CRUSTAL MAGNETIC ANOMALIES AND GEOLOGICAL STRUCTURE IN THE YUNNAN REGION

2017 ◽  
Vol 60 (6) ◽  
pp. 613-626
Author(s):  
WEN Li-Min ◽  
KANG Guo-Fa ◽  
BAI Chun-Hua ◽  
GAO Guo-Ming ◽  
ZHENG An-Ran ◽  
...  
Keyword(s):  
Magnetic Anomalies ◽  
Geological Structure ◽  
Yunnan Region

Ground magnetic survey for the investigation of magnetic minerals at Iboro Village, Abeokuta, south-western Nigeria

2021 ◽  
Vol 20 (2) ◽  
pp. 99-106
Author(s):  
O.I. Popoola ◽  
O.A. Adenuga ◽  
E.O. Joshua
Keyword(s):  
Magnetic Anomalies ◽  
Geological Structure ◽  
Magnetic Survey ◽  
Magnetic Minerals ◽  
Contour Maps ◽  
Ogun State ◽  
Geological Map ◽  
Regional Gradient ◽  
Ground Magnetic ◽  
Iron Ore Deposit

The geological map of the old western region of Nigeria indicates the presence of iron ore deposit at Iboro village Ogun state (7.9983o - 7.99933o N, 3.5790o - 3.5890o E). Hence a ground magnetic survey was carried out at a location at Iboro village so as to delineate the subsurface magnetic anomalies and to know whether the anomalies favour accumulation of magnetic minerals. The survey was carried out using high resolution proton precession magnetometer model G-856X. Eight traverses were run at 5m separations and earth magnetic intensity values were measured at 10m intervals along each traverse; the acquired data were corrected for drift. The residual anomalies obtained by removal of regional gradient from observed data using trend analysis were presented as profiles and maps. The treated data were qualitatively and quantitatively interpreted and the results gave values for the total ground magnetic anomalies that varied between a minimum and maximum peak values of about -33.0 and 30.6nT respectively. Depth to the basement rock was estimated using Peter’s half slope method which gave a maximum depth of about 13m. The contour maps and the total relative graphs present the subsurface picture of the geological structure that is assumed to harbour the metallic minerals through the action of the field towards the concentration of anomalies. It was suspected that the overburden was relatively thin in the study area and the minerals were at a shallow depth.

A STATISTICAL ANALYSIS OF SOME AEROMAGNETIC MAPS FROM THE NORTHWESTERN CANADIAN SHIELD

Geophysics ◽  
1964 ◽  
Vol 29 (4) ◽  
pp. 582-601 ◽  
Author(s):  
C. W. Horton ◽  
W. B. Hempkins ◽  
A. A. J. Hoffman
Keyword(s):  
Statistical Analysis ◽  
Structural Information ◽  
Wave Length ◽  
Magnetic Anomalies ◽  
Geological Structure ◽  
Spectral Techniques ◽  
Structural Trend ◽  
Power Spectral ◽  
Good Agreement ◽  
Geologic Data

Autocovariance and power‐spectral techniques are applied to aeromagnetic maps from the District of MacKenzie, Northwest Territories, Canada, to obtain trend directions and other structural information. Such trends are representative of the geologic structures creating the magnetic anomalies, and they are subjected to structural analysis. Results of computations for four maps 17×17 miles in size and one profile 185 miles long show good agreement with the known geological structure of the region. These analyses predict a dominant structural trend from S 18° W to N 18° E and two associated conjugate shear directions. In addition, an unexplained basic periodicity with a wave length of 15 miles is shown. This type of statistical analysis is suggested as a new tool for the extension of geologic data into inaccessible or covered regions.

APPLICATION OF THE MAGNETIC ANOMALIES IN IDENTIFICATION THE STRUCTURE OF THE CRYSTALLINE BASEMENT OF THE SOUTH–EASTERN POLAND

2017 ◽  
pp. 17-48
Author(s):  
Teresa GRABOWSKA ◽  
Grzegorz BOJDYS ◽  
Zdzislaw PETECKI
Keyword(s):  
Magnetic Properties ◽  
Western Europe ◽  
Three Dimensional ◽  
Gravity Anomalies ◽  
Magnetic Anomalies ◽  
Geological Structure ◽  
Crystalline Basement ◽  
East European Craton ◽  
East European ◽  
South Eastern

South-eastern Poland is situated between the East European Craton (EEC), the Paleozoic and Mezosoic of Western Europe and the Carpathians. Complex geological structure of the area is reflected on the maps of potential fields anomalies. The analyses of the total magnetic intensity anomaly map ∆T and the vertical derivatives of these anomalies in relation to geological data provide many information concerning the structure and magnetic properties of rocks of the crystalline basement. These analyses indirectly reveal the degree of the petrologic diversification and the tectonics of the basement in comparison with the adjoining blocks of the Paleozoic and Variscan orogens and their basement as well as those located in the area of the Trans–European Suture Zone (TESZ). Two dimensional (2D) magnetic models of the basement along the seismic profiles (CEL 01, CEL 05) and corresponding three dimensional (3D) model have been constructed. This interpretation is based on spectral analysis of the magnetic anomalies and their quantitative interpretation which includes data from the CELEBRATION 2000 project, as well as information concerning the magnetic properties of rocks made available through drilling. The comparative analysis of maps showing magnetic and gravity anomalies have revealed the architecture of the crystalline basement in the area where the East European Craton (EEC) is in contact with the Paleozoic and Mezosoic of Western Europe, as well as its impact on the image of residual gravity anomalies within the area of the craton.

scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2011 ◽  
Vol 1(10)2011 (1(10)) ◽  
pp. 127-133 ◽  
Author(s):  
V. H. Kuznietsova ◽  
◽  
V. Yu. Maksymchuk ◽  
Keyword(s):  
Magnetic Field ◽  
East European Platform ◽  
Magnetic Anomalies ◽  
Geological Structure ◽  
East European ◽  
Anomalous Magnetic Field

Peculiarities of anomalous magnetic field in Ukrainian Carpathians territory were considered. It was stated that on the base of magnetic anomalies characters in can be divided in 4 zones that generally matches with main tectonic elements of the region (in SW – NE direction): Transcarpathian trough, Folded Carpathians, Precarpathian trough, SE edge of East-European platform. It was concluded that the peculiarities of geological structure and tectonics of Carpathians are reflected in anomalous magnetic field of the region.

scholarly journals Magnetic field of the Western Carpathians (Slovakia): reflections on the structure of the crust

2010 ◽  
Vol 61 (5) ◽  
pp. 437-447 ◽  
Author(s):  
Peter Kubeš ◽  
Vladimír Bezák ◽  
Ľudovít Kucharič ◽  
Miroslav Filo ◽  
Jozef Vozár ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Anomalies ◽  
Geological Structure ◽  
Variable Magnetic Field ◽  
Present Knowledge ◽  
Western Carpathians ◽  
The West ◽  
Anomalous Field ◽  
Sizable Number

Magnetic field of the Western Carpathians (Slovakia): reflections on the structure of the crustA new digital magnetic map of Slovakia on the scale of 1: 200,000 and 1: 500,000 was compiled at the end of 2008 as the output of database magnetic objects from the whole territory of Slovakia at a scale of 1: 50,000. The variable geological structure of the West Carpathian crust is depicted in the equally variable magnetic field of this region. A sizable number of magnetic anomalies with manifold character have been recognized. The basic anomalies distribution was divided into two groups: anomalies connected with rocks of the pre-Neogene basement and anomalies which originate in Neogene and Quaternary volcanic products. Most of the significant anomalies in the pre-Neogene basement were interpreted, modelled and consequently its geological and tectonic classification was worked out. On the basis of the anomalous field features, the following sources of anomalies have been distinguished: a) known, located on the surface, or at shallow depths verified by boreholes, mainly expressed by simple morphology, b) deep-seated and expressed by complicated morphology, reinterpreted or newly interpreted and also problematic. According to our present knowledge the interpretations are insufficient and remain open for further investigation. The above mentioned sources of magnetic anomalies are classified in terms of tectonic provenience to the main tectonic units.

scholarly journals Distribution of the Crustal Magnetic Field in Sichuan-Yunnan Region, Southwest China

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Chunhua Bai ◽  
Guofa Kang ◽  
Guoming Gao
Keyword(s):  
Magnetic Field ◽  
Magnetic Anomaly ◽  
Geological Structure ◽  
Geophysical Field ◽  
Yunnan Region ◽  
Crustal Magnetic Anomaly ◽  
Red River Fault ◽  
Anomaly Map ◽  
The Relationship ◽  
Active Block

Based on the new and higher degree geomagnetic model NGDC-720-V3, we have investigated the spatial distribution, the altitude decay characteristics of the crustal magnetic anomaly, the contributions from different wavelength bands to the anomaly, and the relationship among the anomaly, the geological structure, and the geophysical field in Sichuan-Yunnan region of China. It is noted that the most outstanding feature in this area is the strong positive magnetic anomaly in Sichuan Basin, a geologically stable block. Contrasting with this feature, a strong negative anomaly can be seen nearby in Longmen Mountain block, an active block. This contradiction implies a possible relationship between the magnetic field and the geological activity. Completely different feature in magnetic field distribution is seen in the central Yunnan block, another active region, where positive and negative anomalies distribute alternatively, showing a complex magnetic anomaly map. Some fault belts, such as the Longmen Mountain fault, Lijiang-Xiaojinhe fault, and the Red River fault, are the transitional zones of strong and weak or negative and positive anomalies. The corresponding relationship between the magnetic anomaly and the geophysical fields was confirmed.

The geological structure of the Emilia-Tuscany Northern Apennines and Alpi Apuane

2019 ◽  
Vol 11 (2.5) ◽  
pp. 1-78 ◽  
Author(s):  
Paolo Conti ◽  
Gianluca Cornamusini ◽  
Luigi Carmignani ◽  
Giancarlo Molli
Keyword(s):  
Geological Structure ◽  
Northern Apennines

FEATURES OF GEOLOGICAL STRUCTURE AND PETROLEUM OIL POTENTIAL OF VICHULOVSKAYA FORMATION WITHIN VOSTOCHNO-KAMENNYI DEPOSIT (WESTERN SIBERIA)

2018 ◽  
pp. 33-39
Author(s):  
R. R. Gabdullin ◽  
O. N. Biryukova ◽  
R. A. Akhmedov
Keyword(s):  
Western Siberia ◽  
Geological Structure ◽  
Test Results ◽  
Geological Information ◽  
Petroleum Oil

The analysis of geological and geophysical materials in order to study the peculiarities of the geological structure of the Vikulov Formation within the Vodorazdel license area was carried out. The presented factual material makes it possible to characterize the geological structure of the investigated area more informatively and for interpreting of seismic materials. The analysis of geological information (GIS and test results) confirms the approved water–oil contact (WOC) level in the investigated section of the deposit, which makes it possible to recalculate its reserves.

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