Roberto Alexandre Vitória de Moraes

• Doctor of Philosophy
• Professor at University of Brasília

Brownfield areas are important targets of exploration; however, the extensive drilling present in these areas has not fully exploited their prospective potential. The appropriate use of drill hole cores in these areas can play an important role in deep exploration. We present a case study of iron oxide-copper-gold (IOCG) Furnas Southeast deposit, l...

The Argyle mine in Australia is well known for the number of pink diamonds produced, but production is expected to shut down in a few years. The authors present a review of the history of pink and red diamonds around the world and find that India and Brazil have produced more than half the pink diamonds of greater than 12 carats. Additionally, Braz...

The authors, in a paper in this journal in 2009, note a puzzle, that in spite of extensive exploration for diamonds by major producers in the Alto Paranaiba region of West Minas Gerais State, Brazil, no primary source, such as kimberlites, for the many diamonds produced since their discovery over 250 years has been found. To answer this puzzle we p...

Strong hydrothermal alteration modifies rock physical properties in iron oxide-copper-gold deposits (IOCGs) and may result in characteristic signatures detectable in geophysical surveys. Magnetic data are commonly used in characterizing orebodies, and 3D inversions are often used to assist in interpretations. In areas with strong remanence and self...

Archean nuclei are the result of complex tectonic processes that developed during the long evolutionary history of the Earth. These units are marked by tectonic signatures that resulted from multiple deformational events, crustal reworking and tectonic reactivation at different crustal levels. The understanding of their tectonic framework requires...

This paper is in Portuguese. Studies based on magnetic airborne geophysical data for determining the boundaries between mobile belts and tracks cratonic blocks, usually marked by great physical discontinuities represented by faults or shear zones. In the case of the boundaries are masked by recent coverage, the interpretation could be done by geoph...

Este trabalho apresenta o mapeamento do manto de intemperismo pelo comportamento da resitividade elétrica do Distrito Federal. O levantamento foi realizado entre 2004 e 2005, constituído de 260 sondagens elétricas verticais, que alcançam até 48 m de profundidade aparente, e de 10 estações de monitoramento mensal da resistividade elétrica para avali...

This paper is in Portuguese. This paper presents the results of an extensive processing, interpretation and geological integration of airborne gamma-ray spectrometric data. It comprised data from 30.360 linear kilometers of profiles, spaced 2000 m apart, covering an area of 54.000 km² in northwest Mato Grosso State (Rio do Sangue Project, DNPM/DGM/...

The aim of this paper is to carry out a comparison between two types of 2D electromagnetic modeled sections normally used on AEM data quantitative interpretation especially on those obtained from ATDEM measurements (ATDEM). One is obtained from fast modeling of the secondary magnetic flux decay and is the most common quantitative interpretation too...

The objective of subsurface imaging is to transform responses measured by ATDEM methods in an image of the electrical conductivity versus depth (CDI) and with this, to get information on target geometry and conductivity (geoelectrical model). This work presents a methodology to get CDIs over the measurement profile (2-D) used subsequently to visual...

The aim of this paper is to carry out a comparison between two types of 2D electromagnetic modeled sections normally used on AEM data quantitative Interpretation especially on those obtained from ATDEM measurements (ATDEM). One Is obtained from fast modeling of the secondary magnetic flux decay and Is the most common quantitative interpretation too...

The objective of subsurface imaging is to transform responses measured by ATDEM methods in an image of the electrical conductivity versus depth (CDI) and with this, to get information on target geometry and conductivity (geoelectrical model). This work presents a methodology to get CDIs over the measurement profile (2-D) used subsequently to visual...

This paper is in Portuguese. Airborne magnetic data are used as a tool in tectonic analysis of the Pre-Cambrian terrains with complex stratigraphic and structural relationships. This paper draw on the magnetic interpretation techniques for the identification of main tectonic structures, crustal blocks and tectonic boundaries present in the Rio Gran...

This paper is in Portuguese. The aim of this paper is to carry out a comparison between two types of 2D electromagnetic modeled sections. They are normally used on AEM (Airborne EletroMagnetic) quantitative interpretation, especially on those obtained from ATDEM measurements (ATDEM). One is derived from fast modeling of the asymptotic secondary mag...

This paper is in Portuguese. The objective of subsurface imaging is to transform responses measured by ATDEM methods in an image of the electrical conductivity versus depth (CDI) and with this, to get information on target geometry and conductivity (geoelectrical model) This work presents a methodology to get CDIs over the measurement profile (2-D)...

This paper is in Portuguese. The mosaic of five aerogeophysical surveys flown in the State of Minas Gerais were correlated with the available geological data to define the magnetic-structural framework of southern portion of São Francisco Craton (Figure 1). The data processing consisted in leveling and integration of the blocks from the Brazil-Germ...

This paper is in Portuguese. The main purposes of this study were focused to the processing, leveling and integration of several magnetic airborne geophysical surveys, acquired in the southern part of São Francisco Craton, State of Minas Gerais. To the leveling and integration of the several blocks of data from the Brazil-Germany Geophysical Agreem...

This paper is in Portuguese. This paper presents some results of an extensive processing, interpretation and geological integration campaign of airborne magnetic field data. It comprised data from the sampling of 30.360 linear kilometers of profiles, spaced 2 km apart, covering an area of 54.000 km² in northwest Mato Grosso State (Rio do Sangue Pro...

This paper is in Portuguese. High resolution aeromagnetic airborne survey is used to determinate the tectonic framework from the Porangatu region, NW Goiás. We recognized different crustal blocks and large lineaments that are interpreted as a system of strike slip shear zones. Euler deconvolution method is a potencial tool to define the geometry of...

Afloramentos escassos e um intemperismo acentuado caracterizam o Greenstone Belt Rio das Velhas no sudeste do Brasil. Este artigo sumariza a utilização de dados aerogeofísicos de alta densidade de amostragem aplicados à exploração mineral baseado no realce e na interpretação de dados magnéticos, radiométricos e eletromagnéticos no domínio da freqüê...

Poor outcrop and deep weathering characterize the Rio das Velhas Greenstone Belt in the southeastern from Brazil. This paper summarizes the use of high-density airborne survey for mineral exploration studies based on Interpretation enhancements of magnetic, radiometric and frequency domain electromagnetic data using image-processed methods and an u...

This paper is in Portuguese. The area covered by the Itabira-Ferros Project is located in the State of Minas Gerais Iron Quadrangle and is known for its emerald occurrences and deposits. The area is characterized by green stone belts (Guanhães Complex and Rio das Velhas Supergroup) and paleoproterozoic iron sequences belonging to Minas Series, inse...

This paper is in Portuguese. The area covered by the Itabira-Ferros Project is located in the State of Minas Gerais Iron Quadrangle and is known for its emerald occurrences and deposits. The present study apply geophysical characteristics, using airborne gamma-ray spectrometric data and their integration with geology, to determine probable zones of...

This paper is in Portuguese. This paper reports processing techniques applied to airborne magnetic data to generate themes that could be used as a tool do delimitate the boundaries and the tectonic framework in the northeastern portion of the Borborema Province in NE Brazil. Data processing result in the generation of anomalous magnetic map, residu...

This paper is in Portuguese. This paper reports the processing and interpretation of the airborne geophysical data (MAGNETIC and GAMAESPECTROMETRY) from the Itatira Project (1977). The aerogeophysical themes can be used on the characterization of the tectonic framework of the Ceará central region. The data processing was able to distinguish the inn...

This paper is in Portuguese. This paper deals with a 3D magnetic data (Seridó Project, 1973) interpretation of regional geologic structures (Patos Lineament and João Câmara-Picuí Shear Zone) in Northeast Brazil based on horizontal position and depth for magnetic sources given by Euler deconvolution. Best parameters for Euler deconvolutions were fou...

This paper is in Portuguese. The present paper aim shows the processing of the aerogeophysical data from the Barreiro Project (1976), generating themes than can be used as a tool to suporte geologic mapping in the region of Nova Xavantina-MT, Central Brazil. They include K, U and Th channels images, and a color composition RGB (K:Th:U). Also, anoma...

Abstract It is shown here results of gamma-ray spectrometric data processing from Block 1 of Brasil-Canada Geophysics Project (PGBC), flown between 1975 and 1976. Job was done as part of a more extensive task aiming the integration of the gamma-ray spectrometry processing to others obtained from magnetic, geochemical and geological data for the CM...

Resumo Mostram-se aqui alguns resultados do processamento de dados magnéticos pertencentes ao Bloco 1 do Projeto Geofísico Brasil-Canadá (1975/76). Fez parte de um trabalho bem mais extenso que visou à integração de seus resultados aqueles obtidos de dados gamaespectrométricos, geoquímicos e geológicos visando à modelagem de favorabilidade para mi...

Resumo Mostram-se aqui alguns dos resultados do processamento de dados gamaespectrométricos realizado pela HGeo e pertencentes ao Bloco 1 do Projeto Geofísico Brasil-Canadá (1975/76). Integrou um trabalho bem mais completo focado na integração de seus resultados aqueles obtidos a partir de dados magnetométricos, geoquímicos e geológicos, com vista...

Abstract It is shown here results of magnetic data processing from Block 1 of Brasil-Canada Geophysics Project (PGBC), flown between 1975 and 1976. This task was part of a more extensive job that aimed the integration of the magnetic processing to others obtained from gamma-ray spectrometric, geochemical and geological data for the CMM (Companhia...

SOIL SURVEY BY DC ELECTRICAL RESISTIVITY AND GAMMA-RAY SPECTROMETRY The purpose of this work is to present procedures for reconnaissance of soils, based on DC electrical resistivity measurements and gamma-ray spectrometry. The study area has 5 km 2 and is located in the Jardim Botânico de Brasília (Brazil), an environmental conservation area. In th...

Note: This abstract is on the article text. Abstract AIRBONE GEOPHYSICS APPLIED TO MINERAL EXPLORATION AND GEOLOGICAL MAPPING IN THE SOUTHWEST SECTOR OF THE ORÓS-JAGUARIBE COPPER BELT, NORTHEASTERN BRAZIL Mineral deposits like those of the Cu-Au-U-ETR-Fe-oxides class are commonly associated with hydrothermal alteration zones that are detectable...

Resumo APLICAÇÃO DE DADOS AEROGEOFÍSICOS À EXPLORAÇÃO MINERAL EM TERRENOS IRREGULARMENTE EXPOSTOS DO GREENSTONE BELT RIO DAS VELHAS A abordagem geofísica utilizada neste trabalho consiste no processamento e realce de dados geofísicos, os quais puderam ser interpretados com ênfase no contexto geológico. O raciocínio usado é que, em exploração, não s...

CHARACTERIZATION OF THE ARCHEAN ORTOGNAISSE COMPLEXES OF GOIÁS BY AIRBORNE GAMMA-RAY SPECTROMETRY The Archean terranes of Goiás, Central Brazil, consist of 5 greenstone belts, and four complexes and one block of orthogneisses. The lithologic similarity among the complexes, inspite of their diferent ages, contribute significantly for their delimitat...

As part of a research program to develop gravity interpretation tools that can be merged with seismic techniques, a full 3-D complex structural inversion scheme for (possibly multibody) polyhedral models has been developed. The forward modeling algorithm was adopted from previous work. Because the inverse problem is generally very ill posed, severa...

A gravity survey was carried out in the central and northern state of Goías portions, covering an area of 9000 km 2 of granite-greenstone belt rock associations. Using a fixed density of 2.67 g/cm 3 and removing a second-degree trend surface for modeling and inversion, we determined the residual anomalies. Each anomaly was associated to well-known...

Abstract Because its geological complexity and mineral potential, the central region of Brazil has been calling attention in the last decades. The region is placed in the Tocantins Structural Province showing Archaean greenstone belts (Goiás City, Faina, Crixás, Guarinos and Pilar de Goiás), granite-gneiss terrenes and a neoproterozoic magmatic arc...

Abstract The geological complexity of the central region of Brazil is a frequent subject in the Brazilian geoscientific discussions. This complexity can be verified by the amount of published papers. The large amount of information is an indication of the lack of standardization of the various geological interpretation products: the geological maps...

Abstract Extensive geophysical data processing of magnetic and gamma-ray spectrometric data from the Juruena – Teles Pires airborne survey supplied information supporting geologic interpretation of the area. Na integrated map, obtained from a qualitative analysis of the geophysical information, brought new insight to the geological knowledge of thi...

Abstract Gravity information is normally gathered with seismic data in petroleum exploration. As such, it is presented here a way to enhance the contribution of gravity fields not only in the prospecting effort but also in hydrocarbon reservoir management. It deals with a full 3D model inversion of gravity data, and is designed to improve the final...

Abstract Gravity information is normally gathered with seismic data in petroleum exploration. As such, it is presented here a way to enhance the contribution of gravity fields not only in the prospecting effort but also in hydrocarbon reservoir management. It deals with a full 3D model inversion of gravity data, and is designed to improve the fina...

Abstract Analytical signal representation of the anomalous magnetic field has the advantage of produce a transformation whose anomalies are centered over the borders of their magnetic anomalous sources. As such, it allows an easier way of depicting the position of these sources a task sometimes not easily done on the magnetic anomalous field repre...

Abstract Curie point represents a temperature above which a material loses its magnetic properties. The Interpreted Curie Surface is an attempt to map a surface within the Earth’s crust whose depth represents a limit bellow which the above behavior happens with geologic magnetic material (chiefly magnetite). Therefore the variations in this depth m...

This paper presents strategies for integration of multi-source data using the aerogeophysical and remote sensing surveys performed within the area covered by the Rio das Velhas Project, in Minas Gerais. Among the techniques employed we highlight the following: (i) the EDICROM-RM, which can portray, in a single product, the magnetic relief using the...