scholarly journals Drone-based electromagnetic survey system for geophysical applications

2022 ◽  
Vol 2 ◽  
pp. 3
Author(s):  
Markku Pirttijärvi ◽  
Ari Saartenoja ◽  
Pekka Korkeakangas
Keyword(s):  
Mineral Exploration ◽  
Theoretical Background ◽  
Geological Mapping ◽  
Current Version ◽  
Horizon 2020 ◽  
Large Loop ◽  
Maximum Payload ◽  
Geotechnical Investigations ◽  
Survey System ◽  
Airborne Em

Geophysical electromagnetic (EM) methods are used in geological mapping, mineral exploration, groundwater studies and geotechnical investigations. Airborne EM methods have the benefit of avoiding terrain obstacles such as lakes, rivers, swamps, and ravines. Compared to manned aircrafts, drones or unmanned aerial vehicles (UAVs) have benefits of their own. Drone-based surveys are versatile, fast to deploy, economical and ecologically more friendly. Presently, magnetic surveying is the only geophysical method that is routinely conducted with drones. The modest maximum payload limit of drones imposes severe restrictions on the applicability of other methods including EM and radiometric methods, for example. Finnish company, Radai Ltd has been developing Louhi, a novel drone-based frequency-domain EM survey system, in an EU funded Horizon 2020 project NEXT – New Exploration Technologies. The EM system has two operation options – the first uses a large loop on the ground as an EM source and the other uses a small portable EM transmitter loop. Both systems utilize a stand-alone and light-weight three-component EM receiver that can be towed by a drone. This article presents the theoretical background of the EM methods, the solution developed by Radai Ltd, the current version of the EM device, and results from field and flight tests that demonstrate the applicability of the drone-based EM system under development.

Airborne geophysical surveys in Greenland – 1996 update

1997 ◽  
pp. 75-79
Author(s):  
Robert W. Stemp
Keyword(s):  
Mineral Exploration ◽  
Geological Mapping ◽  
Digital Data ◽  
Magnetic Survey ◽  
Aeromagnetic Survey ◽  
West Greenland ◽  
South West ◽  
Geophysical Surveys ◽  
The Government ◽  
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, for example: Stemp, R. W. (1997). Airborne geophysical surveys in Greenland – 1996 update. Geology of Greenland Survey Bulletin, 176, 75-79. https://doi.org/10.34194/ggub.v176.5069 _______________ Two major airborne geophysical surveys were carried out in 1996, the third year of a planned five-year electromagnetic and magnetic survey programme (project AEM Greenland 1994–1998) financed by the Government of Greenland, and the second year of an aeromagnetic survey programme (project Aeromag) jointly financed by the governments of Denmark and Greenland; both projects are managed by the Geological Survey of Denmark and Greenland (GEUS). The two 1996 surveys were: 1) Project Aeromag 1996 in South-West and southern West Greenland;2) Project AEM Greenland 1996 in South-West Greenland. All areas surveyed and planned for future surveys as of March 1997 are shown in Figure 1. Results of both the 1996 surveys were released in March 1997, as a continuation of a major effort to make high quality airborne geophysical data available for both mineral exploration and geological mapping purposes. The data acquired are included in geoscientific databases at GEUS for public use; digital data and maps may be purchased from the Survey. The main results from the 1996 surveys are described in Thorning & Stemp (1997) and Stemp (1997). Two further new airborne surveys have already been approved for data acquisition during the 1997 field season, with subsequent data release in March 1998. A summary of all surveys completed, in progress or planned since the formal inception of project AEM Greenland 1994–1998 is given in Table 1. The programme was expanded to include a separate regional aeromagnetic survey in 1995, provisionally for 1995–1996, with extension subject to annual confirmation and funding.

Observations of the Earth’s resources

1969 ◽  
Vol 308 (1493) ◽  
pp. 173-182 ◽  
Keyword(s):  
Mineral Exploration ◽  
Geological Mapping ◽  
The Other ◽  
Ground Control ◽  
Great Contribution ◽  
Know How ◽  
Control Information ◽  
The World ◽  
The One ◽  
Effective Development

In attempting to present some observations on the kind of information on the Earth’s resources which may be obtained from spacecraft and space satellites, I think I should explain that I speak as a geographer with research interests in the field of biogeography/geobotany where I have been concerned with the use of vegetation in mineral exploration work and in the assessment of land potential for agricultural and other uses. In the course of this work I have come to appreciate major problems of regional or even continental dimensions and have become aware of the great potential offered by suitably equipped Earth resources satellites for providing information which would assist their solution. At the same time I have come to recognize the great contribution which Earth resources satellites can make in the fields of agriculture, forestry and conservation, topographical and geological mapping, hydrology, oceanography, land use and urban planning, to mention but a few. As a setting for my subsequent remarks I would like to state what I believe to be the relative positions of the U. S. A. and the U. S. S. R. on the one hand and this country and certain West European countries on the other with regard to the acquisition of information from Earth resources satellites. America and Russia have led the world in space research. They have the resources, the facilities and the technical know-how for placing spacecraft and satellites in orbit. For the effective development of Earth resources satellites, however, ground control information is essential. Here this country, together with member and former member countries of the Commonwealth possesses a body of people scattered through universities, government departments and organizations, commerce and industry whose firsthand knowledge of remote terrain in many parts of the world is unrivalled. This knowledge harnessed into an Earth resources satellites programme could enable this country to make a leading contribution to the development of the less developed parts of the world and at the same time materially assist the economy of this country.

Geology of the Eminescu (H-09) quadrangle: Mapping status

2021 ◽  
Author(s):  
Mayssa El Yazidi ◽  
Gloria Tognon ◽  
Valentina Galluzzi ◽  
Lorenza Giacomini ◽  
Matteo Massironi
Keyword(s):  
Incidence Angle ◽  
Central Peak ◽  
Geological Mapping ◽  
Geologic Mapping ◽  
Linear Features ◽  
Horizon 2020 ◽  
The Status ◽  
Global Mapping ◽  
Dual Imaging ◽  
Degradation Degree

<p><strong>Abstract</strong></p> <p>The coordinated Mercury’s global mapping project (Galluzzi et al. (2021), aims at delivering quadrangle geological maps for the entire surface of Mercury by using the available basemaps derived from the NASA MESSENGER Mercury Dual Imaging Systems (MDIS) images. The NASA MESSENGER mission was able to cover the surface of Mercury with an average resolution of 200 m/px globally. This allows to produce a series of 1:3M regional geologic maps to be used in support to the ESA/JAXA BepiColombo mission. Here we present the status of the geologic mapping of the Eminescu (H-09) quadrangle, which covers the area between latitudes 22.5°N, -22.5°S and longitudes 72°E, 144°E. The selection of this quadrangle was based on its wealth of many interesting features (e.g., Beagle Rupes, hollow deposits on Eminescu crater, pyroclastic deposits at the margin of the Caloris basin) and on the color variability between the different terrain types that allows to reconstruct the geological history of H-09.</p> <p><strong>Methods</strong></p> <p>In this work, we used the available basemaps derived from the MESSENGER MDIS instrument images, such as the monochrome morphology image mosaics at high- and low-incidence angle (BDR, HIE, HIW and LOI) with a resolution of 166 m/px, together with the enhanced-color and 3-color global mosaics, having a resolution of 665 m/px.</p> <p>The chosen 1:3M output scale is achieved by mapping at an average scale of 1:400k, which is appropriate for the used basemaps. For the symbology, we applied, and in some cases revisited, the Federal Geographic Data Committee (FGDC) and the United Stated Geographic System (USGS) recommendations. The classification of the crater types was based on their diameter, degradation degree and superposition order. The crater's ejecta, central peak, and floor morphology (hummocky or smooth) were distinguished and mapped only for craters larger than 20 km, to avoid the saturation of map features. The terrain units were identified by means of morphology and crater-density, by distinguishing between smooth, intermediate and intercrater plains. We used different symbologies for geological contacts and linear features by distinguishing between certain and approximate contacts, or certain and uncertain/hidden structures, respectively. In particular, the linear features layer encompasses morphologies such as crater rims (up to 5 km in diameter), fault scarps, wrinkle ridges and volcanic vents. The variability in color and albedo was digitized within a surface features polygon layer (e.g., dark material, bright material, and hollow clusters). We did not consider details smaller than 4 km, nor linear features whose distance was smaller than this same threshold to avoid map readability issues.</p> <p><strong>Results</strong></p> <p>The mapping of H-09 is still in progress. The preliminary analysis shows an intriguing morphology related to endogenic and exogenic processes, where intensive tectonic and cratering structures constitute together the main geological events that provided the heterogeneity of terrains in the quadrangle. The tectonic events were probably driven by global cooling, however, we found both compressive and tensional tectonic features on the surface. Hollow clusters are spread all over the quadrangle in different sizes and locations (e.g., crater floors, central peaks). The Eminescu crater located in H-09, between latitudes 12.3°N, 8.8°N  and longitudes 115.9°E, 112.2°E in H-09, is a relatively young crater on Mercury's surface and is characterized by extensive ejecta for one radius from the crater's rim and a recently hollowed central peak. These features and its enhanced color variability will probably require a higher-resolution study of this crater by integrating the geomorphological map with spectral data.</p> <p>This map will be the first geological product for this region with such a scale. Once the mapping is completed, we will be able to determine the absolute ages of the units to classify the terrains in chronological order and provide a complete geological and morphological analysis to understand the geological evolution of the quadrangle. Therefore, through the mapping of H-09 we aim at supporting the ESA/JAXA BepiColombo mission to Mercury by targeting all interesting features and contributing to the investigation and the understanding of Mercury.</p> <p><strong>Keywords: </strong>Mercury (planet), Eminescu Quadrangle, Geological Mapping, MESSENGER, MDIS.</p> <p><strong>Acknowledgements</strong></p> <p>This research has been supported by European Union’s Horizon 2020 under grant agreement N° 776276-PLANMAP.</p> <p><strong>References</strong></p> <p>Galluzzi et al. (2021), PGM Meeting 2021, LPI Contrib. No. 2610.</p>

Systematic survey of K, Th, and U signatures in airborne radiometric data from Australian meteorite impact structures: Possible causes of circular features and implications

2021 ◽  
Author(s):  
Cheikh Ahmadou Bamba Niang ◽  
David Baratoux ◽  
Dina Pathé Diallo ◽  
Pierre Rochette ◽  
Mark W. Jessell ◽  
...  
Keyword(s):  
Case Studies ◽  
Crustal Deformation ◽  
Seismic Reflection ◽  
Gamma Ray ◽  
Mineral Exploration ◽  
Geological Mapping ◽  
Impact Event ◽  
Systematic Survey ◽  
The Impact ◽  
Radiometric Data

ABSTRACT Airborne radiometric (gamma-ray) data provide estimates of the concentrations of potassium (K), thorium (Th), and uranium (U) in soil, regolith, and bedrock. Radiometric data constitute an important source of geochemical information, commonly used in mineral exploration and for geological mapping of Earth and other planets. Airborne radiometric data have rarely been applied to the exploration and analyses of impact structures, in contrast with other conventional geophysical tools (e.g., gravimetry, magnetism, and seismic reflection/refraction). This work represents the first systematic survey of the K, Th, and U radiometric signatures of Australian impact structures, based on the continent-wide airborne radiometric coverage of Australia. We first formulated several hypotheses regarding the possible causes of formation of circular radiometric patterns associated with impact structures. Then, the radiometric signatures of 17 exposed impact structures in Australia were documented. Our observations confirmed the supposition that impact structures are commonly associated with circular radiometric patterns. We then selected the five structures with the most prominent circular radiometric patterns (Gosses Bluff, Lawn Hill, Acraman, Spider, and Shoemaker), and we discuss the possible origin of these anomalies. Based on these five case studies, we argue that such patterns result from either crustal deformation induced by the impact event and/or from postimpact superficial processes controlled by the crater topography. This work also suggests that airborne radiometric data may be useful, in combination with other geophysical tools, in the search for new possible impact structures.

The aeromagnetic survey program of the Geological Survey of Canada: contribution to regional geological mapping and mineral exploration

1993 ◽  
Vol 30 (2) ◽  
pp. 243-260 ◽  
Author(s):  
D. J. Teskey ◽  
P. J. Hood ◽  
L. W. Morley ◽  
R. A. Gibb ◽  
P. Sawatzky ◽  
...  
Keyword(s):  
Mineral Exploration ◽  
National Research Council ◽  
High Sensitivity ◽  
Geological Mapping ◽  
Geological Survey ◽  
The Arctic ◽  
Navigation Systems ◽  
Current Standard ◽  
Private Industry ◽  
Aeromagnetic Survey

The aeromagnetic survey operations of the Geological Survey of Canada (GSC) began in 1946, utilizing a magnetometer in a bird system towed by a Royal Canadian Air Force Anson. Subsequent early operations were carried out by the GSC-operated Canso and Aero Commander aircraft. In 1961, the GSC in-house survey team formed the nucleus of a contract surveys group set up to monitor a new program established to complete the aeromagnetic mapping of the Canadian Shield in 12 years on a cost-sharing basis with the provinces. Today, surveys are carried out under contract by light twin-engine aircraft such as the Cessna 404 and even, in some cases, single-engine aircraft that utilize compact computer-controlled data acquisition and navigation systems and inboard magnetometer installations. Early systems were capable of resolution of only a few nanoteslas (nT) compared to the current standard of 0.1 nT or less, and flight path positioning with 35 mm film and photomosaics or topographical maps was extremely challenging. Despite these limitations, the careful selection of survey parameters and attention given to quality control have resulted in a world-class aeromagnetic data base that has contributed significantly to regional geological mapping and to mineral and oil exploration in Canada. Concurrently, the GSC carried out research programs into the development of instrumentation and into processing, interpretation, and enhancement techniques. In 1968, the GSC acquired its own platform, a Beechcraft B80 Queenair, which was used to develop high-sensitivity techniques, and an inboard gradiometer system, which was transferred to private industry in 1983. The GSC, in cooperation with the Flight Research Laboratory of the National Research Council of Canada, has also conducted a program of research into magnetometry and navigation combined with aeromagnetic studies of the Arctic since 1962.

Effect of tropical weathering on electrical and electromagnetic measurements

Geophysics ◽  
1979 ◽  
Vol 44 (1) ◽  
pp. 69-88 ◽  
Author(s):  
G. J. Palacky ◽  
Kiyoshi Kadekaru
Keyword(s):  
Electrical Properties ◽  
Mineral Exploration ◽  
Annual Rainfall ◽  
Tropical Regions ◽  
Rock Types ◽  
Electromagnetic Measurements ◽  
Weathered Layer ◽  
Efficient Exploration ◽  
Effective Use ◽  
Airborne Em

Electrical properties of the weathered layer in tropical regions of Brazil were investigated by means of resistivity soundings, airborne, and ground electromagnetic measurements. Five case histories illustrate how changes of climate, lithology, and geomorphology affect geophysical measurements. In humid and subhumid tropical regions (annual rainfall over 650 mm) the weathered layer is between 10 and 80 m thick and moderately conductive. Results from one region (Minas Gerais) indicate that excessive depth of weathering and leaching of massive sulfides, rather than the conductivity of overburden, present the greatest obstacle to effective use of airborne EM methods in mineral exploration. Seasonal variations of precipitation cause changes in soil resistivity, but such changes are not apparent in the underlying weathered layer. In semiarid and temperate regions of Brazil, the weathered layer is 10 to 20 m thick and regional airborne EM surveys are an efficient exploration tool. In all regions, the degree of weathering depends upon lithology and, in several areas, anomaly patterns obtained from airborne EM surveys correlate well with the surface geologic map. However, when comapring electrical properties of similar rock types among regions of the same climatic type, a considerable variation is observed. It seems that also geomorphology plays an important role in weathering. A careful interpretation of airborne EM data is necessary to distinguish anomalies caused by the weathered layer from those due to underlying conductors. Highly conductive, saline alluvia, which cause strong EM anomalies in Australia, were encountered (sporadically) in only one region of Brazil, the semiarid Valley of Curaçá, Bahia.

Making exploration of underground flooded mines a reality - the UNEXUP solution

2020 ◽  
Author(s):  
Márcio Pinto ◽  
Norbert Zajzon ◽  
Luís Lopes ◽  
Balazs Bodo ◽  
Stephen Henley ◽  
...  
Keyword(s):  
Raw Materials ◽  
Mineral Exploration ◽  
Business Case ◽  
Primary Objective ◽  
Economic Feasibility ◽  
Mineral Deposits ◽  
Self Awareness ◽  
Design Development ◽  
Horizon 2020 ◽  
Mine Development

<p>The UNEXUP project, funded under EIT Raw Materials, is a direct continuation of the Horizon 2020 UNEXMIN project. While in UNEXMIN efforts were made towards the design, development and testing of an innovative exploration technology for underground flooded mines, in UNEXUP the main goal is to push the UNEXMIN technology into the market, while further improving the system’s hardware, software and capabilities. In parallel, the aim is to make a strong business case for the improved UNEXUP technology, as a result of tests and data collection from previous testing. Improvements to the UX-1 research prototypes will raise technology readiness levels from TRL 6, as verified at the end of the UNEXMIN project, to TRL 7/8 by 2022. A "real service-to-real client" approach will be demonstrated, supporting mineral exploration and mine surveying efforts in Europe with unique data from flooded environments that cannot be obtained without high costs, or risks to human lives, in any other ways.</p><p>The specific purpose of UNEXUP is to commercially deploy a new raw materials exploration / mine mapping service based on a new class of mine explorer robots, for non-invasive resurveying of flooded mines. The inaccessibility of the environment makes autonomy a critical and primary objective of the project, which will present a substantial effort in resurveying mineral deposits in Europe where the major challenges are the geological uncertainty, and technological / economic feasibility of mine development. The robot’s ability to gather high-quality and high-resolution information from currently inaccessible mine sites will increase the knowledge of mineral deposits in Europe, whilst decreasing exploration costs – such as the number of deep exploration drillholes needed. This can potentially become a game changing technology in the mining panorama, where the struggle for resources is ever increasing.</p><p>On the technical side, a fourth robot, modular in nature, will be added to the current multi-robot platform, providing additional functionalities to the exploration system, including better range and depth performance. Hardware and software upgrades, as well as new capabilities delivered by the platform will greatly extend the usefulness of the platform in different environments and applications. Among these: rock sampling, better data acquisition and management, further downsizing, extended range, improved self-awareness and decision making, mature post-processing (such as the deployment of 3D virtual reality models), ability to rescue other robots, and interaction with the data will be targeted during the next years. Upgrading the overall technology with these tools, and possibly additional ones, will allow the system to operate with more reliability and security, with reduced costs.</p><p>These added functions arise from different stakeholders’ feedbacks from the UNEXMIN project. UNEXUP targets parties from the mining, robotics and mineral exploration sectors, as well as all other sectors that have any kind of underwater structure that needs to be surveyed – caves, underground reservoirs, water pipelines and fisheries are among them. For the purpose of exploitation of the technology, a joint company was founded, “UNEXMIN GeoRobotics Ltd”, which is part of the UNEXUP consortium, and is responsible for selling the service to the market.</p>

scholarly journals Geophysical Assessment of Subsurface Conditions at Proposed Building Sites: Implications for Foundation Failure and Building Collapse

2018 ◽  
Vol 64 (3) ◽  
pp. 8-20
Author(s):  
Stephen Oluwafemi Ariyo ◽  
Julius Ogunmola Fatoba ◽  
Olateju O. Bayewu ◽  
Kamaldeen Olakunle Omosanya ◽  
Muhedeen Ajibola Lawal
Keyword(s):  
Geological Mapping ◽  
Geophysical Investigation ◽  
Building Collapse ◽  
Resistivity Imaging ◽  
Geotechnical Investigations ◽  
Weathered Layer ◽  
Electrical Sounding ◽  
2D Resistivity Imaging ◽  
2D Resistivity ◽  
Wenner Array

Abstract Building collapse has been a recurrent environmental hazard in Nigeria in the last two decades. This is a corollary of inadequate foundation investigation prior to construction, poor government policies, and general lack of awareness on the importance of geophysical and geotechnical investigations. In this study, geological mapping and detailed geophysical investigation using Electrical Resistivity Imaging (ERI) and Vertical Electrical Sounding (VES) were carried out to understand the suitability of proposed building sites at the main campus of the Olabisi Onabanjo University (OOU), Ago-Iwoye, Nigeria for construction. Both Wenner array and dipole-dipole were used for profiling and Schlumberger for sounding. Four transverses and VES were used in each of the three areas investigated. Our results show that the subsurface of the study areas is underlain by Precambrian basement rock of Nigeria. Rocks in the study area include banded gneiss, porphyroblastic gneiss, biotite-hornblende granite and quartzite schist. The sounding stations across the three areas and 2D resistivity imaging revealed three principal geoelectric layers, the topsoil, the weathered layer and the fractured/fresh basement with varied resistivity values for each layers. At the VES stations, the three geoelectric layers have resistivity values of 62 to 1182 Ωm, 3.2 to 1360Ωm and 87 to 4680 Ωm. On the 2D resistivity imaging profiles, the resistivity of the three layers varies from 2 to 1182 Ωm, 30to 1360 Ωm, and 40 to 2904 Ωm for the topsoil, the weathered basement, and fractured/fresh bedrock. Our work demonstrates that some of the proposed sites are structurally incompetent for engineering or foundation purposes. Excavation of the topsoil and reinforcement are required to sustain the proposed structures.

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