Quantitative Interpretation of Magnetic Anomalies from Thick Bed, Horizontal Plate and Intermediate Models Under Complex Physical-Geological Environments in Archaeological Prospection

2015 ◽  
Vol 22 (4) ◽  
pp. 255-268 ◽  
Author(s):  
Lev V. Eppelbaum
Keyword(s):  
Magnetic Anomalies ◽  
Quantitative Interpretation ◽  
Horizontal Plate ◽  
Archaeological Prospection

scholarly journals ARCHAEOLOGICAL PROSPECTION IN SOUTHEASTERN PARÁ STATE, BRAZIL USING GEOPHYSICAL METHODS: A CASE STUDY OF SÍTIO DOMINGOS

2013 ◽  
Vol 31 (3) ◽  
pp. 515 ◽  
Author(s):  
José Gouvêa Luiz ◽  
Edithe Da Silva Pereira
Keyword(s):  
Ground Penetrating Radar ◽  
Geophysical Methods ◽  
Main Tool ◽  
Archaeological Site ◽  
Magnetic Anomalies ◽  
Archaeological Excavation ◽  
Archaeological Prospection ◽  
Magnetic Resistivity ◽  
Ground Penetrating

ABSTRACT. Magnetic, resistivity and ground-penetrating radar (GPR) methods were applied to Sítio Domingos, a Brazilian archaeological site located in Pará State, to find objects buried by an ancient civilization that may have inhabited the site. Archaeological excavations based on the locations of magnetic anomalies reveal a concentration of ceramic fragments and pots. The correlation between the resistivity models and the soil profile of the study area suggests that the resistivity range of 2000 to 2500 ohm-m represents the archaeological occupation layer. Several anomalous features detected by GPR are correlated with magnetic anomalies. However, when these features are analyzed independently of the magnetic anomalies, they do not conclusively represent the objects being searched. Therefore, GPR is not recommended as the main tool for archaeological prospection in the study area.Keywords: magnetometry, electrical resistivity, GPR, archaeological excavation. RESUMO. Os métodos magnético, resistividade e radar de penetração no solo (GPR) foram aplicados no Sítio Domingos, um sítio arqueológico brasileiro localizado no Estado do Pará, para encontrar objetos enterrados por uma civilização antiga que pode ter habitado a região. Escavações arqueológicas com base nos locais de anomalias magnéticas revelaram uma concentração de fragmentos de cerâmica e vasos. A correlação entre os modelos de resistividade e do perfil do solo da área de estudo sugere que a faixa de resistividade de 2000-2500 ohm-m representa a camada de ocupação arqueológica. V´arias feições anômalas detectadas pelo GPR são correlacionáveis com anomalias magnéticas. No entanto, quando essas feições são analisadas independente das anomalias magnéticas, elas não representam de forma conclusiva os objetos que est~so sendo procurados. Portanto, o GPR não é recomendado como a principal ferramenta de prospecção arqueológica na área de estudo.Palavras-chave: magnetometria, resistividade elétrica, GPR, escavação arqueológica.

scholarly journals Analisis Sebaran Mineral Logam Pada Sedimentasi Batuan Di Daerah Kertajadi, Cidaun, Kabupaten Cianjur, Jawa Barat Menggunakan Metoda Geomagnet

Wahana Fisika ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 37
Author(s):  
Rajab Basuki ◽  
Nanang Dwi Ardi ◽  
Mimin Iryanti
Keyword(s):  
Magnetic Anomaly ◽  
Mineral Exploration ◽  
Ferrous Metal ◽  
Magnetic Anomalies ◽  
Coastal Areas ◽  
Inversion Method ◽  
Quantitative Interpretation ◽  
West Java ◽  
Value Range ◽  
The Difference

Cidaun merupakan salah satu daerah pesisir pantai selatan yang terletak pada Kabupaten Cinajur Provinsi Jawa Barat. Salah satu kelebihan dari daerah pesisir pantai selatan Pulau Jawa adalah terdapat banyaknya mineral logam penghasil besi yang tersebar luas di sepanjang pesisir pantai. Oleh karena itu dilakukanlah eksplorasi untuk memetakan sebaran mineral logam yang ada di daerah Cidaun. Dalam melakukan eksplorasi mineral logam dibutuhkan suatu metode yang paling efektif yaitu eksplorasi geofisika dengan menggunakan metode geomagnet. Proses pengolahan data pada metode geomagnet dilakukan dengan menghitung nilai anomali magnetik dari medan magnetik total yang telah dilakukan koreksi terhadap koreksi harian dan koreksi IGRF. Kemudian dengan metode inversi data yang telah didapat dijadikan sebuah model. Selain itu dilakukan juga interpretasi kualitatif dan interpretasi kuantitatif. Interperetasi kualitatif dilakukan pada data yang telah dimodelkan menggunakan software surfer 11, apabila data tersebut terdapat anomali magnetik bernilai sangat tinggi yang berdekatan dengan nilai anomali magnetik bernilai rendah atau perubahan nilai anomali terjadi secara signifikan kemudian dilakukan proses interpretasi secara kuantitatif. Interpretasi kuantitatif pada penelitian ini dengan dilakukan deliniasi berupa proses sayatan pada perbedaan nilai anomali magnetik yang terjadi perubahan secara signifikan. Tahap selanjutnya data dari proses sayatan tersebut kemudian dilakukanlah pemodelan menggunakan software mag2dc untuk mengetahui sebaran mineral logam dapa daerah tersebut. Berdasarkan data yang telah diolah pada daerah Kertajadi, Cidaun, Kabupaten Cianjur, Jawa Barat dengan koordinat 698283 easting - 757162 easting dan 9180169 northing - 9171050 northing memiliki rentang nilai anomali magnetik -5 nT – 145 nT. Sedangkan nilai anomali magnetik pada daerah yang telah dilakukan proses sayatan memiliki rentang nilai 84.18 nT - 119.69 nT dengan nilai susptibilitas -0.041000 – 0.050001. Dari rentang nilai suseptibilitas tersebut diduga sebaran mineral yang yang memiliki nilai suseptibilitas positif merupakan bijih besi sedangkan yang bernilai negatif merupakan lempung dan endapan pasir. Dari hasil dari penelitian ini diharapkan data tersebut dapat dijadikan informasi dan referensi bagi masyarakat, peneliti lain dan pengusaha tambang dalam eksplorasi mineral logam.Cidaun is one of the coastal areas of the southern coast located in the district of West Java province Cinajur. One of the advantages of the southern coastal areas of Java is that there are many ferrous metal mineral producer widespread along the coast. Therefore, the exploration was undertaken to map the distribution of metallic minerals in the area Cidaun. In conducting metal mineral exploration required a most effective method is a geophysical exploration using geomagnetic methods. Data processing on geomagnetic method is done by calculating the value of the magnetic anomalies of the total magnetic field has a daily correction of correction and correction IGRF. Then, with the inversion method of data has been obtained serve as a model. The researcher also interpretation of qualitative and quantitative interpretation. Qualitative Interperetasi performed on the data that has been modeled using software surfer 11, when the inputs are very high-value magnetic anomalies adjacent to the value of the magnetic anomalies of low value or change in value of the anomaly occurred significantly later performed quantitative interpretation process. Quantitative interpretation in this study conducted a process of delineation of the incision on the difference in magnetic anomaly change significantly. The next stage of the data are then perform the incision process modeling using software mag2dc to determine the distribution of metallic minerals onshore areas. Based on the data that has been processed in the region Kertajadi, Cidaun, Cianjur, West Java coordinate 698283 easting - 757162 easting and 9180169 northing - 917105 northing and has a value range of magnetic anomaly -5 nT - 145 nT. While the value of magnetic anomalies in the area that has been carried out the process of incisions have a range of values 84.18 nT - 119.69 nT with susptibilitas value -0.041000 - 0.050001. Of the value range susceptibility is suspected distribution of minerals that have a positive susceptibility value is the iron ore which is negative while the clay and sand deposits. From the results of this study are expected data can be made of information and reference for the community, other researchers and mining company in mineral exploration.

scholarly journals Pemodelan 2D Batuan Bawah Permukaan Daerah Mamuju Sulawesi Barat Dengan Menggunakan Metode Magnetik

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Muhammad Irsyad ◽  
Sutrisno Sutrisno ◽  
Dwi Haryanto
Keyword(s):  
Magnetic Anomaly ◽  
Magnetic Anomalies ◽  
Magnetic Method ◽  
Government Agencies ◽  
Quantitative Interpretation ◽  
Magnetic Intensity ◽  
Contour Map ◽  
A Value ◽  
Qualitative Interpretation ◽  
The Earth

Abstrak. Batuan merupakan benda yang berasal dari magma yang mendingin di dalam bumi. Untuk mengetahui kondisi batuan perlu di lakukan penelitian. Mamuju merupakan daerah yang sedang hangat dalam perbincangan peneliti tentang bagaimana kandungan di bawah permukaan daerah Mamuju, Sulawesi Barat. Daerah ini juga merupakan daerah yang diteliti oleh instansi-instansi pemerintah termasuk PTBGN-BATAN. Penelitian ini bertujuan untuk melakukan pemodelan bawah permukaan bumi. Tujuannya untuk memberikan informasi tentang kondisi baik itu bentuk maupun kedalaman batuan. penelitian ini menggunakan metode magnetik dan metode ini merupakan metode yang tepat untuk membuat model bawah permukaan bumi. Hasil interpretasi kualitatif diperoleh peta kontur intensitas magnetik total dan anomali magnetik. Peta kontur intensitas magnetik total memiliki nilai sebesar 41286,5 – 42280 nT. Sedangkan anomali magnetik memiliki nilai -760,1 – 231,8 nT. Daerah A dan daerah B merupakan daerah yang memiliki anomali tinggi. Hasil interpretasi kuantitatif didapat ada 4 model bawah permukaan yang masing-masing terdapat batuan yang sama yaitu batuan breksi dengan nilai suseptibilitas 0,0006 – 0,00075 satuan cgs dan batuan lava dengan nilai suseptibilitas 0.001 – 0.0015 satuan cgs. daerah yang dilakukan pemodelan fokus pada daerah Hulu Mamuju, hal ini disebabkan karena menurut peta kontur daerah tersebut merupakan daerah yang memiliki anomali magnetik yang tinggi.   Abstract. The rocks are objects derived from the magma cooled in the earth. To determine the condition of the rock is necessary to do research. Mamuju is an area that is warm in conversation investigators about how the content of subsurface area Mamuju, West Sulawesi. This area is also the area investigated by government agencies including PTBGN-BATAN. This study aimed to modeling subsurface. The goal is to provide information about the condition of both the shape and depth of rock. This study uses a magnetic method and this method is an appropriate method to create a model of the earth's subsurface. Qualitative interpretation of results obtained contour map of total magnetic intensity and magnetic anomalies. The total magnetic intensity contour map has a value of 41286.5 to 42280 nT. While the magnetic anomaly has a value of -760.1 - 231.8 nT. Area A and area B is an area that has a high anomaly. Results obtained quantitative interpretation there are 4 models of the subsurface that each contained the same rock is rock breccia with values susceptibility of 0.0006 to 0.00075 cgs units and lava rock with susceptibility value 0.001 - 0.0015 cgs unit. modeling area focuses on upstream area Mamuju, this is because according to the contour map of the area is an area that has a high magnetic anomaly.

Regional magnetic anomalies, magnetic units, and crustal structure in the Kenora District of Ontario

1968 ◽  
Vol 5 (5) ◽  
pp. 1277-1296 ◽  
Author(s):  
Donald H. Hall
Keyword(s):  
Magnetic Susceptibility ◽  
Crustal Structure ◽  
Continuous Distribution ◽  
Magnetic Anomalies ◽  
Canadian Shield ◽  
Superior Province ◽  
Quantitative Interpretation ◽  
Variable Intensity ◽  
Depth Determination ◽  
Greenstone Belts

Regional magnetic anomalies were smoothed from aeromagnetic maps in a part of the Superior Province of the Canadian Shield (latitudes 48°45′ to 50°00′ N; longitudes 93°30′ to 95°00′ W). It was found that anomaly lows lie over Keewatin greenstone belts, and highs over adjacent granitic areas.Surface mapping of magnetic susceptibility and NRM was combined with quantitative interpretation of the regional magnetic anomalies. It was found that, when considered regionally, magnetization lies primarily in the granitic bodies, with a continuous distribution from the surface down to the Intermediate (Conrad) discontinuity. Intensity of magnetization increases with depth, and is directed nearly along the direction of the present-day geomagnetic field.As an aid to the interpretation, a method of depth determination for deep crustal magnetic units with sloping sides is introduced, and one for variable intensity of magnetization with depth.

QUANTITATIVE INTERPRETATION OF VERTICAL MAGNETIC ANOMALIES OVER VEINS

Geophysics ◽  
1950 ◽  
Vol 15 (4) ◽  
pp. 667-686 ◽  
Author(s):  
Kenneth L. Cook
Keyword(s):  
Magnetic Field ◽  
Magnetic Anomaly ◽  
Magnetic Induction ◽  
Vertical Component ◽  
Magnetic Anomalies ◽  
Quantitative Interpretation ◽  
Magnetic Intensity ◽  
Magnetic Inclination ◽  
Magnetic North ◽  
The Magnetic Field

By using ordinary magnetic induction methods of analysis, Haalck, Heiland, and others have developed formulas which express the magnetic anomaly over a vertical or inclined vein of tabular shape as a function of the susceptibility, dimensions, shape, and disposition of the vein, and of the strength and direction of the earth’s magnetic field. On the basis of these fundamental formulas, other formulas for the vertical component of the magnetic field are derived in the present paper for such veins in intermediate northern magnetic latitudes. Special emphasis is given to the orientation of the veins relative to the magnetic north direction. Several families of vertical magnetic intensity curves for veins with different strikes and dips are given. All theoretical curves for veins striking magnetic north are plotted in terms of a parametric unit so that, once plotted, they can be used repeatedly in different districts, provided a proper multiplying factor is chosen for the observed curve. The importance of the transverse horizontal magnetization effect under certain conditions of orientation is demonstrated. It is shown mathematically that small vertical magnetic anomalies are to be expected for thin veins striking east and dipping south at an angle equal to, or approximately equal to, the complement of the angle of magnetic inclination.

QUANTITATIVE INTERPRETATION OF MAGNETIC AND GRAVITATIONAL ANOMALIES

Geophysics ◽  
1944 ◽  
Vol 9 (4) ◽  
pp. 463-493 ◽  
Author(s):  
Ervand G. Kogbetliantz
Keyword(s):  
Magnetization Vector ◽  
Magnetic Anomalies ◽  
Density Contrast ◽  
Quantitative Interpretation ◽  
New Interpretation ◽  
Interpretation Method ◽  
Magnetic Case ◽  
Gravitational Anomalies

A new interpretation method for gravitational and magnetic anomalies based on the use of average values (integrals) of suitably chosen functions of the observed quantity is discussed and illustrated by application to the particular case of a symmetric anticline. The quantitative interpretation yields the position of the apex, the slope of the sides, the thickness, the depth of the base of the anticline, as well as the density contrast for the gravitational case and the magnitude and direction of the magnetization vector for the magnetic case.

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