Investigation of the Goiás Alkaline Province, Central Brazil: Application of gravity and magnetic methods

Dutra, Alanna C.; Marangoni, Yára Regina; Junqueira-Brod, Tereza Cristina

doi:10.1016/j.jsames.2011.06.004

Cited by 34 publications

(28 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The distribution of density in-depth shows that the intrusion of Córrego dos Bois (anomaly #5) extends from the surface to almost 10 km in-depth, with a density contrast of 0.4 g/cm 3 that corresponds to a density value of 3.07 g/cm 3 ; this value is consistent with the density values in the literature for the same rocks in the area (Dutra et al, 2012;Ahrens & Johnson, 1995). Results from the 2.5D magnetic modeling (Fig.…”

Section: Gravity and Magnetic Forward Modelingsupporting

confidence: 88%

“…3D density distribution obtained spherical mass distribution usually with denser material at the center. Like the results from GAP (Dutra et al, 2012) the density distribution form Kola are limited to the upper crust. Dindi & Swain (1988) modeled the Jombo Hill alkaline complex, Kenya, by a 3D inversion of gravity and magnetic data.…”

Section: Introductionsupporting

confidence: 65%

“…It is expected large amplitude magnetic and gravity anomalies. The geophysical signature of part of the north section of the GAP has already been studied (Dutra & Marangoni, 2009;Dutra et al, 2012), while the central and south sections are still in the need of geophysical modeling. The north section displays large postive Bouguer anomalies with amplitudes varying from +20 to +70 mGal.…”

Section: Geological Background and Previous Workmentioning

confidence: 99%

“…The magnetic anomalies show all normal direction of magnetization, with maximum and minimum amplitudes varying from +6000 nT to -5000 nT. The models for anomalies in the north section of the GAP resulted in subsurface distribution of mass and magnetic material whose geometrical shape resembles spheres or short cylinders (Dutra & Marangoni, 2009;Dutra et al, 2012). The spatial distribution of mass has been interpreted as magma chambers, some of them crop out and some are covered by Quaternary sediments of Araguaia River.…”

Section: Geological Background and Previous Workmentioning

confidence: 99%

See 3 more Smart Citations

Gravity and Magnetic Integrated Data Interpretation of the Corrégo Dos Bois Complex, Goiás Alkaline Province, Central Brazil

Marangoni¹,

Zhang²,

Ferreira³

2016

Rev. Bras. Geof.

View full text Add to dashboard Cite

ABSTRACT. Previous studies carried out in some alkaline provinces around Paraná Basin, Brazil, show that most of the alkaline intrusions are related to high magnetic and gravity anomalies. In this study, both magnetic and gravity data are used to explore some of the alkaline intrusions of the Goiás Alkaline Province in Goiás State, near the northern Paraná Basin border. The total gradient and the normalized anisotropy variance methods were applied to detect the intrusions' locations; they show a strong correlation between outcrops and sources for the main bodies. Then, by combining the 3D inverted magnetization contrast from the magnetic data and the 2.5Dforward model from both the gravity and magnetic data, it was possible to set a mass distribution model for the intrusion of Córrego dos Bois. The results show that this intrusion extends from the surface to almost 10 km in depth, with a density contrast of 0.4 g/cm 3 corresponding to a density value of 3.2 g/cm 3 , which is coherent with those shown in the literature for the rocks in the area. Magnetic inversion resulted in anomalies that are very similar but circa 200 nT lower than the observations at the positive lobe and no significant variation at the negative lobe. The magnetic source has 20 A/m for magnetization.Keywords: Brazilian alkaline, gravity anomaly, magnetic anomaly, inversion method, forward modeling. RESUMO.Estudos anteriores em algumas províncias alcalinas ao redor da Bacia do Paraná, Brasil, indicaram que a maioria das intrusões alcalinas apresentam anomalias magnéticas de campo total de forte intensidade e anomalias Bouguer usualmente caracterizadas por altos gravimétricos. Neste estudo, dados de campos magnético e gravimétrico são utilizados para explorar algumas das intrusões alcalinas da Província Alcalina de Goiás, no Estado de Goiás, próximoà borda norte da Bacia do Paraná. Os métodos de gradiente total e variância normalizada da anisotropia foram aplicados para determinar a localização das intrusões, e mostraram boa correlação entre os afloramentos e as fontes de anomalia para os corpos principais. Combinando os resultados da inversão 3D do contraste de magnetização dos dados magnéticos com os modelos diretos 2,5D de dados gravimétricos e magnéticos foi possível estabelecer um modelo de distribuição de massa para a intrusão de Córrego dos Bois. O resultado mostra que essa intrusão se estende da superfície até cerca de 10 km em profundidade, com um contraste de densidade de 0,4 g/cm 3 , correspondendo a um valor de densidade de 3,2 g/cm 3 , queé um valor de densidade coerente com os valores publicados na literatura para as rochas presentes naárea.A inversão dos dados magnéticos daárea de estudo resultou em anomalias muito semelhantes, com amplitudes positivas cerca de 200 nT menores que a observada no lobo positivo, mas com pouca variação na amplitude das porções negativas das anomalias. A fonte magnética apresentou uma magnetização de 20 A/m. Palavras-chave: alcalinas brasileiras, anomalia gravimétrica, anomalia magnética, método inver...

show abstract

Section: Gravity and Magnetic Forward Modelingsupporting

confidence: 88%

Section: Introductionsupporting

confidence: 65%

Section: Geological Background and Previous Workmentioning

confidence: 99%

Section: Geological Background and Previous Workmentioning

confidence: 99%

See 2 more Smart Citations

Gravity and Magnetic Integrated Data Interpretation of the Corrégo Dos Bois Complex, Goiás Alkaline Province, Central Brazil

Marangoni¹,

Zhang²,

Ferreira³

2016

Rev. Bras. Geof.

View full text Add to dashboard Cite

show abstract

“…The technique was applied to the upward continued aeromagnetic anomaly data to determine depth of ring complexes and folds in the study area. Structural index 2, which represents cylindrical shaped body, was chosen because magnetic field of alkaline intrusion (ring complex) can be inferred with the body [8] [24]. This index was ran with window lengths of 10, 15 and 20 and a combination of 20 × 20 window size with the index was used for the interpretation because it gave the tightest cluster of solutions that fitted the expected geological structure [29].…”

Section: Depth To Structural Featuresmentioning

confidence: 99%

An Interpretation of Structures from the Aeromagnetic Field over a Region in the Nigerian Younger Granite Province

Raimi¹,

Dewu²,

Süle³

2014

IJG

View full text Add to dashboard Cite

An interpretation of high resolution aeromagnetic data was carried out to provide new information about the study area. Located between latitude 10˚30'N and 11˚00'N and longitude 8˚30'E and 9˚00'E, the interpretation revealed previously unknown folds and magnetic anomaly with a signature that is similar to those associated with ring complexes in the study area but without the surface manifestation that is associated with the complexes. Qualitatively interpreted as unexposed ring complex, the magnetic anomaly is underlain by cross-over of major lineaments; implying presence of weak zone that probably allowed the volcanic eruption that initiated the emplacement of the source of the anomaly. A depth that ranges from outcrop to 1200 m and from outcrop to 1800 m is respectively suggested for the unexposed ring complex and folds by the Euler deconvolution results.

show abstract

Existence of a possible subsurface ring complex in the northwestern part of the Nigerian Younger Granite province: a contribution from aeromagnetic and remote sensing data

2014

View full text Add to dashboard Cite

The study area lies within the north-western part of the Nigerian Younger Granite province. It is bounded by latitude 10°30′N and 11°00′N and longitude 8°00′E and 9°00′E. Previous geological and geophysical studies that were carried out in the study area focused mainly on the ring complexes with surface exposure while nothing is known about those without the surface exposure. This has resulted in gap in geo-scientific knowledge which this study aimed to fulfill. First vertical derivative (FVD) and Euler deconvolution of the aeromagnetic data along with processed DEM were used to achieve this purpose. Results of the interpretation revealed a magnetic anomaly, almost circular in shape, with characteristics that are similar to the anomalies that spatially coincide with the prominent ring complexes but without the outcrops that are associated with the complexes. This anomaly is interpreted to be an unexposed ring. Lineaments revealed by the results are mainly oriented in the E-W, NE-SW and NW-SE. The lineaments in the NE-SW and its conjugate are the most developed lineament system. Presence of ring complexes on and along the lineaments favours the opinion that the emplacement sites of the complexes are influenced by the reactivated Pan-African shear zones and transcurrent faults. In particular, the cross-over of major lineaments at the nonoutcropping anomaly may suggest a very weak zone that probably allowed the volcanic eruption that initiated the emplacement of the unexposed ring complex. Results of the Euler deconvolution suggest a cylindrical-like body for the unexposed ring complex, which is consistent with pluton geometry, and a depth that range from outcrop to 1,200 m for it.

show abstract

Investigation of the Goiás Alkaline Province, Central Brazil: Application of gravity and magnetic methods

Cited by 34 publications

References 28 publications

Gravity and Magnetic Integrated Data Interpretation of the Corrégo Dos Bois Complex, Goiás Alkaline Province, Central Brazil

Gravity and Magnetic Integrated Data Interpretation of the Corrégo Dos Bois Complex, Goiás Alkaline Province, Central Brazil

An Interpretation of Structures from the Aeromagnetic Field over a Region in the Nigerian Younger Granite Province

Existence of a possible subsurface ring complex in the northwestern part of the Nigerian Younger Granite province: a contribution from aeromagnetic and remote sensing data

Contact Info

Product

Resources

About