Deposition and tectonic setting of the Palaeoproterozoic Castelo dos Sonhos metasedimentary formation,Tapajós Gold Province,Amazonian Craton,Brazil: age and isotopic constraints

The Castelo dos Sonhos Formation (CSF) represents a relic of a sedimentary basin located in the southeastern Tapajós Gold Province (TGP), at its boundary with the Iriri–Xingu Domain (IX), south of the Amazonian Craton. The formation comprises mature, coarse-grained metasandstones (quartz-arenites) intercalated with auriferous metaconglomerates with clasts of quartz and subordinately of banded iron formation, quartzite, schist, and felsic metavolcanic rocks. Lithology, planar, channelled, and large-scale cross-bedding suggest deposition in continental setting by the braided fluvial system associated with alluvial fans and subordinate aeolian dunes. The rocks underwent very low metamorphism and gently synformal folding, and were intruded by andesites and granitoids (2011–1918 Ma). U–Pb LA-ICP-MS zircon data indicate maximum depositional ages of 2050 Ma (metaconglomerate) and 2074, 2088, and 2104 Ma (metasandstones). Hence, deposition occurred at 2050–2011 Ma, slightly preceding or being coeval with the onset of the orogenic phase in TGP (2030–1956 Ma). The quartz-arenite composition, zircon U–Pb data, and negative εHf (?1.3 to ?13.0) and εNd (?2.9 to ?5.3) values indicate: (1) quartzose provenance, (2) prolonged transport and recycling of sedimentary sources, (3) multiple age peaks (2050–3700 Ma), with predominant sources of 2100 and 2750 Ma, and (4) long crustal residence time for the source rocks. Source areas were Rhyacian–Siderian orogenic belts to Mesoarchaean terranes of the Amazonian Craton located to the east, southeast, and northeast of TGP, along with Palaeoarchaean and Eoarchaean detrital zircons recycled from older sedimentary rocks. We interpret CSF as part of a larger foreland system related to the evolution of Rhyacian orogens, currently represented by the Bacajá and Santana do Araguaia domains. The present location of CSF in the easternmost TGP, close to its boundary with IX, is due to rifting (1.89–1.80 Ga) that produced the Uatumã Silicic Large Igneous Province (Uatumã SLIP), and the juxtaposition of the crustal domains is supported by gravity data.     

Forest Fire Alert System: a Geo Web GIS prioritization model considering land susceptibility and hotspots – a case study in the Carajás National Forest,Brazilian Amazon

To increase the monitoring potential of forest fires, an alert classification methodology using satellite-mapped hotspots has been established to help forest managers in the prioritization of which hotspot to be verified in the field, thus potentially improving the distribution of fire-fighting resources. A computer application was developed based on web-distributed geographical information technology whose main function is to interact automatically generated satellite hotspots and risk areas indicated in fire-susceptibility maps and classify them into five alert levels. The location of the hotspots is available continuously every 4 h, and a susceptibility map is produced daily through map algebra algorithm, which uses static (topography, vegetation and land use) and dynamic (weather) variables. Every process runs through automated geoprocessing routines. The methodology was tested during the dry period of 2007 in the Carajás National Forest, in the Brazilian Amazon, within an area of 400,000 ha. It is a critical area constantly threatened by fires caused by invasions and deforestation owing to intense agribusiness advances and mining activities in its surroundings. This situation results in observations of many hotspots inside the study area for the same day and almost the same time period, in places of extreme opposites, demanding complex rapid analysis and hindering the decision of the displacement of fire-fighting teams. Further, a major mining company operates within the National Forest area, maintaining actions of protection as part of its environmental mining license. Results are presented under three aspects: (i) the credibility of the daily susceptibility map (algorithm), which showed strong correlation between areas of greatest risks and the confirmed forest fires; (ii) the reliability of hotspots (alert levels), confirming 71% of fires; (iii) accuracy in the decision of which hotspot to be checked, which revealed the same number of verifications at different alert levels, 82% confirmed alert 5 hotspots (maximum) and only 50% from alert 1 (minimum), resulting in faster fire-fighting actions, minimizing burned areas and, in some cases, allowing fire control before its spreading. Therefore, the methodology demonstrated that GIS routines are able to determine the relationship between a reality-based, interpreted susceptibility map of the area and satellite-generated hotspots, highlighting the ones of highest hazard level through the alert classification, becoming an important tool to help decisions from the fire-control center, especially for high-risk regions. The methodology may be extrapolated to other forested areas.     

A GIS-based glacier inventory for the Antarctic Peninsula and the South Shetland Islands —A first case study on King George Island

The aim of the international project “Global Land Ice Measurements from Space (GLIMS)” headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery. This data set will form a first digital baseline study for future glacier monitoring. The presented GIS-based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula. In the database of the glacier inventory topographic information, specific glaciological parameters as well as metadata will be included. The topographic data consists of drainage basin limits, basin areas, altitudinal ranges, perimeters and mean lengths. Glaciological data sets should comprise information on glacier retreat in different periods, glacier velocities, ice thickness and bedrock topography as well as derived parameters. Modelled and measured mass balance parameters could be included as additional data layers. In particular, these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS). Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications, but also other environmental studies on the island will benefit from this standardised remote sensing data sets. Therefore, a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms. Finally, better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950's onward.     

“Global warming” versus “climate change”: A replication on the association between political self-identification,question wording,and environmental beliefs

Climate change is one of the greatest threats to humanity and requires immediate action. Schuldt, Konrath, and Schwarz (2011) suggested that beliefs in environmental phenomena can be influenced by the terminology used to describe it: changing question wording from global warming to climate change resulted in a 6.3 percentage point increase in belief in environmental phenomena. This association was moderated by political self-identification, with Republicans being 16.2 percentage points more likely to believe in climate change than in global warming, with Democrats showing no difference. The potential for connotative meanings to shift over time and the sociopolitical changes since the original study, potential policy and environmental campaign implications, and an expansion of these findings to other countries, motivated an attempt to replicate this important finding. This pre-registered study repeated the original procedures in the United States of America and two other countries (United Kingdom and Australia; total N = 5,717). Although question wording no longer had a significant effect on beliefs in climate change/global warming, the association of political self-identification with beliefs in environmental phenomena replicated in all three countries, with Conservatives consistently believing less in climate change/global warming than Liberals. The potential impacts of temporal and methodological differences on the discrepancies between this study's and the original's findings are discussed.     

Drinking water production from surface water sources in the tropics: Brasília DF,Brazil

Drinking water production at three waterworks was evaluated with respect to variable weather conditions in the Brasília Distrito Federal. Results of the investigation revealed that seasonal variations in rainfall play an important role in influencing the quality of the surface water sources used for drinking water production in the district. In most surface sources, particles and apparent colour are likely to originate from erosion during rain events. This represents the primary challenge facing waterworks, notably when the raw water qualities of the sources to be treated at one facility differ by one order of magnitude, as well significantly varying from one season to the next. Treatment efficiencies in terms of turbidity, apparent colour and dissolved organic carbon (DOC) removal were evaluated. Drinking water quality was found to be significantly influenced by raw water quality at all considered treatment plants. With regard to DOC removal, treatment was most efficient in waterworks which treated raw water with high percentages of biopolymers and humics. Most dissolved organics were removed by coagulation. Finally, conclusions are drawn on how to better cope with challenges facing drinking water production in a tropical climate. The first of these recommendations is the introduction of online turbidity and dissolved organic matter monitoring in order to optimise the coagulation process for the removal of these two parameters. A combination of different coagulants could also be considered for this process. Additional more sophisticated improvements to process stability, such as determination of floc characteristics, introduction of artificial neural networks or the eventual upgrade of the treatment train using membrane filtration, are also suggested.     

A computational study of nonresonant cross-field diffusion of energetic particles due to their interaction with interplanetary magnetic decreases

We present a new method of calculating cross-field diffusion of charged particles due to their interactions with interplanetary magnetic decreases (MDs) in high heliospheric latitudes. We use a geometric model that evaluates perpendicular diffusion to the ambient magnetic field as a function of particle's gyroradius, MD radius, ratio between fields outside and inside the MD, and a random impact parameter. We use Ulysses magnetic field data of 1994 to identify the MDs and get the empirical size and magnetic field decrease distribution functions. We let protons with energies ranging from 100 keV to 2 MeV interact with MDs. The MD characteristics are taken from the observational distribution functions using the Monte Carlo method. Calculations show that the increase in diffusion tends to saturate when particles' gyroradius becomes as large as MD radii, and that particles' gyroradius increases faster than diffusion distance as the energy of the particles is increased.     

“Global warming” versus “climate change”: A replication on the association between political self-identification,question wording,and environmental beliefs

Climate change is one of the greatest threats to humanity and requires immediate action. Schuldt, Konrath, and Schwarz (2011) suggested that beliefs in environmental phenomena can be influenced by the terminology used to describe it: changing question wording from global warming to climate change resulted in a 6.3 percentage point increase in belief in environmental phenomena. This association was moderated by political self-identification, with Republicans being 16.2 percentage points more likely to believe in climate change than in global warming, with Democrats showing no difference. The potential for connotative meanings to shift over time and the sociopolitical changes since the original study, potential policy and environmental campaign implications, and an expansion of these findings to other countries, motivated an attempt to replicate this important finding. This pre-registered study repeated the original procedures in the United States of America and two other countries (United Kingdom and Australia; total N = 5,717). Although question wording no longer had a significant effect on beliefs in climate change/global warming, the association of political self-identification with beliefs in environmental phenomena replicated in all three countries, with Conservatives consistently believing less in climate change/global warming than Liberals. The potential impacts of temporal and methodological differences on the discrepancies between this study's and the original's findings are discussed.     

Effect of the addition of granitic powder to an acidic soil from Galicia (NW Spain) in comparison with lime

The impact of diffuse pollution, agricultural land use and climate change on the long-term response of subsurface–surface water quality is not well understood, but is a prerequisite for evaluation of water management options. The goal of this study is to model geochemical evolution of water chemistry from the infiltration through soil into the unsaturated zone, transport through bedrocks and granular aquifers to a river in order to identify zones of steep concentration gradients and high dynamics under transient flow conditions. A numerical model was constructed comprising a 2-D 1,500 m × 150 m vertical cross-section of typical sedimentary rock formations, a glacio-fluvial quaternary gravel aquifer in the valley and soil layers. The model coupled saturated/un-saturated flow and reactive transport under steady state and transient conditions. Geochemical interactions, include intra-aqueous kinetic reactions of oxygen with dissolved organic matter, as well as kinetics of carbonate dissolution/precipitation. This model section was chosen to provide insight in to the principal processes and time scales affecting water chemistry along different flow paths. The numerical simulator MIN3P was used, a finite volume program for variably saturated subsurface flow and multi-component reactive transport. The results show that subsurface water residence times range from approximately 2 to 2,000 years. Different zones are to be expected with respect to the development of mineral equilibria; namely, purely atmospherically influenced, as well as open and closed system carbonate dissolution. Short-term responses to daily averaged changes in precipitation, however, are only visible to some extent in the shallower and near-river parts of flow system and solute loads. This can most likely be explained by directional changes in flow paths, indicating that equilibrium geochemical condition predominate at the hillslope scale, i.e. water quality depends on transport pathways rather than on kinetic effects. The extent of reducing conditions is controlled by the presence of organic-rich layers (i.e. peat deposits), the dissolution kinetics of aquifer organic matter and the subsequent mixing with oxygenated water by hydrodynamic dispersion.     

Persistent organic pollutants and histological lesions in Mayan catfish Ariopsis assimilis from the Bay of Chetumal, Mexico

Livers of catfish (Ariopsis assimilis) from the Bay of Chetumal were analyzed for organochlorine compounds and hydrocarbons as part of a study to diagnose the environmental health of the Bay after a catfish mass mortality that occurred in 1996. The presence of histological lesions in several organs of the fish as result of chemical exposure was also evaluated. The concentrations of organic pollutants found in the Bay may be considered high if compared to the levels reported for sites affected by chemical pollution. High prevalences of cellular alteration histopathologies were found in liver, including hepatic tumors. The presence of some lesions may be related statistically to environmental pollution in the Bay, specially with chlorinated compounds.