scholarly journals Magnetic data evidence of a likely new alkaline intrusion at Canoas beach, Ponta Grossa Arch Alkaline Province, southern Brazil

2018 ◽  
Author(s):  
F.J.F. Ferreira ◽  
L.S.A. Szameitat ◽  
L.G. Castro ◽  
V.A.F. Silva ◽  
J.D. Weihermann
Keyword(s):  
Magnetic Data ◽  
Southern Brazil ◽  
Alkaline Intrusion

scholarly journals Comparison between Signum transform and Euler deconvolution in magnetic data of the Paranaguá Terrane, southern Brazil

2016 ◽  
Author(s):  
Jessica D. Weihermann ◽  
Francisco J. F. Ferreira ◽  
Saulo P. Oliveira ◽  
Leonardo F. Cury
Keyword(s):  
Magnetic Data ◽  
Southern Brazil ◽  
Euler Deconvolution

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.

Validation of a screening instrument for postpartum depression in Southern Brazil

2009 ◽  
pp. 1-11
Author(s):  
Carlos Zubaran ◽  
Katia Foresti ◽  
Marina Verdi Schumacher ◽  
Aline Luz Amoretti ◽  
Lucia Cristina Muller ◽  
...  
Keyword(s):  
Postpartum Depression ◽  
Screening Instrument ◽  
Southern Brazil

LATE QUATERNARY GEOLOGICAL HISTORY OF RIO GRANGE DO SUL COASTAL PLAIN, SOUTHERN BRAZIL

2000 ◽  
Vol 30 (3) ◽  
pp. 474-476 ◽  
Author(s):  
LUIZ JOSÉ TOMAZELLI ◽  
SÉRGIO REBELLO DILLENBURG ◽  
JORGE ALBERTO VILLWOCK
Keyword(s):  
Coastal Plain ◽  
Late Quaternary ◽  
Geological History ◽  
Southern Brazil ◽  
History Of

Cyclone Bomb hits Southern Brazil in 2020

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Ricardo Gobato ◽  
Alireza Heidari
Keyword(s):  
High Pressure ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Satellite Images ◽  
The State ◽  
Southern Brazil ◽  
Santa Catarina ◽  
High Area ◽  
South Of Brazil ◽  
Rapid Drop

An “explosive extratropical cyclone” is an atmospheric phenomenon that occurs when there is a very rapid drop in central atmospheric pressure. This phenomenon, with its characteristic of rapidly lowering the pressure in its interior, generates very intense winds and for this reason it is called explosive cyclone, bomb cyclone. With gusts recorded of 116 km/h, atmospheric phenomenon – “cyclone bomb” (CB) hit southern Brazil on June 30, the beginning of winter 2020, causing destruction in its influence over. One of the cities most affected was Chapecó, west of the state of Santa Catarina. The satellite images show that the CB generated a low pressure (976 mbar) inside it, generating two atmospheric currents that moved at high speed. In a northwest-southeast direction, Bolivia and Paraguay, crossing the states of Parana and Santa Catarina, and this draft that hit the south of Brazil, which caused the destruction of the affected states.  Another moving to Argentina, southwest-northeast direction, due to high area of high pressure (1022 mbar). Both enhanced the phenomenon.

An Augmented Iteratively Re-weighted and Refined Least Squares Method for lp Minimization Problem in Inverse Modeling of Potential Field Magnetic Data

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Maysam Abedi
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Least Squares ◽  
Minimization Problem ◽  
Potential Field ◽  
Field Data ◽  
Least Squares Method ◽  
Porphyry Copper ◽  
Magnetic Data ◽  
Magnetic Field Data

The presented work examines application of an Augmented Iteratively Re-weighted and Refined Least Squares method (AIRRLS) to construct a 3D magnetic susceptibility property from potential field magnetic anomalies. This algorithm replaces an lp minimization problem by a sequence of weighted linear systems in which the retrieved magnetic susceptibility model is successively converged to an optimum solution, while the regularization parameter is the stopping iteration numbers. To avoid the natural tendency of causative magnetic sources to concentrate at shallow depth, a prior depth weighting function is incorporated in the original formulation of the objective function. The speed of lp minimization problem is increased by inserting a pre-conditioner conjugate gradient method (PCCG) to solve the central system of equation in cases of large scale magnetic field data. It is assumed that there is no remanent magnetization since this study focuses on inversion of a geological structure with low magnetic susceptibility property. The method is applied on a multi-source noise-corrupted synthetic magnetic field data to demonstrate its suitability for 3D inversion, and then is applied to a real data pertaining to a geologically plausible porphyry copper unit.  The real case study located in  Semnan province of  Iran  consists  of  an arc-shaped  porphyry  andesite  covered  by  sedimentary  units  which  may  have  potential  of  mineral  occurrences, especially  porphyry copper. It is demonstrated that such structure extends down at depth, and consequently exploratory drilling is highly recommended for acquiring more pieces of information about its potential for ore-bearing mineralization.

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