Presentation of magnetic anomaly map data by stereo projection of magnetic shadowgrams

1985 ◽  
Vol 22 (2) ◽  
pp. 311-314 ◽  
Author(s):  
John Broome ◽  
Réjean Simard ◽  
Dennis Teskey
Keyword(s):  
Magnetic Anomaly ◽  
Geological Mapping ◽  
Geological Survey ◽  
Magnetic Data ◽  
Stereo Pair ◽  
Magnetic Intensity ◽  
Fine Detail ◽  
Anomaly Map ◽  
Map Data ◽  
Shaded Relief

Coloured magnetic maps published at the 1:1 000 000 scale by the Geological Survey of Canada have been found to be useful aids in support of regional geological mapping and compilation projects. However, because of the quantization into colour intervals, some of the fine detail contained in the original magnetic data is lost. These smaller features can be brought out quite effectively with the shaded relief technique, although there is an attendant loss of amplitude information, which can be recovered by means of stereo-shadowgrams. A second shadowgram is produced by offsetting the original shadowgram by an amount proportional to the magnetic intensity of each data point and then the offset and original shadowgrams are viewed as a stereo pair. An example of the effectiveness of these techniques is the detail that can be seen on the shadowgrams and stereo-shadowgrams for the Lockhart River (IMW NP 12/13) and the Thelon River (IMW NQ 12/13/14) map sheets.

scholarly journals PEMODELAN BAWAH PERMUKAAN MANIFESTASI MINERAL DENGAN METODE GEOMAGNETIK DAERAH PACITAN JAWA TIMUR

KURVATEK ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 25-33
Author(s):  
Fatimah Fatimah
Keyword(s):  
Image Data ◽  
Geological Structure ◽  
Magnetic Data ◽  
Magnetic Intensity ◽  
Magmatic Arc ◽  
The North ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Extensional Structure ◽  
Anomaly Map

Tulakan Subdistrict, Pacitan Regency, East Java Province. This area is part of the Southern Mountain Zone of East Java, which is the Sunda-Banda magmatic arc of Oligo-Miocene age, where there are alterations and indications of valuable ore minerals. Field magnetic data is taken in an area of 1 x 1 km, with the looping method on the grid trajectory within 200 x 100 m. Then, magnetic data correction and data processing were carried out with Oasis Montaj. From the magnetic anomaly map, the value of high magnetic intensity in the southern part is fresh (intrusive) andesit-dasitic rock as host rock which causes alteration, in the middle has a low magnetic intensity value which is in the direction of the relatively NE-SW river direction, whereas in the north with high intensity is fresh andesite lava. From the image data, it can be seen that the straightness pattern of the geological structure which is dominated by the extensional structure with the direction of NE-SW and E-W is the main trap of epithermal veins carrying ore mineralization mainly Cu, Pb in the study area.

A new look at Belgian aeromagnetic and gravity data through image-based display and integrated modelling techniques

1993 ◽  
Vol 130 (5) ◽  
pp. 583-591 ◽  
Author(s):  
B. C. Chacksfield ◽  
W. De Vos ◽  
L. D'Hooge ◽  
M. Dusar ◽  
M. K. Lee ◽  
...  
Keyword(s):  
Large Scale ◽  
Gravity Data ◽  
Bouguer Anomaly ◽  
Digital Processing ◽  
Integrated Modelling ◽  
Magnetic Data ◽  
Gravity Gradient ◽  
The North ◽  
Anomaly Map ◽  
Shaded Relief

AbstractDigital processing and image-based display techniques have been used to generate contour and shaded-relief maps of Belgian aeromagnetic data at a scale of 1:300000 for the whole of Belgium. These highlight the important anomalies and structural trends, particularly over the Brabant Massif. North and vertically illuminated shaded-relief plots, enhanced structural belts trending west–east to northwest–southeast in the Brabant Massif and west–east to southwest–northeast in the core of the Ardennes. The principal magnetic lineaments have been identified from the shaded-relief plots and tentatively correlated to basement structures. Most short lineaments are correlated with individual folds while the more extensive lineaments are correlated with large scale fault structures. Magnetic highs within the Brabant Massif are attributed to folded sediments of the Tubize Group. The magnetic basement in the east of Belgium is sinistrally displaced to the north by an inferred deep NNW–SSE crustal fracture. The Bouguer anomaly map of Belgium identifies the Ardennes as a negative area, and the Brabant Massif as a positive area, with the exception of a WNW–trending gravity low in its western part. The southern margin of the Brabant Massif is defined by a steep gravity gradient coincident with the Faille Bordiere (Border Fault). Trial modelling of the gravity and magnetic data, carried out along profiles across the Brabant and Stavelot massifs, has identified probable acid igneous intrusions in the western part of the Brabant Massif, and a deep magnetic lower density body underlying the whole Ardennes region, which is thought to be a distinctive Precambrian crustal block.

scholarly journals Shaded relief presentation of the magnetic anomaly map of Canada

1989 ◽  
Author(s):  
D J Teskey ◽  
P J Hood ◽  
S D Dods
Keyword(s):  
Magnetic Anomaly ◽  
Anomaly Map ◽  
Shaded Relief

Comparison of MAGSAT and low-level aeromagnetic data over the Canadian Shield: implications for GRM

1985 ◽  
Vol 22 (9) ◽  
pp. 1241-1247 ◽  
Author(s):  
J. Arkani-Hamed ◽  
D. W. Strangway ◽  
D. J. Teskey ◽  
P. J. Hood
Keyword(s):  
Magnetic Anomaly ◽  
Canadian Shield ◽  
Geological Mapping ◽  
Aeromagnetic Data ◽  
Research Mission ◽  
Geological Features ◽  
Order Of Magnitude ◽  
Band Limited ◽  
Anomaly Map ◽  
The One

Band-limited magnetic anomalies over the Canadian Shield, for wavelengths of ~500–2200 km, derived from the magnetometer satellite (MAGSAT) data correlate peak for peak with the corresponding anomalies derived from the aeromagnetic data. This suggests that the anomalies detected by MAGSAT are physically meaningful. A new potential field satellite, Geopotential Research Mission (GRM), has been proposed to fly at about 160 km altitude. The magnetic anomaly map that can be derived from the GRM data is expected to have a resolution about an order of magnitude higher than the one derived from MAGSAT data. A magnetic anomaly map of the Canadian Shield, which is expected to derive from the GRM data, is shown based on the aeromagnetic data. The map delineates many major geological features quite clearly and illustrates the importance of the GRM mission for global geological mapping.

U.S. National Magnetic Anomaly Survey Specifications Workshop Report

Geophysics ◽  
1979 ◽  
Vol 44 (5) ◽  
pp. 991-992
Author(s):  
William J. Hinze
Keyword(s):  
Magnetic Anomaly ◽  
North American ◽  
Executive Committee ◽  
Ad Hoc ◽  
Magnetic Data ◽  
Aeromagnetic Data ◽  
Workshop Report ◽  
The North ◽  
Anomaly Map ◽  
The U.S

The National Magnetic Anomaly Map (NMAM) Committee, which was formed as an ad hoc committee in 1975 by the SEG Executive Committee, has recommended a multistage program for improving the aeromagnetic data of the U.S. On behalf of the geoscience community, the committee and the U.S. Geological Survey are currently engaged in the preparation of a photo‐composite map of the U.S. derived from publicly available data plus regional magnetic data contributed from the private sector. This map is at present being compiled and is to be pulished by the U.S.G.S. at a scale of [Formula: see text]. Eventually, utilizing this map, the committee plans to assist in the preparation of a North American magnetic anomaly map to supplement the North American tectonic map and the proposed continental gravity anomaly map.

The World Digital Magnetic Anomaly Map: version 2.1

2020 ◽  
Author(s):  
Jerome Dyment ◽  
Yujin Choi ◽  
Vincent Lesur ◽  
Andreina Garcia-Reyes ◽  
Manuel Catalan ◽  
...  
Keyword(s):  
Magnetic Anomaly ◽  
International Association ◽  
Magnetic Data ◽  
International Polar Year ◽  
The World ◽  
International Polar ◽  
Geological Map ◽  
Version 2.0 ◽  
Anomaly Map ◽  
The Antarctic

<p>The World Digital Magnetic Anomaly Map (WDMAM) is an initiative of the IAGA (International Association of Geomagnetism and Aeronomy) supported by the CGMW (Commission for the Geological Map of the World) of UNESCO. The second version was released in 2015 (Dyment et al., 2015; Lesur et al., 2016), and mandate was given to the authors to update this version 2.0 using the same methodology as often as newly available data would make it necessary. Five better datasets justify the preparation and release of version 2.1: (1) the complete digital aeromagnetic map of Brasil made available to CGMW by Agência Nacional do Petróleo, Gás Natural e Biocombustíveis; (2) an improved version of the aeromagnetic map of Russia prepared at VSEGEI; (3) the second version of the Antarctic Digital Magnetic Anomaly maP (ADMAP; Golynsky et al., 2018) which construction results from a remarkable international effort during and after the Second International Polar Year; (4) a new map of the Caribbean plate and Gulf of Mexico resulting from the compilation and re-processing of existing marine and aeromagnetic data in the area (Garcia, 2018); and (5) a new compilation of marine magnetic data worldwide. The new map shows significant improvements over the previous versions and will be shortly available at wdmam.org.</p>

Magnetic anomaly map of the world: merging satellite, airborne, marine and ground-based magnetic data sets

2007 ◽  
Vol 260 (1-2) ◽  
pp. 56-71 ◽  
Author(s):  
Kumar Hemant ◽  
Erwan Thébault ◽  
Mioara Mandea ◽  
Dhananjay Ravat ◽  
Stefan Maus
Keyword(s):  
Magnetic Anomaly ◽  
Magnetic Data ◽  
Data Sets ◽  
The World ◽  
Anomaly Map
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