The geological interpretation of gravity and magnetic surveys over the exposed southern margin of the Galway Granite, Ireland

The striking 'fit' of aeromagnetic and gravity data from the Precambrian of northwest Saskatchewan, combined with known and nearby analogous, geological relationships, suggests the presence of a northeast-trending belt, 250 × 20 miles (400 × 30 km), of early Proterozoic (?) metasedimentary rocks, probably magnetite-bearing meta-arkoses. This structural–sedimentary unit might have economic possibilities analogous to other northeast-striking, Precambrian, lower Proterozoic (?), metasedimentary belts of northern Saskatchewan, the Virgin River Belt, and the Wollaston Trend.

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COMPLEX GEOPHYSICAL STUDIES OF THE IVANO-FRANKIVSK NATIONAL TECHNICAL UNIVERSITY OF OIL AND GAS TERRITORY

Oil and Gas Power Engineering ◽

10.31471/1993-9868-2019-1(31)-7-17 ◽

2019 ◽

pp. 7-17

Author(s):

M. V. Shtogryn ◽

S. G. Anikeyev ◽

O. O. Synytska

Keyword(s):

Oil And Gas ◽

Magnetic Anomalies ◽

Research Area ◽

Geological Interpretation ◽

Gravity And Magnetic ◽

Small Intensity ◽

National University ◽

Electrical Sounding ◽

Electrical Prospecting ◽

Local Anomalies

The results of high-precision integrated geophysical studies of the Ivano-Frankivsk National University territory are presented. Research methods used are electrical prospecting and gravity and magnetic prospecting. According to the results of geodetic measurements and field geophysical observations, heights maps of the territory, regional components and detailed maps of local anomalies of the gravitational and magnetic fields, and also, according to the data of vertical electrical sounding, geoelectric sections along interpretation profiles were constructed. For the construction data on the geological and tectonic structure of the section to the depths of the first hundred meters were used, as well as geophysical materials obtained in previous years through of the Ivano-Frankivsk city territory. The analysis of the general behavior of the regional components of the gravimagnetic fields and morphology of geophysical anomalies was performed. The geological interpretation of the identified individual local gravitational and magnetic anomalies is presented. A regional field of gravity tends to increase in the direction of increasing heights in the study area and the regional magnetic field has an insignificant, but inverse relationship. A series of positive small intensity local anomalies of the field of gravity is probably due to the rocks of the Kosovska and Tyraska suite, for example, compacted carbonates or anhydrites. Local magnetic anomalies have a relatively small intensity ranging from -100 nTl to 500 nTl and due mainly to university facilities and communications. According to the results of the analysis of the intensity of geophysical fields, a general forecast estimate of the ecological state of the research area is presented. The obtained field intensity values are much lower than the sanitary norms.

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Geological interpretation of the northern flank of the Matagami camp, Quebec, using gravity and magnetic inversions

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2018-0049 ◽

2019 ◽

Vol 56 (5) ◽

pp. 471-482 ◽

Cited By ~ 1

Author(s):

Thibaut Astic ◽

Michel Chouteau

Keyword(s):

Gravity Data ◽

Volcanic Rocks ◽

Three Dimensional ◽

Gravity Models ◽

Earth Model ◽

Surface Geometry ◽

Northern Flank ◽

Geological Interpretation ◽

Geophysical Model ◽

Gravity And Magnetic

The northern flank of the Galine anticline of the Matagami camp has been well known for decades for hosting polymetallic VMS deposits (mostly copper and zinc). In such an already explored area, sophisticated exploration tools must be used in the hope of generating new information. By integrating geophysical, petrophysical, and geological data into a three-dimensional (3D) common earth model to constrain gravity and magnetic inversions, our objective was to validate and improve the geological interpretations of the area and to highlight geophysical anomalies unexplained in the current geological model. Both 3D magnetic and gravity data inversions confirm the surface geometry and the steep dip of the geological units. The inverted gravity models indicate that units observable at the surface of the northern flank extend subvertically to several kilometres in depth. The pyroxenitic phase of the Bell River Complex is most certainly dipping steeply to the south, contrary to some surface measurements. The Olga pluton shows no significant decrease in width at depth, with the exception of the west end, which appears to be an apophysis. A major unknown mass, which may correspond to a synvolcanic mafic intrusion that is not outcropping, is revealed in the Allard River volcanic rocks. This improved geophysical model featuring geometrical constraints obtained by careful processing and inversion of the potential-fields data could contribute to new exploration targets.

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Martin Harold Phillips Bott. 12 July 1926—20 October 2018

Biographical Memoirs of Fellows of the Royal Society ◽

10.1098/rsbm.2019.0009 ◽

2019 ◽

Vol 67 ◽

pp. 89-117

Author(s):

Anthony Brian Watts

Keyword(s):

Oil And Gas ◽

Deep Structure ◽

Oil And Gas Industry ◽

Magnetic Anomalies ◽

Earth’S Crust ◽

Field Methods ◽

Crust And Upper Mantle ◽

Geological Interpretation ◽

Gravity And Magnetic ◽

Earth's Crust

Martin Bott was a geophysicist who made fundamental contributions to our understanding of gravity and magnetic anomalies and their geological interpretation. His research on the deep structure of the Earth's crust was both pioneering and innovative, and he showed how field geophysical measurements could be used to address geological problems such as the mechanics of granite emplacement, sedimentary basin formation and mountain building. When he began his research, the use of gravity and magnetic anomalies to understand deep crustal structure was in its infancy and largely confined to research laboratories in the oil and gas industry. Four decades later his lifetime efforts have seen the emergence of potential field methods as one of the principal means of constraining the structure, stress state and long-term strength of the Earth's crust and upper mantle in continents and oceans. Martin was an inspiring undergraduate teacher and outstanding supervisor, as reflected by his many research students who went on to prominent leadership positions in academia, government and industry. He leaves a legacy of more than 150 scientific papers in peer-reviewed journals and a lucidly written and beautifully illustrated textbook. As well as his many scientific achievements, Martin was an accomplished mountaineer, a dedicated churchgoer and an avid gardener. He saw no conflict between his science and his enduring Christian faith.

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New Perspective in Regional and Residual Separation of Gravity and Magnetic Data Processing

RSF Conference Series: Engineering and Technology ◽

10.31098/cset.v1i1.400 ◽

2021 ◽

Vol 1 (1) ◽

pp. 204-210

Author(s):

Wiji Raharjo ◽

Indiati Retno Palupi ◽

Oktavia Dewi Alfiani

Keyword(s):

Data Processing ◽

Original Data ◽

Magnetic Data ◽

Geological Interpretation ◽

Interactive Tools ◽

Gravity And Magnetic ◽

Anomaly Map ◽

New Perspective ◽

Gravity And Magnetic Data ◽

2D Fft

Separation between Regional and Residual anomaly in Gravity and Magnetic data processing is very important to get the best result in geological interpretation. Several method were used to solve this problem like upward continuation and polynomial fitting. With the same principle, 2D FFT is applied by make an interactive tools based on Matlab Language Programming, named “Oasis Ala-Ala”. It adopt the algorithm from software Oasis. It started with make visualization map or the original data, then the map divide into some grids. Each of grid contain gravity or magnetic data. Then it transformed from special to wavenumber domain. After that, it convolve with our own filter matrix. And the last step is inverse it to get the regional and residual anomaly map. However, Matlab is powerful in facilitate this process in the GUI Toolbox. One important thing is the size of gravity and magnetic data. It will improve to Filter matrix size before do inverse process.

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