Tin Tarabine and its surrounding areas (central Hoggar), a key region for lithological and structural investigation by airborne magnetic data and gamma ray spectrometry

2019 ◽  
Author(s):  
Kawther Araïbia ◽  
Massinissa Amara ◽  
Kamel Amri ◽  
Abderrahmane Bendaoud ◽  
Chakib Harouz
Keyword(s):  
Structural Investigation ◽  
Gamma Ray ◽  
Magnetic Data ◽  
Gamma Ray Spectrometry ◽  
Surrounding Areas ◽  
Airborne Magnetic

scholarly journals INTERPRETATION OF RADIOMETRIC RATIOS AND MAGNETIC ANOMALIES FROM MORRO FEIO ULTRAMAFIC COMPLEX, CENTRAL-WESTERN BRAZIL

2019 ◽  
Vol 37 (3) ◽  
pp. 309
Author(s):  
Adolfo Silva ◽  
Tiago Duque ◽  
Felipe Alves
Keyword(s):  
Gamma Ray ◽  
Magnetic Anomalies ◽  
Primary Sources ◽  
Magnetic Data ◽  
Gamma Ray Spectrometry ◽  
Mineral Research ◽  
Magnetic Structures ◽  
Relative Enrichment ◽  
Ultramafic Complex ◽  
Processing Techniques

ABSTRACTThis study was performed to identify magnetic structures in depth and radiometric responses within and around Morro Feio Ultramafic Complex (MFUC) from the airborne geophysical (gamma–ray spectrometry and magnetic) data. Using processing techniques and profiles analysis, we have found eight gamma–ray spectrometry signatures and twenty–seven magnetic anomalies. The radiometric signatures are basically characterized by a K and eU relative enrichment in detriment eTh, with two of these signatures also characterized by K relative enrichment in detriment eU. Based on published works, we have interpreted the radiometric responses may be from serpentinite and possible areas with hydrothermal alterations. Regarding the magnetic anomalies, we concluded that the shallowest may be the magnetic responses of dikes, contact zones and other structures, while the deepest have sources with more complex geometries and are concentrated in central–western of MFUC, where the participation of Pt is larger. In this aspect, our results reinforce the arguments favorable to existence of Pt, Cr and Ni primary sources in depth.Keywords: mineral research, airborne geophysical, serpentinites, hydrothermal alteration.RESUMOEste estudo foi realizado com o objetivo de identificar estruturas magnéticas em profundidade e respostas radiométricas dentro e no entorno do Complexo Ultramáfico de Morro Feio (CUMF) a partir de dados aerogeofísicos (gamaespectrometria e magnetometria aérea). Utilizando técnicas de processamento e análise de perfis, encontramos oito assinaturas gamaespectrométrica e vinte e sete anomalias magnéticas. As assinaturas radiométricas caracterizam–se basicamente por um enriquecimento relativo de K e eU em detrimento eTh, com duas dessas assinaturas também sendo caracterizadas pelo enriquecimento relativo de K em detrimento eU. Com base em trabalhos publicados, interpretamos que as respostas radiométricas podem ser em virtude do serpentinito e possíveis áreas com alterações hidrotermais. Com relação às anomalias magnéticas, concluímos que as mais rasas podem ser as respostas magnéticas de diques, zonas de contato e outras estruturas, enquanto que as mais profundas possuem fontes com geometrias mais complexas e se concentram no centro–oeste do CUMF, onde a participação de Pt é maior. Neste aspecto, nossos resultados reforçam os argumentos favoráveis a existência de fontes primárias de Pt, Cr e Ni em profundidade.Palavras-chave: pesquisa mineral, aerogeofísica, serpentinitos, alteração hidrotermal.

Characterization of 41Ar production in air at a PET cyclotron facility

2017 ◽  
Vol 32 (17) ◽  
pp. 1740014 ◽  
Author(s):  
Gianfranco Cicoria ◽  
Francesco Cesarini ◽  
Angelo Infantino ◽  
Sara Vichi ◽  
Federico Zagni ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Ventilation System ◽  
Emission Tomography ◽  
Gamma Ray Spectrometry ◽  
Maximum Value ◽  
Positron Emission ◽  
Before And After ◽  
Surrounding Areas ◽  
Total Effective Dose

In the production of Positron Emission Tomography (PET) nuclides at a medical cyclotron facility [Formula: see text]Ar (T[Formula: see text] = 109.34 m) is produced by the activation of air due to the neutron flux, according to the [Formula: see text]Ar(n, [Formula: see text])[Formula: see text]Ar reaction. In this work, we describe a relatively inexpensive and readily reproducible methodology of air sampling that can be used for quantification of [Formula: see text]Ar during the routine production of PET nuclides. We report the results of an extensive measurement campaign in the cyclotron bunker and in the ducts of the ventilation system, before and after final filtering of the extracted air. Air Samples were analyzed using a gamma-ray spectrometry system equipped with HPGe detector, with proper correction of the efficiency calibration to account for the samples density. The results of measurement were then used to evaluate the Total Effective Dose (TED) to the population living in the surrounding areas, due to routine emissions in the operation of the cyclotron. The average [Formula: see text]Ar saturation yield per one liter of air emitted in the environment resulted to be (0.044 ± 0.007) Bq/([Formula: see text]A ⋅ dm3). The maximum value of TED for the critical group of the population, even considering an overestimated workload, was less than 0.19 [Formula: see text]Sv/year, well below the level of radiological relevance.

The role of airborne geophysics for detecting hydrocarbon microseepages and related structural features: The case of Remanso do Fogo, Brazil

Geophysics ◽  
2012 ◽  
Vol 77 (2) ◽  
pp. B35-B41 ◽  
Author(s):  
Julia B. Curto ◽  
Augusto C.B. Pires ◽  
Adalene M. Silva ◽  
Álvaro P. Crósta
Keyword(s):  
Gamma Ray ◽  
Sedimentary Cover ◽  
Structural Features ◽  
Magnetic Data ◽  
Gamma Ray Spectrometry ◽  
Horizontal Gradient ◽  
Near Surface ◽  
Residual Values ◽  
Basement Structures ◽  
New Occurrences

The first direct indication of hydrocarbon occurrence in Remanso do Fogo area (Minas Gerais State, Brazil) was the existence of microseepages. However, Quaternary sedimentary cover in the area made the identification of new occurrences and associated controlling structures quite difficult. This study investigated the spatial distribution of hydrocarbon related gases in shallower to intrasedimentary depths in Remanso do Fogo area, using airborne gamma-ray spectrometry and magnetic data. The geophysical data were processed using techniques designed to suppress the influence of regional geological signatures. Known and possible new occurrences of microseepages were detected by mapping low residual potassium values and high uranium residual values in relation to potassium, termed as DRAD values, which resulted from the subtraction of potassium from uranium residual values, using a Thorium (Th)-normalizing approach. The validation of these occurrences was done based on existing gas geochemistry data in the soil. For the magnetic data, the amplitude of the analytic signal, combined with the total horizontal gradient of the subtraction between the 1200- and 400-meter upward continuations, enhanced the northwest–southeast and east–west magnetic lineaments, which are partially related to the microseepages and the drainage of the area. The distinction of near-surface and deep signatures also allowed the general identification of intrasedimentary and basement structures, which are potentially controlling the occurrences of seepages in the area.

scholarly journals RECOGNITION OF GOLD MINERALIZATION FAVORABILITY ZONES THROUGH AIRBORNE GAMMA-RAY SPECTROMETRY AND MAGNETOMETRY IN BRUSQUE AND BOTUVERÁ REGION, SOUTHERN BRAZIL

2018 ◽  
Vol 36 (3) ◽  
pp. 1 ◽  
Author(s):  
Bruno Macchioni Pereira ◽  
Francisco Jose Fonseca Ferreira
Keyword(s):  
Hydrothermal Alteration ◽  
Gamma Ray ◽  
Gold Mineralization ◽  
Shear Zones ◽  
Magnetic Data ◽  
Gamma Ray Spectrometry ◽  
Southern Brazil ◽  
Santa Catarina ◽  
Index Overlay ◽  
Primary Gold

ABSTRACT. The northeastern portion of Santa Catarina State, southern Brazil, bears important primary gold mineralization associated with granitic intrusions with potassic and phyllic hydrothermal alteration zones and a phase shear zone reactivation. Airborne radiometric and magnetic data were applied in the study area through the use of gamma-ray spectrometry (Total Count, K, eTh and eU) and suggestive parameters of hydrothermal alteration as Kd, Ud and F, in association with geological units, while magnetometry (RTP, THDR, TDR and Signum Transform) was applied in the definition of the structural framework. Geophysical data was interpreted and integrated to geological information, such as lithologic units, structures, shear zones and gold mineralization, using the knowledge driven and index overlay methods in order to define favorable targets. The geophysical and geological data exhibit good correlation, as seen in the gamma-ray spectrometric domains and magnetic lineaments, and the favorability map shows important target areas for primary gold mineralization. It was possible to observe in the geophysical maps that shear zones and faults have more influence in the occurrences than potassic and phyllic hydrothermal alteration related to granitic intrusions.Keywords: geophysical exploration, knowledge-driven, Dom Feliciano Belt.RESUMO. A porção nordeste do estado de Santa Catarina, sul do Brasil, possui importantes mineralizações auríferas primárias associadas a intrusões graníticas com zonas de alteração hidrotermal potássica e fílica e posterior fase de reativação de zonas de cisalhamento. Dados radiométricos e magnéticos aerogeofísicos foram aplicados na área de estudo através do uso de gamaespectrometria (Contagem Total, K, eTh e eU) e parâmetros sugestivos de alteração hidrotermal como Kd, Ud e Parâmetro F. Em associação com unidades geológicas, enquanto a magnetometria (RTP, GHT, ISA e Signum Transform) foi aplicada na definição do arcabouço estrutural. Os dados geofísicos foram interpretados e integrados às informações geológicas, como unidades litológicas, estruturas, zonas de cisalhamento e mineralizações de ouro, utilizando os métodos knowledge-driven e index overlay para definir alvos favoráveis. Os dados geofísicos e geológicos apresentam boa correlação, como visto nos domínios espectrométricos de raios gama e lineamentos magnéticos, e o mapa de favorabilidade mostra áreas-alvo importantes para a mineralização de ouro primária. Foi possível observar nos mapas geofísicos que as zonas de cisalhamento e as falhas têm mais influência nas ocorrências do que as zonas de alteração hidrotermal potássica e fílica relacionada às intrusões graníticas.Palavras-chave: exploração geofísica, knowledge-driven, Cinturão Dom Feliciano.

Gamma-Ray Spectrometric Analysis of Some Trace Elements in the Human Articular Disc of the Mandible

1963 ◽  
Vol 03 (02) ◽  
pp. 175-182 ◽  
Author(s):  
Bo Bergman ◽  
Rune Söremark
Keyword(s):  
Trace Elements ◽  
Neutron Activation ◽  
Quantitative Data ◽  
Thermal Neutron Flux ◽  
Gamma Ray ◽  
Dry Weight ◽  
Gamma Ray Spectrometry ◽  
Spectrometric Analysis ◽  
Articular Disc ◽  
Group Separation

SummaryBy means of neutron activation and gamma-ray spectrometry the concentrations in the human mandibular articular disc of the following elements have been determined: Na, Mn, Cu, Zn, Rb, Sr, Cd, W, and Au. The discs were obtained at necropsy from seven men and nine women, ranging in age from 56 to 71 years.The activation was carried out in a thermal neutron flux of about 1.7 XlO12 neutrons × cm−2 × sec.−1 for about 20 hours. A chemical group separationwas performed before the gamma-ray spectrometry. Quantitative data based on the dry weight of the cartilage samples were obtained by comparing the photo-peak area of the identified elements with those of appropriate standards.

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