Semi-arid Northeast Brazil Research Articles

Implicit Stochastic Optimization for deriving reservoir operating rules in semiarid Brazil

This paper deals with the application of Implicit Stochastic Optimization (ISO) to determine monthly operating rules for a reservoir system located in the semiarid Northeast of Brazil. ISO employs a deterministic optimization model to find optimal reservoir allocations under several possible inflow scenarios and later constructs the rules by analyzing the ensemble of these optimal releases. The operating policies provide the monthly reservoir release conditioned on the storage at the beginning of the month and the inflow predicted for the month. In addition to the classical regression analysis, this study establishes the rules by a two-dimensional interpolation strategy. After the rules are identified, they are applied to operate the system under new inflow realizations and show ability to produce policies similar to those obtained by deterministic optimization taking the same inflows as perfect forecasts.

Climate change and irrigation water requirement at Jaguaribe river basin, semi-arid northeast of Brazil

Climate change and irrigation water requirement at Jaguaribe river basin, semi-arid northeast of Brazil

Climate change and irrigation water requirement at Jaguaribe river basin, semi-arid northeast of Brazil

This article was submitted without an abstract, please refer to the full-text PDF file.

Illite neoformation in plagioclase during weathering: evidence from semi-arid Northeast Brazil.

Illite neoformation in plagioclase during weathering: evidence from semi-arid Northeast Brazil.

Magnetotelluric and aeromagnetic investigations for assessment of groundwater resources in Parnaiba basin in Piaui State of North-East Brazil

In an attempt to locate the presence of possible groundwater resource regions in the semi-arid North-East Brazil, an integrated survey including aeromagnetic and magnetotelluric (MT) studies have been undertaken in the Guaribas region and only MT survey in the Caracol region. In the Guaribas region the aeromagnetic data, its analytic signal and Euler solutions reveal several subsurface small-scale faults and intrusives that are conducive to be potential groundwater resource regions. A total of about 22 broad-band magnetotelluric (MT) soundings in the period range of 0.006–300 s along two profiles on the marginal arcs of the intra-cratonic sedimentary Parnaíba basin in North-East Brazil have been made across the regional geological strike, the Senador Pompeu Lineament (SPL). SPL trends N40°E and marks a basement high reflecting an irregularity in the original basin geometry. While one of the MT profiles traverses across the SPL, the other lies only in the aeromagnetically surveyed sedimentary region. Two-dimensional inversion of MT data of both profiles shows that the sedimentary basin is conductive (100–150 Ω m) and shows as a thin graben with an average thickness of about 2–3 km beneath both profiles. The basin is located to be at shallow depths (from surface to about 500 m). Based on the facts that the study region falls on sedimentary region having low-to-very low permeability and also in accordance with the subsurface lithology around the study region, the mapped sedimentary basin largely manifests the zone of potential sedimentary aquifer having moderate resistivity of 50–250 Ω m and is located at relatively shallow depths. The identified aquifer zone is believed to have links with the Parnaiba River flowing at a distance of about 300 km NW from the study region. We discuss interpretation of our results of MT and aeromagnetic data sets in the light of hydrological features of the study region.

The impact of upstream water abstractions on reservoir yield: the case of the Orós Reservoir in Brazil

Water abstraction for irrigation upstream of a reservoir and its impact on reservoir yield and reliability are studied. Water demand and availability are strongly related in semi-arid environments where the irrigation sector is responsible for a large part of consumptive water use. Variations in water abstractions for irrigation depend on irrigation requirements per hectare and the size of the irrigated area. The Orós Reservoir in semi-arid Northeast Brazil has been taken as a case study. The results show that water abstracttion for irrigation is of significant importance for reservoir yield and reliability. Yield—reliability simulations for the study area show that taking into account upstream water abstraction for a reservoir yield of 20.0 m3/s results in a water-scarcity probability of 10% on an annual basis (90% reliability). This is only 5% if up-stream abstraction for irrigation is ignored. This study shows that observed land-use changes in the study area do have a significant impact on reservoir yield reliability. The variability of upstream water abstraction was found to be of low importance for reservoir yield and reliability.

Organic Matter Turnover in Light Fraction and Whole Soil Under Silvopastoral Land Use in Semiarid Northeast Brazil

Trees in silvopastoral systems can accumulate carbon (C) and nutrients under their canopies. Most studies measure only net changes in organic matter and nutrients without evaluating turnover of soil organic matter . Here, the change in vegetation cover from caatinga , a semideciduous thorn forest (principally C 3 metabolism) to buffel grass ( Cenchrus ciliaris L.) pasture (C 4 metabolism) was used to quantify in situ input and turnover rates of organic carbon 14 yr after land-use changes. The accretion of C under new pasture and loss of original caatinga C was studied for whole soil (WS) and light fraction (LF). The effects of two tree species preserved during selective clearing and one species planted after complete clearing of caatinga were evaluated. All trees prevented organic matter mineralization that occurred in surrounding cleared pasture. The C mineralization under pasture was twice as high (66% loss) in LF as in WS (34% loss) over 14 yr. The C 4 –C was similar under and outside the remnant and planted tree canopies, i.e., the input of new C 4 –C did not compensate for the loss of old C 3 –C that occurred following caatinga clearing and pasture establishment. The organic matter in this tropical, semiarid region mineralized rapidly with C half lives between 9 and 16 yr for LF and between 11 and 28 yr for WS. The 13 C data indicate that elevated C contents under preserved (WS and LF) and planted (LF) trees, relative to the pasture outside the tree canopies, largely represent C 3 –C inherited from the caatinga. In this silvopastoral system, derived from land-use changes from dry forest, the islands of fertility and organic matter under the trees were not built up and represent preserved, rather than new, C inputs. Los árboles en sistemas silvopastoriles pueden acumular carbono (C) y nutrientes debajo de sus doseles. Muchos estudios miden solo cambios netos en la materia orgánica y los nutrientes asociados sin evaluar la transformación actual de la materia orgánica del suelo. En este estudio el cambio en la cobertura vegetativa de la Caatinga, un bosque espinoso semideciduos (principalmente metabolismo C 3 ), a una pastura (metabolismo C 4 ) de grama buffel ( Cenchrus ciliaris L.) fue usado para cuantificar in situ la tasa de entrada y la transformación de carbono orgánico catorce años después del cambio de uso de suelo. El incremento de C debajo de la nueva pastura y la pérdida de carbono original de la Caatinga fueron estudiados para el suelo entero (WS) y la fracción livianas (LF). Los efectos de dos especies de árboles conservados durante la poda selectiva de la Caatinga y unas especies plantadas después de completar la poda de la Caatinga fueron evaluados. Todos los árboles impidieron la mineralización de materia orgánica que ocurrió en los alrededores de la pastura podada. La mineralización de C debajo de la pastura fue dos veces tan alta (66% pérdida) en el LF que en el WS (34% pérdida) através de los 14 años. El C 4 –C fue similar debajo y fuera de los doseles de los árboles remanentes y plantados, i.e., la entrada de nuevo C 4 –C no compenso la perdida de viejo C 3 –C que había ocurrido luego de la poda de la Caatinga y el establecimiento de la pastura. La materia orgánica en esta región tropical semiárida se mineralizó muy rápidamente con medias vidas entre los 9 y 16 años para el LF, y entre 11 y 28 años para el WS. Los datos de 13 C indica que los contenidos de C elevados debajo de los árboles preservados (WS y LF) y los árboles plantados (LF) relativo a la pastura fuera de los doseles de los árboles representa ampliamente el C 3 –C heredado de la Caatinga. En este sistema silvopastoril derivado de un cambio de uso de suelo de un bosque seco, las islas de fertilidad y materia orgánica debajo de los árboles no fueron edificaciones nuevas y representan establecimientos preservados más que nuevas entradas de C.

Desempenho de lisímetro de pesagem hidráulica de baixo custo no semi-árido nordestino

Medidas diretas de evapotranspiração de referência são importantes na avaliação e na calibração de métodos indiretos. Avaliou-se o desempenho de lisímetro de pesagem hidráulica de baixo custo, visando à determinação direta da evapotranspiração de referência (ETo), em área de assentamento rural no Semi-Árido nordestino. O lisímetro é de concepção simplificada, com travesseiros hidráulicos confeccionados com mangueira flexível de butil e revestida em náilon, interligados a um sistema manométrico com mercúrio e água. O equilíbrio do lisímetro foi estável, sendo o maior erro médio posicional de 3,93%. As calibrações geraram coeficientes de correlação superiores a 0,9993 e resoluções de leituras entre 0,095 e 0,134 mm. As leituras lisimétricas foram comparadas com estimativas da ETo obtidas, utilizando-se dos métodos de Penman-Monteith, Blaney-Criddle-FAO, Jensen-Haise e do Tanque Classe A-FAO. Adicionalmente, avaliou-se o desempenho de um tanque evaporimétrico simplificado, construído a partir de material reciclado, o qual vem sendo utilizado no manejo da irrigação em áreas de agricultura familiar. Todos os métodos analisados apresentaram bom desempenho, com medidas bem correlacionadas aàs do lisímetro, para o período estudado.

Organização comunitária de um encrave de cerrado sensu stricto no bioma Caatinga, chapada do Araripe, Barbalha, Ceará

Este trabalho visou caracterizar a organização comunitária de uma área de cerrado s.s. no semi-árido do nordeste brasileiro, situada no topo da chapada do Araripe, município de Barbalha, Ceará. Foi realizado o levantamento fitossociológico através de 200 pontos-quadrante nos quais foram medidos a altura e o diâmetro no nível do solo (DNS) das plantas com no mínimo 3 cm de diâmetro. Foram calculados os parâmetros relativos: densidade, dominância e valor de cobertura (VC). Foi realizada uma análise comparativa dos parâmetros obtidos com outras áreas de cerrado no Brasil. A densidade encontrada foi de 2.224 ind. ha-1 e área basal 19,2 m² ha-1, sendo inferiores aos já obtidos em outros levantamentos. Foram amostradas 43 espécies e 28 famílias. As populações com maior densidade foram as de Miconia albicans, Vismia guianensis e Casearia grandiflora, que foram representadas por arbustos finos e baixos. Entre as populações de maior VC, Byrsonima sericea e Qualea parviflora são espécies consideradas amplamente representadas no bioma cerrado, independente do aumento da aridez, como é o caso da chapada do Araripe A diversidade de Shannon (H') foi de 2,88 nats. ind.¹ e a equabilidade (J') de 0,77, ambos inferiores aos de outros levantamentos em áreas de cerrado s.s. pertencentes à área core do Cerrado no planalto Central. A disparidade entre os critérios de inclusão dificulta uma análise comparativa mais acurada e é aqui discutida.

Population dynamics and extracellular enzymes activity of mesophilic and thermophilic bacteria isolated from semi-arid soil of Northeastern Brazil

The dynamics of mesophilic and thermophilic bacterial population was studied in the bulk soil and rhizosphere of the grass Aristida adscensionis L. in a caatinga of the semi-arid Brazilian Northeast. Mesophilic heterotrophic bacteria, sporeforming bacteria and actinomycetes were significantly more abundant than thermophiles, and their counts were 106 - 107 CFU g-1 dry soil, showing weak fluctuations over the one-year study period. Thermophiles were below 106 CFU g-1 dry soil and, in general, demonstrated stronger fluctuations over the studied period. Among them, thermophilic actinomycetes showed the greatest decline during the dry season. No significant differences in microbial number were observed between bulk and rhizosphere soil. Mesophilic bacteria were represented mainly by Gram positive, filamentous organisms (actinomycetes) and by Gram positive, endospore-forming, rod-shaped organisms. All isolates of thermophilic bacteria were Gram positive, endospore-forming rods. Most of mesophilic isolates produced amylases and proteases, and 38% of isolates produced all studied extracellular enzymes: amylases, proteases, cellulases and chitinases. Among thermophilic bacteria, all isolates showed proteolytic activity and 77% produced amylases, but no one produced cellulases or chitinases.

Serological markers of hepatitis A, B and C viruses in rural communities of the semiarid Brazilian Northeast

In the village of Cavunge, located in a dry tropical, semiarid rural region of the state of Bahia, Brazil, a sentinel study on viral hepatitis is underway. We report on the first part of the study. The objective of this study was to determine the prevalence of serological markers for hepatitis A, B and C in the village. Cross sectional study. Blood samples were tested for serological markers of hepatitis A (HAV), B (HBV) and C (HCV) through ELISA-III assay. In HBsAg and anti-HCV carriers, HCV-RNA and HBV-DNA were checked by PCR. The prevalence of anti-HAV IgG was 83.3% (1,210/1,452), being higher among residents from the village (87.4%) than in residents from the rural area (79.5%); it also higher among individuals older than 10 years of age. The prevalence of HBsAg was 2.6% (38/1,476), 9.3% anti-HBc (137/1,476) and 10.5% (155/1,476) anti-HBs of. In more than half (58.1%; 90/155) of anti-HBs carriers, this was the only serological marker found. In 3.7% of the population, (55/1,476), anti-HBc was the only serological marker found. All HBV carriers were infected by genotype A. Only 0.4% (6/1,536) presented anti-HCV antibodies and only one of them was viremic, being infected with genotype 1. The prevalence of patients with antibodies against hepatitis A virus in the village of Cavunge was high, but the prevalence of B virus was moderate, with only genotype A among HBV carriers. The prevalence of C virus was very low, contrasting with the situation in large Brazilian urban centers.

Integrated modelling of climate, water, soil, agricultural and socio-economic processes: A general introduction of the methodology and some exemplary results from the semi-arid north-east of Brazil

Many semi-arid regions are characterised by water scarcity and vulnerability of natural resources, pronounced climatic variability and social stress. Integrated studies including climatology, hydrology, and socio-economic studies are required both for analysing the dynamic natural conditions and to assess possible strategies to make semi-arid regions less vulnerable to the present and changing climate. The model introduced here dynamically describes the relationships between climate forcing, water availability, agriculture and selected societal processes. The model has been tailored to simulate the rather complex situation in the semi-arid north-eastern Brazil in a quantitative manner including the sensitivity to external forcing, such as climate change. The selected results presented show the general functioning of the integrated model, with a primary focus on climate change impacts. It becomes evident that due to large differences in regional climate scenarios, it is still impossible to give quantitative values for the most probable development, e.g., to assign probabilities to the simulated results. However, it becomes clear that water is a very crucial factor, and that an efficient and ecologically sound water management is a key question for the further development of that semi-arid region. The simulation results show that, independent of the differences in climate change scenarios, rain-fed farming is more vulnerable to drought impacts compared to irrigated farming. However, the capacity of irrigation and other water infrastructure systems to enhance resilience in respect to climatic fluctuations is significantly constrained given a significant negative precipitation trend.

A SALINIDADE DAS ÁGUAS SUPERFICIAIS E SUBTERRÂNEAS NA BACIA DA GAMELEIRA, MUNICÍPIO DE AIUABA/CE

Surface waters from three dams and groundwaters from three wells dug in alluvium, located in the Gameleira watershed in an area of restricted human action in the semi-arid Northeast of Brazil, were studied through chemical and physicochemical measurements for the identication of the origin of dissolved minerals and of the processes of salination. Results show that salts result from dissolution during water/rock interaction and from atmospheric precipitation. In both types of storage, evaporation is identified as an agent of salt enrichment, principally in surface waters. Waters sampled were chemically adequate for human consumption; however,anthropic action influences nitrate concentration.

In vitro Activities of Caspofungin, Amphotericin B and Azoles Against Coccidioides posadasii Strains from Northeast, Brazil

Coccidioidomycosis is a systemic infection caused by the soil-dwelling dimorphic fungi Coccidioides spp. The disease is endemic in semiarid Northeast Brazil, where it is caused by C. posadasii. The aim of this study was to perform antifungal susceptibility tests of clinical and environmental strains of C. posadasii from Northeast Brazil. The in vitro activities of caspofungin, amphotericin B and azoles against clinical and environment isolates of C. posadasii were determined in accordance with the NCLLS M-38P macrodilution method. The antifungal susceptibility analysis showed that all the strains of C. posadasii (n = 10) were sensitive to caspofungin (16 microg/ml < or = MIC < or = 32 microg/ml), amphotericin B (0.0625 mug/ml < or = MIC < or = 0.125 microg/ml), ketoconazole (0.039 microg/ml < or = MIC < or = 0.156 microg/ml), itraconazole (0.125 microg/ml < or = MIC < or = 0.5 microg/ml), fluconazole (3.125 microg/ml < or = MIC < or = 6.25 microg/ml), and voriconazole (0.125 microg/ml). This study is the first description of in vitro antifungal susceptibility pattern of Brazilian strains of C. posadasii.

Regional integrated modelling of climate change impacts on natural resources and resource usage in semi-arid Northeast Brazil

Semi-arid regions are characterised by a high vulnerability of natural resources to climate change, pronounced climatic variability and often by water scarcity and related social stress. The analysis of the dynamics of natural conditions and the assessment of possible strategies to cope with drought-related problems require an integration of diverse knowledge including climatology, hydrology, and socio-economics. The integrated model introduced here dynamically describes the relationships between climate forcing, water availability, agriculture and selected societal processes. The model has been designed to simulate the complex human-environment system in semi-arid Northeast Brazil quantitatively and is applied to study the sensitivity of regional natural resources and socio-economy to climate change. The validity of the model is considered. Climate change is concluded to have an enormous potential impact on the region. River flow, water storage and irrigated production are specifically affected, assuming a continuous regional development and unfavourable but plausible changes in climate. Under plausible favourable changes in climate, these variables remain stressed. The impact of the integrated model and its applications on present policy making and possible future roles are briefly discussed.

Simulação e avaliação do desempenho hidrológico da drenagem horizontal de percolado em aterro sanitário

A determinação da quantidade de percolado gerado em aterros sanitários continua sendo uma tarefa difícil, principalmente no semi-árido nordestino onde predominam caracteríticas meteorológicas e geológicas bem peculiares. O programa HELP (avaliação do comportamento hidrológico em aterros sanitários), desenvolvido por Schroder et al (1984), foi utilizado na simulação de várias configurações de drenagem de fundo. Aplicou-se ao modelo, dados meteorológicos e de solos da região onde está o aterro sanitário de Caucaia (ASMOC), a qual é representativa do semi-árido nordestino. Três características da drenagem de fundo foram variadas (configuração da drenagem, inclinação de fundo e adição de uma camada drenante com alta permeabilidade) com o objetivo de avaliar a altura da coluna de percolado, a quantidade de percolado infiltrado no solo e o volume coletado para tratamento. Nas trincheiras sem camada drenante, o aumento da inclinação de fundo e a alteração da configuração dos drenos tiveram pouca influência sobre as variáveis estudadas. A adição da camada drenante proporcionou uma redução significativa da altura da coluna e na infiltração de percolado no solo, mostrando que é um componente fundamental para o bom funcionamento do sistema de drenagem horizontal em aterros sanitários.

Simple water balance modelling of surface reservoir systems in a large data-scarce semiarid region / Modélisation simple du bilan hydrologique de systèmes de réservoirs de surface dans une grande région semi-aride pauvre en données

Water resources in dryland areas are often provided by numerous surface reservoirs. As a basis for securing future water supply, the dynamics of reservoir systems need to be simulated for large river basins, accounting for environmental change and an increasing water demand. For the State of Ceará in semiarid Northeast Brazil, with several thousands of reservoirs, a simple deterministic water balance model is presented. Within a cascade-type approach, the reservoirs are grouped into six classes according to storage capacity, rules for flow routing between reservoirs of different size are defined, and water withdrawal and return flow due to human water use is accounted for. While large uncertainties in model applications exist, particularly in terms of reservoir operation rules, model validation against observed reservoir storage volumes shows that the approach is a reasonable simplification to assess surface water availability in large river basins. The results demonstrate the large impact of reservoir storage on downstream flow and stress the need for a coupled simulation of runoff generation, network redistribution and water use.

Residual N and P fertilizer effect and fertilizer recovery on intercropped and sole-cropped corn and bean in semiarid northeast Brazil

The effects of a single 15N and P fertilizer application (16 and 12 kg ha–1) on intercropped and sole-cropped corn and beans was followed over three consecutive years. Grain (0.1–0.9 ton ha–1 yr–1) and straw productions (0.2–2.5 ton ha–1 yr–1) were limited by rainfall and showed small responses to fertilizer. In the first year, plant N uptake was more than twice the fertilizer amounts, while P uptake was less than half the fertilizer amounts. Plant N derived from fertilizer was low (9–19%). Sole corn took up more (34%) than beans (16%) and the combined intercrop (26%) and also had higher recovery of fertilizer in the soil than single beans (50% against 28%). The distribution of fertilizer N and P in the soil showed a similar pattern in all treatments, with a high concentration around the application spot and decreasing concentrations at greater distances and above and below this point. Total P increases in a soil volume 10 cm around the application spot corresponded to 60% of the amount applied. Fertilizer contributions to the second crop were < 3% of total plant N and represented <6% of the applied amount. Therefore, the residual fertilizer effect on production was attributable to P. The patterns of fertilizer N and P distribution in the soil remained similar but N recoveries decreased 14–18%. Despite low rainfall, low productivities and reasonable proportions of fertilizer N remaining in the soil, the residual effects of the applied fertilizer N were too low to justify a fertilizer recommendation based on economic returns on the investment.

PROSPECÇÃO DE ROCHAS ORNAMENTAIS AUXILIADA POR SISTEMA DE INFORMAÇÃO GEO-REFERENCIADA

Dimension Stones are an increasingly valuable commodity in Brazil, generating export revenues estimated to reach US$ 355 million in 2002. The proposed federal government target is to increase this amount to over US$ 600 million within four years. To this end, better exploration techniques will have to be applied in order to renew and replenish stocks. The use of GIS-based exploration techniques can improve target vectoring as well as speed up the discovery process. A three-phase approach was considered, consisting in digital processing (image generation, geometric corrections, mosaicing, filtering), databank generation (scanning, database compilation, thematic map generation) and GIS-based modeling and potential evaluation, achieved through the implementation of the economic-geological attractiveness index (IAEG in the Portuguese acronym), which considers field, laboratory and market characterization of dimension stones. Landsat and aerogammaspectrometry are used to aid geological mapping, with an emphasis on rock discrimination, whereas radar imagery was used mainly to characterize structural trends, rock unit contacts and ductile to brittle lineaments. The most useful combinations of Landsat data were R4-G3-B1, R7-G4-B1, R5-G4-B3 and (R) 5-7 (G) 4-3 (B) 3-1. For gammaspectrometry data, the used algorithms included total gamma count, Thorium-equivalent, Uranium-equivalent, Thorium/Uranium ratio, K-Th-U ternary maps, and the ternary composition of K-K/U-K/Th. Data integration allowed the extrapolation of the IAEG towards the western portion of the area and the comparison of analog and digital implementation of the methodology, which highlights the advantages of the digital media. A good correlation was obtained between the generalization of known occurrences and deposits implemented with the IAEG and the areas selected by GIS integration and modeling of the data. Three priority levels for follow-up are established and five areas have been selected. Two areas are located between the localities of Ingá and Caiçara and Cachoeira and Maravilha are chosen as first priorities, one broad area between Bom Nome and Rio da Barra as a second priority, and two third rate areas are selected near the locality of Queimada Nova. All five priorities are previously unworked and lie in the Custódia region, thus opening new exploration grounds for dimension stones in the semi-arid Northeast Brazil. The area is particularly appropriate for such industry (good outcrops, roads and port infrastructure, few environmentally sensitive sites) and dearly needs job generation to increase living standards and curb rural exodus.

PROSPECÇÃO DE ROCHAS ORNAMENTAIS AUXILIADA POR SISTEMA DE INFORMAÇÃO GEO-REFERENCIADA

Dimension Stones are an increasingly valuable commodity in Brazil, generating export revenues estimated to reach US$ 355 million in 2002. The proposed federal government target is to increase this amount to over US$ 600 million within four years. To this end, better exploration techniques will have to be applied in order to renew and replenish stocks. The use of GIS-based exploration techniques can improve target vectoring as well as speed up the discovery process. A three-phase approach was considered, consisting in digital processing (image generation, geometric corrections, mosaicing, filtering), databank generation (scanning, database compilation, thematic map generation) and GIS-based modeling and potential evaluation, achieved through the implementation of the economic-geological attractiveness index (IAEG in the Portuguese acronym), which considers field, laboratory and market characterization of dimension stones. Landsat and aerogammaspectrometry are used to aid geological mapping, with an emphasis on rock discrimination, whereas radar imagery was used mainly to characterize structural trends, rock unit contacts and ductile to brittle lineaments. The most useful combinations of Landsat data were R4-G3-B1, R7-G4-B1, R5-G4-B3 and (R) 5-7 (G) 4-3 (B) 3-1. For gammaspectrometry data, the used algorithms included total gamma count, Thorium-equivalent, Uranium-equivalent, Thorium/Uranium ratio, K-Th-U ternary maps, and the ternary composition of K-K/U-K/Th. Data integration allowed the extrapolation of the IAEG towards the western portion of the area and the comparison of analog and digital implementation of the methodology, which highlights the advantages of the digital media. A good correlation was obtained between the generalization of known occurrences and deposits implemented with the IAEG and the areas selected by GIS integration and modeling of the data. Three priority levels for follow-up are established and five areas have been selected. Two areas are located between the localities of Inga and Caicara and Cachoeira and Maravilha are chosen as first priorities, one broad area between Bom Nome and Rio da Barra as a second priority, and two third rate areas are selected near the locality of Queimada Nova. All five priorities are previously unworked and lie in the Custodia region, thus opening new exploration grounds for dimension stones in the semi-arid Northeast Brazil. The area is particularly appropriate for such industry (good outcrops, roads and port infrastructure, few environmentally sensitive sites) and dearly needs job generation to increase living standards and curb rural exodus.