sulfide phases. The cloudy inclusions provide an important information on the growth environment of superdeep diamonds in the transition zone or the lower mantle. 相似文献
8.
《Applied Geochemistry》2004,19(4):575-591
The weathering rate of rocks and chemical dynamics of the Corumbataı́ River basin, São Paulo State, Brazil, were evaluated using major elements as natural tracers. This basin has serious environmental problems in terms of quality of surface and rainwater, which affect the determination of weathering rate. The Corumbataı́ River, downstream from Rio Claro City, receives several elements/compounds through anthropogenic activities, with only K, SO42− and alkalinity yielding positive flux values. The negative flux of some anions/cations can be attributed to atmospheric loading mainly related to anthropogenic inputs, providing K a value of 16.7 ton/km−2a−1 for the material removed by weathering in the Corumbataı́ River basin. This is equivalent to 26×106 kg of rock being removed each year by the Corumbataı́ River. The instantaneous flux was found to be a function of discharge, with the majority of dry residue (dissolved load) being transported during the summer (wet) months. The removed material in Corumbataı́ River basin derives mainly from two sub-basins (Cabeças River and Passa Cinco River), where the sandstones weather more easily than siltstones and claystones in the basin. 相似文献
9.
Luiz Bruner de Miranda Belmiro Mendes de Castro Björn Kjerfve 《Estuaries and Coasts》1998,21(2):204-214
Bertioga Channel is a partially mixed (type 2) tidal estuary on the coastal plain of São Paulo, Brazil. Hourly current and salinity measurements during neap and spring tides in July 1991 yielded information about the physical structure of the system. Peak along-channel velocities varied from 40 cm s?1 to 60 cm s?1 during flood tides and from 70 cm s?1 to 100 cm s?1 during ebb tides. Net vertical velocity profiles indicate that the net current reverses directions at a depth of 2.5–3.0 m in the halocline. Due to appreciable fortnightly tidal modulation, the estuary alternates from being highly stratified (type 2b) during neap tides, with advection and diffusion contributing equally to the net upstream salt flux, to being moderately stratified (type 2a) during spring tides, when 90% of the net upstream salt transport is the result of effective tidal diffusion. Decomposition of the salt flux indicates that the relative contribution to the upstream salt transport by gravitational circulation shear is greater than the oscillatory tidal flux by a factor of 2.6 during neap tides. The oscillatory tidal flux is generated by the correlation of the tidal components of the u-velocity and salinity and is responsible for approximately the same amount of upstream salt transport, during neap and spring tides. However, during spring tides, this oscillatory term is greater than the other salt flux terms by a factor of 1.4. The total salt transport, through a unit width of the section perpendicular to the flow, was within 2% of the sum of the seven major decomposed, advective and dispersive terms. On the assumption that the Bertioga Channel is laterally homogeneous, the results also indicate that the estuary is not in steady state with respect to salt flux. 相似文献
10.
Wilson TEIXEIRA Vicente A. V.. GIRARDI Maurizio Mazzucchelli Elson P. OLIVEIRA Paulo C. CORRêA DA COSTA 《《地质学报》英文版》2016,90(Z1):26-27
正Several generations of mafic dyke swarms(2.7 to 0.8Ga),highlighted by aeromagnetic data,petrography,geochemistry,isotope geology and mostly U-Pb baddeleyite ages,crosscut the Archean and 相似文献
11.
Robson Willians da Costa Silva Walter Malagutti Filho 《Environmental Earth Sciences》2012,66(5):1371-1383
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, São 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. 相似文献
12.
In this study, environmental and natural vulnerability maps developed for a Brazilian coastal region at São Sebastião City in São Paulo State helped to address a better understanding of the ecosystem fragility. Intense anthropogenic activities take place in the site that are mainly related to the petroleum industry and involve the operation of refineries and storage/transport of gas/oil by pipelines. A Geographical Information System (GIS) allowed the maps elaboration and analysis, where the region vulnerability was classified into five indexes: very low, low, medium, high and very high. The results depicted well the most vulnerable areas in the site, which should receive special care for their preservation. They include the coastal zones, the fluvial marine plain, the mangrove and the urban area of São Sebastião City. The results reported herein also show that the approach utilized may provide the decision makers with tools to develop an integrated coastal zone management for preserving the environmental resources in São Sebastião municipality. The methodology adopted is of easy implementation and adaptation to other areas, only taking into account the decision rules fitting diverse criteria imposed by the new reality. 相似文献
13.
Stephen K. Boss 《Mathematical Geology》2000,32(2):159-185
Traditional undergraduate education in earth sciences does not emphasize data acquisition, analysis, or assessment. However, arrival of the information age dictates that earth sciences graduates be imbued with fundamental skills to organize, evaluate and process large data sets. Fortunately, the proliferation of remotely sensed data and its availability via the Internet provides many opportunities for earth science educators to meet these needs. Exercises to introduce students to data analysis have been designed utilizing data from the Tropical Atmosphere–Ocean (TAO) Array and the 1997–1998 El Niño episode in the tropical Pacific Ocean. The TAO Array is a grid of 69 buoys moored across the equatorial Pacific Ocean (8°N to 8°S and 95°W to 143°E) recording environmental data relevant to El Niño—Southern Oscillation (ENSO) processes. Data from the TAO Array is available in near-real-time (http://www.pmel.noaa.gov/toga-tao/realtime.html) or as archived ASCII files (http://www.pmel.noaa.gov/toga-tao/data-delivery.html) providing daily (sometimes hourly) records of environmental parameters for each buoy in the grid. Student exercises in data analysis begin with downloading data from buoy locations, parsing the data into spreadsheets, and organizing data by environmental parameter into yearly and monthly data sets. Analyses of reconstructed data include calculations of long-term averages of environmental parameters, seasonal climatologies, monthly climatologies and calculation of long-term, seasonal, and monthly anomalies. Finally, monthly anomaly maps produced by students are loaded sequentially into GIF-animation software to create time-series images illustrating the progress and development of the 1997–1998 El Niño event. 相似文献
14.
Juan Reynerio Fagundo-Castillo Joel José Carrillo-Rivera Iñaki Antigüedad-Auzmendi Patricia González-Hernández Roberto Peláez-Díaz Rebeca Hernández-Díaz Dámaso Cáceres-Govea José Ramón Hernández-Santana Margaret Suárez-Muñoz Clara Melián-Rodríguez Mónica Rodríguez-Piña 《Environmental Geology》2008,55(2):247-267
Flows of different hierarchy, which travel through limestone, schist, sandstone and ultra-basic rocks, with ages from the
Paleocene to the Jurassic, at Sierra del Rosario, Pinar del Río, Cuba, were characterized. The waters were sampled from 1984
until 2004 and the data were statistically processed by means of chemical equilibrium and physico-chemical models, under a
flow system view of interpretation. Results demonstrate that the physico-chemical properties of the water are controlled by
water–rock interaction resulting from residence time since rainwater infiltrate and the path it follows to the discharge zone
and the type of aquifer material the different groundwater flows are in contact with. Geochemical indices allow the definition
of the different types of flow (local, intermediate, regional) to be characterized, permitting a further definition of the
different flow systems and rock type involved, as well as its use for water supply and medical use. The main geochemical processes
which control the chemical composition acquisitions mode are: congruent dissolution of calcite, dolomite, and halite; incongruent
dissolution of plagioclase and microcline minerals; pyrite oxidation, sulphate reduction, and silica dissolution at the surface
or silica precipitation at deep saturation and circulation zones. 相似文献
15.
This work presents a new fossil plant-bearing area located in the municipalities of Duque Bacelar and Coelho Neto, Maranhão State, Brazil, recovered from lower Permian (Cisuralian) strata of the Pedra de Fogo Formation, northeastern portion of the Parnaíba Basin. The area comprises more than five exposures with assemblages formed mostly of large gymnosperm woods, a number of them in life-position (reaching up to ∼2.30 m in height and 1.15 m in diameter) and, in lesser degree, of horizontal tree-fern stems (up to 5 m in length), some of them being referable to Psaronius sp. The fossils are recorded in sedimentary beds of continental origin that accumulated in shallow, nearshore areas of large lakes, which eventually were affected by rapid burial episodes generated by non-channelized, high energy fluvial systems. The new fossil assemblages are included within lacustrine rocks placed at the base of the Pedra de Fogo Formation, i.e., Sílex Basal Member, near the contact with the underlying Piauí Formation (Pennsylvanian). This observation contrasts with previous studies at the southwestern portion of the basin, where the stratigraphic position of plant fossils is referred to the upper Pedra de Fogo Formation (Trisidela Member) or even to the overlying Motuca Formation. The new sites currently suffer damage from human activities and require urgent actions in order to protect them. Based on the current laws, some measures of protection for these sites are discussed and proposed herein. 相似文献
16.
《Applied Geochemistry》2002,17(2):105-116
The concentrations and possible chemical associations of Al, Fe, Mn, Ca, Cu, Pb, Cd, Zn, Ni and Cr in sediments of the Tietê-Pinheiros river system in São Paulo state, Brazil, were studied using a 3-step sequential extraction protocol recommended by the Standards, Measurements and Testing Programme (SM&T, formerly BCR). A single extraction with 0.1 mol l−1 HCl was applied in parallel to anoxic and air-dried samples. The river system crosses the metropolitan area of São Paulo (MASP), which houses a population of nearly 17 million people, and receives a large load of industrial and domestic wastes. Samples were collected from reservoirs in the surroundings of MASP, named Billings, Pirapora and Rasgão, and from the Barra Bonita reservoir, that is located in the Tietê river, 270 km downstream from São Paulo city. The distribution of metals indicates the recent pollution characteristics for samples from the Billings, Pirapora and Rasgão reservoirs. In these sediments the metals are associated to a large degree with reactive forms such as sulphides and carbonates, or adsorbed to amorphous oxyhydroxides of Fe and Mn. In samples from Barra Bonita, heavy metals are mainly associated with the residual fraction, suggesting that their concentrations are controlled significantly by transport processes with fine particles as carriers from diffuse pollution sources. 相似文献
17.
Since Holocene time, above-mean precipitations recorded during the El Niño warm ENSO phase have been linked to the occurrence of severe debris flows in the arid Central Andes. The 2015–2016 El Niño, for its unusual strength, began driving huge and dangerous landslides in the Central Andes (32°) in the recent South Hemisphere summer. The resulting damages negatively impacted the regional economy. Despite this, causes of these dangerous events were ambiguously reported. For this reason, a multidisciplinary study was carried out in the Mendoza River valley. Firstly, a geomorphological analysis of affected basins was conducted, estimating morphometric parameters of recorded events such as velocity, stream flow, and volume. Atmospheric conditions during such events were analyzed, considering precipitations, snow cover, temperature range, and the elevation of the zero isotherm. Based on our findings, the role of El Niño on the slope instability in the Central Andes is more complex in the climate change scenario. Even though some events were effectively triggered by intense summer rainstorm following expectations, the most dangerous events were caused by the progressive uplifting of the zero isotherm in smaller basins where headwaters are occupied by debris rock glaciers. Our research findings give light to the dynamic coupled system ENSO–climate change–landslides (ECCL) at least in this particular case study of the Mendoza River valley. Landslide activity in this Andean region is driven by wetter conditions linked to the ENSO warm phase, but also to progressive warming since the twentieth century in the region. This fact emphasizes the future impact of the natural hazards on Andean mountain communities. 相似文献
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