INPUT AEM Results from Project Pioneer, Manitoba

1975 ◽  
Vol 12 (6) ◽  
pp. 971-981
Author(s):  
A. V. Dyck ◽  
A. Becker ◽  
L. S. Collett
Keyword(s):  
Time Domain ◽  
Vertical Axis ◽  
Structural Features ◽  
Geological Mapping ◽  
Geological Survey ◽  
Scale Model ◽  
Potential Contribution ◽  
Input System ◽  
Interpretation Process ◽  
Airborne Em

The results of an airborne EM survey obtained with an INPUT system flown in the vertical-axis-receiver configuration have been assessed by the Geological Survey of Canada as favorable in terms of their potential contribution to the geological mapping carried out in the Project Pioneer study. Manitoba, Canada. Time-domain scale model profiles over the various conductor arrangements presented here have proven indispensable in the interpretation process. An outstanding example of this is the striking modification to an overburden anomaly made possible by the fortuitous location and dip of a conducting dike model below the overburden. The investigation indicates that during the course of an exploration survey, IN PUT data may be used directly to aid in the mapping of structural features or, indirectly in areas of conductive overburden, if the overburden is structurally controlled.

THEORETICAL RESPONSE OF A TIME‐DOMAIN, AIRBORNE, ELECTROMAGNETIC SYSTEM

Geophysics ◽  
1969 ◽  
Vol 34 (5) ◽  
pp. 729-738 ◽  
Author(s):  
P. H. Nelson ◽  
D. B. Morris
Keyword(s):  
Time Domain ◽  
Computational Procedure ◽  
Response Curves ◽  
Electromagnetic System ◽  
Magnetic Dipoles ◽  
System Calibration ◽  
Input System ◽  
Airborne Electromagnetic ◽  
Airborne Em ◽  
Thickness Parameter

The secondary magnetic field induced by a time‐domain, airborne EM system is calculated by transforming the tabulated mutual impedances of two magnetic dipoles above an earth of homogeneous or layered resistivity structure. The computational procedure is extended to produce response curves useful in interpreting data from a particular system, the Barringer Input system. It is demonstrated that the apparent resistivity can be estimated through use of the receiver channel ratios, a method which is independent of absolute system calibration. Layered earth calculations indicate to what extent conductive overburden cases can be readily distinguished, in terms of the conductivity‐thickness parameter, but separate interpretation of layer resistivity and thickness will require an amplitude‐calibrated flight system.

MODEL RESULTS AND FIELD CHECKS FOR A TIME‐DOMAIN, AIRBORNE EM SYSTEM

Geophysics ◽  
1973 ◽  
Vol 38 (5) ◽  
pp. 845-853 ◽  
Author(s):  
Philip H. Nelson
Keyword(s):  
Time Domain ◽  
Scale Model ◽  
Large Lake ◽  
Response Curves ◽  
Channel Response ◽  
Airborne Em ◽  
Good Agreement

The airborne EM system known as Input was calibrated by applying theoretical homogeneous earth response curves to the response obtained on a flight over a large lake of known resistivity. The calibrated response curves for the conductive overburden case agree with field results in that 1) overburden resistivity in excess of 100 ohm‐m produces negligible deflection on the receiver channels, and 2) the maximum channel response occurs between 1 and 10 ohm‐m overburden resistivity. The calibrated response curves for scale model vertical sheets show fair to good agreement with the response to steeply dipping conductors which have been confirmed with ground‐based EM and drilling. The calibrated scale model results also show: 1) The system possesses a “passband” in conductivity‐thickness, with the first channel peaking around 10 mhos and the later channels at progressively higher values, with the sixth channel peaking at 25 mhos. 2) If a conservative detection cutoff is applied, a vertical conductor will not produce a four‐channel anomaly if it is much deeper than 200 ft subsurface for an aircraft elevation of 400 ft. 3) Channel ratios are constant with depth and also fairly constant over the 10–100 mhos range in conductivity‐thickness.

Exploration history and place names of northern East Greenland

1969 ◽  
Vol 21 ◽  
pp. 1-368 ◽  
Author(s):  
Anthony K. Higgins
Keyword(s):  
20Th Century ◽  
19Th Century ◽  
Geological Mapping ◽  
Geological Survey ◽  
The Arctic ◽  
Place Names ◽  
East Greenland ◽  
New Name ◽  
Systematic Compilation

The first recorded landing by Europeans on the coast of northern East Greenland (north of 69°N) was that of William Scoresby Jr., a British whaler, in 1822. This volume includes a chronological summary of the pioneer 19th century exploration voyages made by British, Danish, Norwegian, Swedish, French and German expeditions – all of whom reported that the region had previously been occupied by the Inuit or Eskimo; also included are brief outlines of the increasing number of government and privately sponsored expeditions throughout the 20th century, whose objectives included cartography, geology, zoology, botany, trapping and the ascent of the highest mountain summits. In 1934 the Place Name Committee for Greenland was established, the tasks of which included a review of all place names hitherto recorded on published maps of Greenland, their formal adoption in danicised form, and the approval or rejection of new name proposals. In northern East Greenland, by far the largest numbers of new place names were those proposed by scientists associated with Lauge Koch's geological expeditions that lasted from 1926 until 1958. This volume records the location and origin of more than 3000 officially approved place names as well as about 2650 unapproved names. The author's interest in the exploration history and place names of northern East Greenland started in 1968, when the Geological Survey of Greenland initiated a major five-year geological mapping programme in the Scoresby Sund region. Systematic compilation of names began about 1970, initially with the names given by William Scoresby Jr., and subsequently broadened in scope to include the names proposed by all expeditions to northern East Greenland. The author has participated in 16 summer mapping expeditions with the Survey to northern East Greenland. Publication of this volume represents the culmination of a lifetime working in the Arctic.

The year in focus, 2000

2001 ◽  
pp. 7-10
Author(s):  
Kai Sørensen
Keyword(s):  
Geological Mapping ◽  
Geological Survey ◽  
Seismic Survey ◽  
East Greenland ◽  
Major Field ◽  
Original Series ◽  
West Greenland ◽  
Level Of Activity ◽  
Field Activity ◽  
Year 2000

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Sørensen, K. (2001). The year in focus, 2000. Geology of Greenland Survey Bulletin, 189, 7-10. https://doi.org/10.34194/ggub.v189.5148 _______________ The year 2000 was unusual in that it lacked major field activity directly involved with the systematic geological mapping of Greenland. However, field activities were again many and varied, including a successful highresolution seismic survey offshore central West Greenland, and a joint Geological Survey of Denmark and Greenland (GEUS) – Danish Lithosphere Centre (DLC) project centred on Kangerlussuaq in southern East Greenland. Of the Survey’s 354 personnel, 93 were allocated to Greenland-related activities (Table 1). The Greenland level of activity in 2000, both in Copenhagen and in the field, thus compared favourably with that of 1999.

3-D Time-Domain Airborne EM Inversion for a Topographic Earth

2020 ◽  
pp. 1-13
Author(s):  
Yanfu Qi ◽  
Xiu Li ◽  
Changchun Yin ◽  
Huaiyuan Li ◽  
Zhipeng Qi ◽  
...  
Keyword(s):  
Time Domain ◽  
Airborne Em

Volcanoes geological mapping and structural geology with UAS High Resolution Digital Terrain Model : the Kuei-Shan Tao case example (Eastern Taiwan).

2021 ◽  
Author(s):  
Benoit Deffontaines ◽  
Kuo-Jen Chang ◽  
Samuel Magalhaes ◽  
Gérardo Fortunato
Keyword(s):  
High Resolution ◽  
Okinawa Trough ◽  
Volcanic Rocks ◽  
Digital Terrain Model ◽  
Structural Features ◽  
Point Of View ◽  
Geological Mapping ◽  
Lava Flows ◽  
Aerial Photographs ◽  
Structural Scheme

<p>Volcanic areas in the World are often difficult to map especially in a structural point of view as (1) fault planes are generally covered and filled by more recent lava flows and (2) volcanic rocks have very few tectonic striations. Kuei-Shan Tao (11km from Ilan Plain – NE Taiwan) is a volcanic island, located at the soutwestern tip of the South Okinawa trough (SWOT). Two incompatible geological maps had been already published both lacking faults and structural features (Hsu, 1963 and Chiu et al., 2010). We propose herein not only to up-date the Kuei-Shan Tao geological map with our high resolution dataset, but also to create the Kuei-Shan Tao structural scheme in order to better understand its geological and tectonic history.</p><p>Consequently, we first acquired aerial photographs from our UAS survey and get our new UAS high resolution DTM (HR UAS-DTM hereafter) with a ground resolution <10cm processed through classical photogrammetric methods. Taking into account common sense geomorphic and structural interpretation and reasoning deduced form our HR UAS-DTM, and the outcropping lithologies situated all along the shoreline, we have up-dated the Kuei-Shan Tao geological mapping and its major structures. To conclude, the lithologies (andesitic lava flows and pyroclastic falls) and the new structural scheme lead us to propose a scenario for both the construction as well as the dismantling of Kuei-Shan Tao which are keys for both geology and geodynamics of the SWOT.</p>

The airborne electromagnetic discovery of the Detour zinc‐copper‐silver deposit, northwestern Québec

Geophysics ◽  
1981 ◽  
Vol 46 (9) ◽  
pp. 1278-1290 ◽  
Author(s):  
L. E. Reed
Keyword(s):  
Volcanic Rocks ◽  
Channel Response ◽  
Copper Sulfides ◽  
Input System ◽  
Diamond Drill ◽  
Geophysical Surveys ◽  
Airborne Electromagnetic ◽  
Airborne Em ◽  
Two Bodies

In June 1974, a diamond drill operated for Selco Mining Corp. intersected zinc‐copper sulfides in Brouillan Township in northwestern Québec. To date, two bodies have been outlined. These bodies were discovered during a ground follow‐up of a Mark VI Input® electromagnetic (EM) survey. The Input survey covered an area selected on the basis of regional geology and local outcrops of acid volcanic rocks. Conductors were identified that appeared to be associated with potentially favorable geology. They were selected for ground follow‐up. One was the discovery zone. The airborne responses over the zone were less encouraging than those often observed over highly conductive massive sulfides. The low apparent conductivity‐thickness (5 mhos) was suggestive of conductive overburden. However, the character of the profiles suggested a bedrock source. Ground geophysical confirmation identified a drill target. Subsequent to the discovery, more intensive geophysical surveys, both ground and airborne, were carried out. The best EM response suggested a confined source within a much larger mineralized halo. Weaker ground EM response from the halo correlated with the early channel response of the Input system. An airborne EM survey conducted in 1958 over the same area identified both conductive zones. However, they were not followed up. Only with later advances in exploration philosophy, geologic appreciation, and instrumentation were the conductive zones recognized as viable exploration targets.

scholarly journals Wandel Sea Basin: basin analysis – a summary

1995 ◽  
Vol 165 ◽  
pp. 42-48
Author(s):  
E Håkansson ◽  
L Stemmerik
Keyword(s):  
Financial Support ◽  
Research Council ◽  
Science Research ◽  
Field Work ◽  
Geological Mapping ◽  
Basin Analysis ◽  
Geological Survey ◽  
Natural Science Research Council ◽  
Field Season ◽  
North Greenland

In 1991 a three year research project was initiated by the Geological Institute, University of Copenhagen with financial support from the Ministry of Energy, the Danish Natural Science Research Council and the Carlsberg Foundation. The 'Wandel Sea Basin: basin analysis' project was carried out in collaboration with the Geological Survey of Greenland and included field work in North Greenland; in eastern Peary Land in 1991 and Amdrup Land in 1993 (Fig. 1; Hakansson et al., 1994). The project is a continuation of earlier investigations in the Wandel Sea Basin carried out during geological mapping of North Greenland by the Geological Survey of Greenland in 1978–1980 and during later expeditions to the area (e.g. Hakansson, 1979; Hakansson et al., 1981, 1989, 1991, 1994). Hydrocarbon related studies of the Wandel Sea Basin were continued during the 1994 field season (Stemmerik et al., this report).

scholarly journals The Skjoldungen map sheet: completion of the 1:500 000 geological mapping of South-East Greenland

1991 ◽  
Vol 152 ◽  
pp. 30-31
Author(s):  
J.C Escher
Keyword(s):  
Geological Mapping ◽  
The Other ◽  
Geological Survey ◽  
East Greenland ◽  
Metamorphic Development ◽  
Geological Map ◽  
Map Series

The publication of the 1:500 000 Skjoldungen map sheet (Escher, 1990; Fig. 1) marks the completion of the Geological Survey of Greenland's (GGU's) reconnaissance mapping activities in South-East Greenland. A descriptive text to the map is under preparation. All of South-East Greenland between Kap Farvel (59° 00´N) and Mesters Vig (72° 00´N) is now covered by sheets of the 1:500 000 geological map series of Greenland. Five sheets in the series (nos 5,6,9, 10 and 11) remain to be published (Fig. 1); the Thule map sheet (sheet 5) will be printed in the course of 1991, and sheet 10 is under compilation. The presentation of the Skjoldungen map is somewhat different from that of the other 1:500 000 maps inthe series. In addition to traditional lithological information, an effort has been made to show the tectonic/metamorphic development of the region during the Archaean and Proterozoic.

scholarly journals 3-DIMENSIONAL GEOLOGICAL MAPPING AND MODELING ACTIVITIES AT THE GEOLOGICAL SURVEY OF NORWAY

2015 ◽  
Vol XL-2/W4 ◽  
pp. 11-16 ◽  
Author(s):  
A. Jarna ◽  
A. Bang-Kittilsen ◽  
C. Haase ◽  
I. H. C. Henderson ◽  
F. Høgaas ◽  
...  
Keyword(s):  
3D Visualization ◽  
Three Dimensional ◽  
Mineral Resources ◽  
Geological Mapping ◽  
Geological Survey ◽  
Marine Geology ◽  
Data Infrastructure ◽  
3 Dimensional ◽  
3D Data ◽  
Wide Range

Geology and all geological structures are three-dimensional in space. Geology can be easily shown as four-dimensional when time is considered. Therefore GIS, databases, and 3D visualization software are common tools used by geoscientists to view, analyse, create models, interpret and communicate geological data. The NGU (Geological Survey of Norway) is the national institution for the study of bedrock, mineral resources, surficial deposits and groundwater and marine geology. The interest in 3D mapping and modelling has been reflected by the increase of number of groups and researches dealing with 3D in geology within NGU. This paper highlights 3D geological modelling techniques and the usage of these tools in bedrock, geophysics, urban and groundwater studies at NGU, same as visualisation of 3D online. The examples show use of a wide range of data, methods, software and an increased focus on interpretation and communication of geology in 3D. The goal is to gradually expand the geospatial data infrastructure to include 3D data at the same level as 2D.

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