QUARTZ PROSPECTING WITH INDUCED POLARIZATION (IP) AND RESISTIVITY BY USING GRADIENT AND DIPOLE-DIPOLE ARRAYS

2015 ◽  
Vol 33 (4) ◽  
Author(s):  
José Domingos Faraco Gallas
Keyword(s):  
Induced Polarization ◽  
Granitic Rocks ◽  
Economic Interest ◽  
High Quality ◽  
Geophysical Surveys ◽  
Geophysical Anomalies

ABSTRACT. Geophysical surveys were accomplished in Bahia, Brazil, and they aimed at detecting resistivity and/or IP geophysical anomalies that may be correlated to large quartz mass occurrences that, in some cases, may have economic interest (hyaline high-quality quartz or quartz with rutile inclusions). These quartz masses occur in granitic rocks. The indirect geophysical detection of quartz masses was possible, however it could not differentiate the aforementioned types of quartz. After digging wells and trenches, the presence of milky quartz masses, without economic interest, was confirmed.Keywords: resistivity, IP, quartz prospecting. RESUMO. Os levantamentos geofísicos foram efetuados no interior da Bahia, Brasil, e tiveram como objetivo a detecção de anomalias geofísicas de resistividade e/ou IP que pudessem ser correlacionáveis às ocorrências de grandes massas quartzosas que, em alguns casos, podem conter quartzo de interesse econômico – quartzo hialino de boa qualidade ou com inclusões de rutilo. Estas massas quartzosas estão contidas em rochas de composição granítica. A detecção de massas quartzosas por meios geofísicos indiretos foi possível, contudo não permitiu diferenciar os tipos de quartzo supracitados. Conforme confirmações posteriores com escavação de poços e trincheiras, os resultados detectaram a presença das massas quartzosas, porém de quartzo leitoso, sem interesse econômico.Palavras-chave: resistividade, IP, prospecção de quartzo.

scholarly journals QUARTZ PROSPECTING WITH INDUCED POLARIZATION (IP) AND RESISTIVITY BY USING GRADIENT AND DIPOLE-DIPOLE ARRAYS

2015 ◽  
Vol 33 (4) ◽  
pp. 555
Author(s):  
José Domingos Faraco Gallas
Keyword(s):  
Induced Polarization ◽  
Granitic Rocks ◽  
Economic Interest ◽  
High Quality ◽  
Geophysical Surveys ◽  
Geophysical Anomalies

ABSTRACT. Geophysical surveys were accomplished in Bahia, Brazil, and they aimed at detecting resistivity and/or IP geophysical anomalies that may be correlated to large quartz mass occurrences that, in some cases, may have economic interest (hyaline high-quality quartz or quartz with rutile inclusions). These quartz masses occur in granitic rocks. The indirect geophysical detection of quartz masses was possible, however it could not differentiate the aforementioned types of quartz. After digging wells and trenches, the presence of milky quartz masses, without economic interest, was confirmed.Keywords: resistivity, IP, quartz prospecting. RESUMO. Os levantamentos geofísicos foram efetuados no interior da Bahia, Brasil, e tiveram como objetivo a detecção de anomalias geofísicas de resistividade e/ou IP que pudessem ser correlacionáveis às ocorrências de grandes massas quartzosas que, em alguns casos, podem conter quartzo de interesse econômico – quartzo hialino de boa qualidade ou com inclusões de rutilo. Estas massas quartzosas estão contidas em rochas de composição granítica. A detecção de massas quartzosas por meios geofísicos indiretos foi possível, contudo não permitiu diferenciar os tipos de quartzo supracitados. Conforme confirmações posteriores com escavação de poços e trincheiras, os resultados detectaram a presença das massas quartzosas, porém de quartzo leitoso, sem interesse econômico.Palavras-chave: resistividade, IP, prospecção de quartzo.

Aeromagnetic survey in central West Greenland: project Aeromag 2001

2002 ◽  
pp. 67-72 ◽  
Author(s):  
Thorkild M. Rasmussen
Keyword(s):  
High Resolution ◽  
Magnetic Measurements ◽  
Geophysical Data ◽  
High Quality ◽  
Aeromagnetic Survey ◽  
Original Series ◽  
West Greenland ◽  
Airborne Measurements ◽  
Geophysical Surveys ◽  
Airborne Geophysical Data

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article. Rasmussen, T. M. (1). Aeromagnetic survey in central West Greenland: project Aeromag 2001. Geology of Greenland Survey Bulletin, 191, 67-72. https://doi.org/10.34194/ggub.v191.5130 The series of government-funded geophysical surveys in Greenland was continued during the spring and summer of 2001 with a regional aeromagnetic survey north of Uummannaq, project Aeromag 2001 (Fig. 1). The survey added about 70 000 line kilometres of high-quality magnetic measurements to the existing database of modern airborne geophysical data from Greenland. This database includes both regional high-resolution aeromagnetic surveys and detailed surveys with combined electromagnetic and magnetic airborne measurements.

A hybrid correlation denoising method based on complex resistivity and application on spread spectrum induced polarization data

Geophysics ◽  
2021 ◽  
pp. 1-35
Author(s):  
Siming He ◽  
Jian Guan ◽  
Yi Wang ◽  
Xiu Ji ◽  
Hui Wang
Keyword(s):  
Hybrid Method ◽  
Spread Spectrum ◽  
Field Experiments ◽  
Noise Suppression ◽  
Random Noise ◽  
Induced Polarization ◽  
Data Simulation ◽  
Denoising Method ◽  
Complex Resistivity ◽  
Geophysical Surveys

In electrical exploration techniques, an effective suppression method for Gaussian and impulsive random noise in spread spectrum induced polarization (SSIP) continues to be challenging for conventional denoising methods. Remnant noise influences the complex resistivity spectrum and damages the subsequent interpretation of geophysical surveys. We present a hybrid method based on a correlation function and complex resistivity, which introduces the correlation analyses between the transmitting source, the measured potential, and the injected current signal. According to the analyses, reliable results for complex resistivity spectra can be calculated, which can be further used for noise suppression. We apply the hybrid method to both numerical and field experiments to process measured SSIP data. Simulation tests show that the hybrid method not only suppresses the two types of noise but also improves the relative error of the complex resistivity spectrum. Field data processing shows that the hybrid method can minimize the standard deviation of the data and possess a greater ability to distinguish adjacent objects, which can improve the reliability of the data in subsequent processing and interpretation.

scholarly journals Data for the potential gold mineralization mapping with the applications of Electrical Resistivity Imaging and Induced Polarization geophysical surveys

Data in Brief ◽  
2019 ◽  
Vol 22 ◽  
pp. 830-835 ◽  
Author(s):  
Mohd Hariri Arifin ◽  
John Stephen Kayode ◽  
Muhammad Khairel Izwan ◽  
Hussein Ahmed Hasan Zaid ◽  
Hamzah Hussin
Keyword(s):  
Electrical Resistivity ◽  
Gold Mineralization ◽  
Induced Polarization ◽  
Electrical Resistivity Imaging ◽  
Resistivity Imaging ◽  
Geophysical Surveys

Surveying Batavia’s Graveyard: Geophysical controlled experiments and subsurface imaging of archaeological sites on an Indian Ocean coral island

Geophysics ◽  
2017 ◽  
Vol 82 (4) ◽  
pp. B147-B163 ◽  
Author(s):  
Jeffrey Shragge ◽  
David Lumley ◽  
Nader Issa ◽  
Tom Hoskin ◽  
Alistair Paterson ◽  
...  
Keyword(s):  
Sea Water ◽  
Controlled Experiments ◽  
Near Surface ◽  
Survey Techniques ◽  
Geophysical Surveys ◽  
Archaeological Materials ◽  
Coral Island ◽  
Water Saturated ◽  
Ground Penetrating ◽  
Geophysical Anomalies

We conducted geophysical surveys on Beacon Island in the Houtman Abrolhos archipelago offshore Western Australia, to investigate areas of archaeological interest related to the 1629 Batavia shipwreck, mutiny, and massacre. We used three complementary near-surface geophysical survey techniques (total magnetic intensity, electromagnetic induction mapping, and ground-penetrating radar) to identify anomalous target zones for archaeological excavation. Interpreting near-surface geophysical anomalies is often complex and nonunique, although it can be significantly improved by achieving a better understanding of site-specific factors including background conditions, natural variability, detectability limits, and the geophysical response to, and spatial resolution of, buried targets. These factors were not well-understood for Beacon Island nor indeed for the Australian coastal environment. We have evaluated the results of controlled experiments in which we bury known targets at representative depths and analyze the geophysical responses in terms of an ability to detect and resolve targets from natural background variability. The maximum depth of detectability of calibration targets on Beacon Island is limited to approximately 0.5 m due to significant variations in background physical properties between a thin ([Formula: see text]) and highly unconsolidated dry sand, shell, and coral layer of variable thickness overlying a sea-water-saturated sandy half-space. Our controlled measurements have implications for calibrating and quantifying the interpretation of geophysical anomalies in areas of archaeological interest, particularly in coastal and sandy-coral island environments. Our geophysical analyzes contributed to the discovery of archaeological materials and five historical burials associated with the 1629 Batavia shipwreck.

Geodynamic evolution of the Canadian Cordillera — progress and problems

1979 ◽  
Vol 16 (3) ◽  
pp. 770-791 ◽  
Author(s):  
J. W. H. Monger ◽  
R. A. Price
Keyword(s):  
Continental Margin ◽  
Middle Jurassic ◽  
Rocky Mountain ◽  
Ocean Basin ◽  
Strike Slip ◽  
Granitic Rocks ◽  
Canadian Cordillera ◽  
Thrust Faulting ◽  
Western Cordillera ◽  
Geophysical Surveys

The present geodynamic pattern of the Canadian Cordillera, the main features of which were probably established in Miocene time, involves a combination of right-hand strike-slip movements on transform faults along the continental margin, and, in the south and extreme north, convergence in subduction zones in which oceanic lithosphere moves beneath the continent, with consequent magmatism along the continental margin. In the southern Canadian Cordillera, geophysical surveys have outlined the subducting slab and the asthenospheric bulge that occurs beneath and behind the magmatic arc. They also show that there is now no root of thickened Precambrian continental crust beneath the tectonically shortened supracrustal strata in the southern parts of the Omineca Crystalline Belt and Rocky Mountain Belt.The Rocky Mountain, Omineca Crystalline, Intermontane, Coast Plutonic, and Insular Belts, the structural and physiographic provinces that dominate the present configuration of the Canadian Cordillera, were established with the initial uplift and the intrusion of granitic rocks in the Omineca Crystalline Belt in Middle and Late Jurassic time and in the Coast Plutonic Complex in Early Cretaceous time, and they dominated patterns of uplift, erosion and deposition through Cretaceous and Paleogene time. Their development may be due to compression with thrust faulting in the eastern Cordillera, and to magmatism that accompanied subduction and to accretion of an exotic terrane, Wrangellia, in the western Cordillera. Major right-lateral strike-slip faulting, which occurred well east of but sub-parallel with the continental margin during Late Cretaceous and Paleogene time, accompanied major tectonic shortening due to thrusting and folding in the Rocky Mountain Belt as well as the main subduction-related (?) magmatism in the Coast Plutonic Complex.The configuration of the western Cordillera prior to late Middle Jurassic time is enigmatic. Late Paleozoic and early Mesozoic volcanogenic strata form a complex collage of volcanic arcs and subduction complexes that was assembled mainly in the Mesozoic. The change in locus of deposition between Upper Triassic and Lower to Middle Jurassic volcanogenic assemblages, and the thrust faulting in the northern Cordillera may record emplacement of another exotic terrane, the Stikine block, in latest Triassic to Middle Jurassic time.The earliest stage in the evolution of the Cordilleran fold belt involved the protracted (1500 to 380 Ma) development of a northeasterly tapering sedimentary wedge that discordantly overlaps Precambrian structures of the cratonic basement. This miogeoclinal wedge may be a continental margin terrace wedge that was prograded into an ocean basin, but it has features that may be more indicative of progradation into a marginal basin in which there was intermittent volcanic activity, than into a stable expanding ocean basin of the Atlantic type.

African Lakes Reviewed: Creation and Destruction of Biodiversity

1994 ◽  
Vol 21 (3) ◽  
pp. 199-213 ◽  
Author(s):  
E. Barton Worthington ◽  
Rosemary Lowe-McConnell
Keyword(s):  
Human Activities ◽  
Lake Victoria ◽  
Animal Protein ◽  
Economic Interest ◽  
High Quality ◽  
Protein Food ◽  
African Lakes ◽  
Aquatic Fauna

The lakes of Africa provide outstanding examples of biodiversity. Some hundreds of species of aquatic fauna, especially fishes, have been created through evolution taking place in environments which became isolated from each other. The lakes also provide an outstanding example of the loss of biodiversity: in Lake Victoria at least 200 species of fish have almost certainly become extinct through human activities. These lakes have, since Mankind's origin in Africa, provided high-quality animal protein food and with improved management they could provide much more, which adds greatly to their scientific and economic interest.

GEOPHYSICAL SURVEY OF THE ARKANSAS BAUXITE REGION

Geophysics ◽  
1944 ◽  
Vol 9 (3) ◽  
pp. 324-366 ◽  
Author(s):  
Mark C. Malamphy ◽  
James L. Vallely
Keyword(s):  
Hot Spring ◽  
Geophysical Survey ◽  
Geophysical Data ◽  
Magnetic Survey ◽  
Large Area ◽  
Clark County ◽  
Ore Bodies ◽  
Geophysical Surveys ◽  
Bauxite Ore ◽  
Geophysical Anomalies

Magnetic and gravimetric surveys were conducted over an area of approximately 1400 square miles in the bauxite district of central Arkansas. The primary purpose of these surveys was to discover any possible buried and hitherto unknown syenite masses favorable for the occurrence of bauxite and to determine the approximate position of the buried flanks of the known syenite masses which might offer conditions favorable for the discovery of new ore bodies. These surveys indicated that the various syenite outcrops are domes or bosses on a large batholith and that other similar domes occur on the batholith but do not outcrop. Drilling on the local geophysical anomalies proved the presence of 10 buried domes, but only 2 were found to project above the upper surface of the Midway clays, a requisite of conditions favorable for the occurrence of bauxite ore bodies. The geophysical data indicated the approximate configuration of the buried flanks of the known syenite outcrops, and the portions of these flanks that project above the Midway have now been outlined more accurately by drilling. The geophysical surveys have produced evidence permitting the elimination of a large area as unfavorable for the occurrence of bauxite. Magnetic surveys extending along the Midway‐Wilcox contact from Gurdon in Clark County on the southwest to Searcy in White County on the northeast have proved the improbability of the existence of other syenite masses similar to those found in Pulaski and Saline Counties. A detailed magnetic survey of the Magnet Cove area in Hot Spring County has proved that the syenite mass exposed in that locality is an isolated intrusion and entirely unrelated to those of Pulaski and Saline Counties. This syenite mass does not occur under conditions believed to be favorable for the occurrence of bauxite.

scholarly journals Time-Domain induced Polarization Dipole-Dipole method for the investigation of Sulphide ore - example of some Copper prospects of Nepal

1982 ◽  
Vol 2 (1) ◽  
Author(s):  
R. P. Tandukar ◽  
R. B. Bajracharya
Keyword(s):  
Time Domain ◽  
Induced Polarization ◽  
Time Domain Method ◽  
Sulphide Mineralization ◽  
Sulphide Ore ◽  
Domain Method ◽  
Ore Bodies ◽  
Geophysical Surveys ◽  
Dipole Configuration

The paper presents the results of geophysical surveys carried out using induced polarization (IP) time-domain method with dipole-dipole configuration for the investigation of sulphide ore bodies in Kurule, Wapsa and Kalitar copper prospects of Nepal. IP anomalies were observed in all the prospects which were subsequently checked by drilling. Sulphide mineralization in disseminated forms and in lenses were found. The IP time-domain dipole-dipole method was found successful in the detection of disseminated sulphide mineralization even if its grade was very low.

scholarly journals Integration of geophysics and remote sensing techniques in mapping zones mineralised with disseminated gold and sulphide minerals in Lolgorien, Narok County, Kenya

2021 ◽  
Vol 47 (2) ◽  
pp. 754-768
Author(s):  
Sammy O Ombiro ◽  
Akinade S Olatunji ◽  
Eliud M Mathu ◽  
Taiwo R Ajayi
Keyword(s):  
Remote Sensing ◽  
Mineral Exploration ◽  
Survey Methods ◽  
Induced Polarization ◽  
Reasonable Doubt ◽  
Banded Iron Formations ◽  
Band Ratio ◽  
Sulphide Minerals ◽  
Quartz Veins ◽  
Geophysical Surveys

Even though ground geophysical surveys (especially Induced polarization and resistivity) are applied in mineral exploration, their effectiveness in identification of mineralised zones is often enhanced by integrating other mineral exploration techniques such as remote sensing and geological investigations. Integrating different techniques helps in reducing uncertainty that is often associated with mineral exploration. The methods being integrated also depend on characteristics of mineralisation and those of host rock. In this study, geophysical survey methods (induced polarization and resistivity) were integrated with remote sensing and geological methods to delineate mineralised zones in Lolgorien beyond reasonable doubt. By integrating these methods, it was found that Lolgorien’s gold and sulphide minerals (disseminated minerals) are hosted in massive quartz veins and auriferous quartz veins hosted in Banded Iron Formations. It was also found that this mineralisation was controlled by faults which mainly trend in two directions (NW-SE) and (NE-SW). Keywords: hydrothermal alteration, chargeability, resistivity, band ratio, lineament density

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