Marc A. Vallée

Marc A. Vallée
Geo Data Solutions Inc.

Eng., Ph.D.

About

45
Publications
4,206
Reads
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410
Citations
Additional affiliations
September 2013 - May 2014
CGG
Position
  • Senior Research Geophysicist
September 2006 - August 2013
Fugro World Wide
Position
  • Senior Research Geophysicist
June 1991 - September 1999
Noranda Technology Center
Position
  • Geophysical Engineer

Publications

Publications (45)
Article
We evaluated imaging alteration associated with porphyry copper style mineralisation using aeromagnetic data in the Highland Valley Copper (HVC) district as part of the Natural Sciences and Engineering Research Council of Canada (NSERC) and Canada Mining Innovation Council (CMIC) Footprints project. The first step of the investigation involved cons...
Article
As part of the Natural Sciences and Engineering Research Council of Canada–Canada Mining Innovation Council (NSERC-CMIC) Mineral Exploration Footprints project, three selected magnetic inversion programs (VPmg, MAG3D and VINV) were used to process the same aeromagnetic data set from the Highland Valley Copper district, British Columbia, Canada. In...
Article
Magnetic and gravity inversions are used to create 2D or 3D models of the magnetic susceptibility and density, respectively, using potential field data. Unconstrained inversions generate an output based on mathematical constraints imposed by the inversion algorithm. Constrained inversions integrate lithological, structural, and petrophysical inform...
Article
The creation of 3D models is commonplace in many disciplines. Models are often built from a collection of tessellated surfaces. To apply numerical methods to such models it is often necessary to generate a mesh of space-filling elements that conforms to the model surfaces. While there are meshing algorithms that can do so, they place restrictive re...
Article
Discrete conductor models like sphere and plate were introduced in the 1950s as modelling tools in airborne electromagnetic (AEM) survey interpretation. In the last 20 years, with the development of inversion techniques, they have been integrated into parametric inversion programs. The recent advent of powerful workstations makes them useful tools...
Conference Paper
Discrete object modelling has been used since the beginning of airborne electromagnetic exploration. A recent effort of integrating existing modelling and inversion tools with airborne data shows that simple models are still quite useful for exploration. They can provide simple parameters of a model with minimum a priori and still provide adequate...
Conference Paper
A trend in mining exploration is to increase the number of geophysical parameters collected and interpreted for geological features in a given area. Airborne technology now allows us to simultaneously combine electromagnetic, gravity, aeromagnetic and radiometric surveys. We report the results of a multi-parameter survey conducted in the area of Ka...
Article
Full-text available
Mining exploration was very active during the first decade of the twenty-first century because there were numerous advances in the science and technology that geophysicists were using for mineral exploration. Development came from different sources: instrumentation improvements, new numerical algorithms, and cross-fertilization with the seismic ind...
Article
A useful property of the anomalous magnetic field T associated with some simple geological bodies is that the field is homogeneous with respect to horizontal distance and height. Its horizontal and vertical derivatives are also homogeneous fields so the angle ratio theta of the lateral gradient over the vertical gradient is constant along rays eman...
Article
Exploration for volcanogenic massive sulfides requires good geologic understanding. Geologic knowledge often is limited by a lack of outcrops. This is especially true in Canada under residual glacial covers. Geologic information must therefore be complemented by information obtained using means such as geophysical and geochemical observations. Elec...
Article
Airborne time-domain electromagnetics (ATDEM) methods are regularly used for mining, hydrocarbon, and groundwater exploration. A large quantity of data is collected along survey lines from an aircraft, and there is an incentive to interpret these data in a systematic way. When the geology is appropriate, the use of 1D inversion methods is justified...
Article
We invert time-domain airborne electromagnetic data in such a way as to obtain a model that varies slowly along the profile. This is achieved by modifying a typical one-dimensional inversion algorithm to include lateral constraints. The lateral constraints are included as a roughness matrix that is solved simultaneously with the Jacobian matrix in...
Article
Full-text available
A comparison of data from INPUT, GEOTEM, and MEGATEM airborne electromagnetic (AEM) systems over the Aldermac deposit, Québec, Canada, was undertaken to evaluate the relative efficiency of these systems for the detection of small, deep conductors. The Aldermac orebody was mined between 1933 and 1934 to a depth of 200 m. A deeper mineralized zone wa...
Article
The first book of William Gilbert, De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure (On the Magnet and Magnetic Bodies, and on the Great Magnet the Earth), was published more than 400 years ago in 1600. In this work, Gilbert described experiments on an Earth model to explain the observed magnetic field.
Article
Full-text available
Geomagnetic activity affects aeromagnetic surveys. Geomagnetic variations are quite complex and can be quantified in different ways. A measure of geomagnetic activity that is useful for planning aeromagnetic surveys is the Pc3 pulsation index developed by the Australian Space Weather Agency. Purposeful to developing guidelines for planning aeromagn...
Article
As part of a larger research program, a number of MEGATEM airborne electromagnetic (EM) test flights were flown over the Gallen massive sulfide deposit in northwest Québec. A particularity of this test site is that a major part of the ore body was extracted before the MEGATEM survey. Therefore one of the purposes of this study was to verify the abi...
Article
Full-text available
MEGATEMII airborne electromagnetic data collected over the Iso and New Insco massive sulfide deposits have been modeled using three modeling packages. The EMQ package is a quick inversion tool which indicates that the Iso body is a dipping, plate-like body. The New Insco body is inferred to have a geometry somewhere between a dipping plate and a sp...
Article
Full-text available
A test survey using the MEGATEMII airborne electromagnetic system was flown over the Iso and New Insco massive sulfide orebodies in the Rouyn-Noranda mining camp, Canada. The results were compared with data from historical systems (INPUT, DIGHEM) used to discover the deposits. The historical data show that the two deposits have comparable conductan...
Article
The MEGATEMII system was flown over a test site containing the Gallen deposit. The measured response is consistent with the known geology and shows a rapid decay indicative of a poor conductor. Comparisons with older GEOTEM and INPUT data are problematic, as each dataset was acquired at different stages in the mining of the deposit. Although the GE...
Article
The MEGATEMII system was flown over a site containing the Iso and New Insco deposits. The existing geological information for these sites was compiled and the MEGATEM response was found to be consistent with the geological information and previous geophysical information. The MEGATEM system was found to provide better information than the historica...
Article
Observations have indicated that temporal variations in the magnitude of the geomagnetic field can show a significant decrease in correlation at distances larger than 200 km. We confirm this by a study of geomagnetic measurements from a magneto-telluric survey in Alberta, Canada. Using these data, we estimate the coherence of the total-field magnet...
Article
Predicting the rejection of aeromagnetic data would be a useful tool for aeromagnetic survey planning. To relate aeromagnetic survey requirements to geomagnetic activity monitoring and prediction, we analyzed the relationship between the rejection of aeromagnetic data as it is measured during surveys and the variations in existing geomagnetic indic...
Article
The minimum curvature gridding method is extended to incorporate longitudinal and transverse horizontal gradient information. Hence, the boudinage artifact associated with spatial aliasing is reduced. This in turn allows for better subsequent processing of the aeromagnetic data as well as placement of the locations of discrete features closer to th...
Article
The continuous wavelet transform has been proposed recently for the interpretation of potential field anomalies. Using Poisson wavelets, which are equivalent to an upward continuation of the analytic signal, this technique allows one to estimate the depth of burial of homogeneous field sources and to determine the nature of the source in the form o...
Article
Through computer animations, we outline a prospective 3-D model construction method that builds on a 2.5-D geological mapping and data extraction technique based on vertical and oblique photogrammetry. We use an example from the Canadian Rocky Mountain thrust and fold belt, to demonstrate the method applicability in high relief areas. Photogrammetr...
Article
We compare advantages of currently available digital photogrammetry techniques, combined here with high-resolution imagery datasets, to enhance geological mapping in rugged areas. Examples are presented, illustrating the usefulness of vertical aerial and terrestrial oblique digital photogrammetry, from a prospective hydrocarbon area of the Rocky Mo...
Article
The application of geophysical technology to resource delineation aims to improve the quality of resource/reserve estimates by integrating high-resolution survey methods, geophysical modeling and inversion with three-dimensional representations of geological and mineral deposit data. The use of geophysics can cost-effectively improve a geological i...
Article
Most of the airborne and ground VLF instruments presently used measure the total-field response in addition to field ratios. Results of surveys using these instruments are adversely affected by spatial and temporal variations in the VLF primary field. Until now, the nature of such variations has not been studied from the point of view of geophysica...
Article
Variations in intensity of the primary VLF-EM field have a significant effect on the quality of airborne and ground surveys in which the total field is measured. An analysis of the results of a recent VLF-EM survey and base station records in New Brunswick, Canada, revealed major variations in the primary VLF-EM field due to changes in the transmit...
Article
Full-text available
In this study, we compared the following techniques for inverting TDAEM data: conductivity-depth trans-form (CDT) (Wolfgram and Karlik, 1995) and Zohdy's method (Sattel, 2005) using Fugro proprietary pro-grams and layered-earth inversion using the AIRBEO program from CSIRO. CDT The Conductivity-depth transform (CDT) is a technique developed by Wolf...
Article
Résumé additionnel en anglais. Thèse (Ph. D.)--École polytechnique, 1992. "Thèse présentée en vue de l'obtention du grade de Philosophiæ Doctor (Ph. D.) (Génie minéral)."

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