Physical properties and seismic imaging of massive sulfides

Geophysics ◽  
2000 ◽  
Vol 65 (6) ◽  
pp. 1882-1889 ◽  
Author(s):  
Matthew H. Salisbury ◽  
Bernd Milkereit ◽  
Graham Ascough ◽  
Robin Adair ◽  
Larry Matthews ◽  
...  
Keyword(s):  
Physical Properties ◽  
Seismic Imaging ◽  
Country Rock ◽  
Imaging Techniques ◽  
Geometric Constraints ◽  
Eastern Canada ◽  
Massive Sulfides ◽  
Ore Bodies ◽  
Text Density ◽  
Representative Samples

Laboratory studies show that the acoustic impedances of massive sulfides can be predicted from the physical properties ([Formula: see text], density) and modal abundances of common sulfide minerals using simple mixing relations. Most sulfides have significantly higher impedances than silicate rocks, implying that seismic reflection techniques can be used directly for base metals exploration, provided the deposits meet the geometric constraints required for detection. To test this concept, a series of 1-, 2-, and 3-D seismic experiments were conducted to image known ore bodies in central and eastern Canada. In one recent test, conducted at the Halfmile Lake copper‐nickel deposit in the Bathurst camp, laboratory measurements on representative samples of ore and country rock demonstrated that the ores should make strong reflectors at the site, while velocity and density logging confirmed that these reflectors should persist at formation scales. These predictions have been confirmed by the detection of strong reflections from the deposit using vertical seismic profiling and 2-D multichannel seismic imaging techniques.

Seismic properties of the Voisey’s Bay massive sulfide deposit: Insights into approaches to seismic imaging

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC59-WC68 ◽  
Author(s):  
Deanne Duff ◽  
Charles Hurich ◽  
Sharon Deemer
Keyword(s):  
Physical Properties ◽  
Seismic Imaging ◽  
Imaging Technique ◽  
Imaging Techniques ◽  
Massive Sulfide ◽  
Mineral Deposit ◽  
Sulfide Deposit ◽  
Seismic Velocities ◽  
Sulfide Ores ◽  
Host Rocks

Seismic methods offer significant potential advantages for minerals exploration over more traditional geophysical techniques because of the comparatively high resolution of seismic imaging. This is particularly true as minerals exploration is required to explore deeper to find resources. However, adaptation of seismic imaging techniques to the complex crystalline targets common in the mining environment requires a thorough understanding of the physical properties of the specific combination of ore and host rocks under consideration to choose an appropriate imaging technique. Analysis of the sulfide ores and associated host rocks from the Voisey’s Bay nickel-copper-cobalt deposit indicates that in the pyrrohotite-pentlandite-rich but pyrite-poor assemblage at Voisey’s Bay, seismic velocities are significantly lower ([Formula: see text]) than either the felsic or mafic host rocks ([Formula: see text] and [Formula: see text]). This observation is in contrast with pyrite-rich massive sulfide ores that have velocities that are significantly higher than typical host rocks. The large velocity contrast between the Voisey’s Bay ores and their host rocks makes them good targets for tomographic imaging. However, due to the trade-off between the low velocities and high densities of the Voisey’s Bay sulfides, acoustic impedance contrasts can be quite modest making them less attractive for seismic reflection imaging. Detailed analysis of two different mineralized zones at Voisey’s Bay further demonstrated that, depending on the limiting signal-to-noise ratio, the choice of an effective seismic imaging technique is not universal across a mineral deposit and may be affected by subtle variations in sulfide mineralogy and by the structural/magmatic setting. Our analysis clearly indicated that knowledge of physical properties and geologic setting is critical to the choice of which seismic technique to apply in a given exploration setting.

Comparison of Some Seismic Imaging Techniques

1980 ◽  
pp. 737-760
Author(s):  
Thomas T. Hu ◽  
Keith Wang ◽  
Fred Hilterman
Keyword(s):  
Seismic Imaging ◽  
Imaging Techniques

Salt deformation modeling through the use of enhanced seismic imaging techniques

1994 ◽  
Vol 13 (8) ◽  
pp. 844-848 ◽  
Author(s):  
William M. House ◽  
John A. Pritchett
Keyword(s):  
Seismic Imaging ◽  
Imaging Techniques

scholarly journals Experimental Investigation on the Influence of Target Physical Properties on an Impinging Plasma Jet

Plasma ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 369-379 ◽  
Author(s):  
Emanuele Simoncelli ◽  
Augusto Stancampiano ◽  
Marco Boselli ◽  
Matteo Gherardi ◽  
Vittorio Colombo
Keyword(s):  
Physical Properties ◽  
High Speed ◽  
Gas Flow ◽  
Light Emission ◽  
Fluid Dynamic ◽  
Imaging Techniques ◽  
Plasma Jet ◽  
Time Behavior ◽  
Charge Coupled Device ◽  
Intensified Charge Coupled Device

The present work aims to investigate the interaction between a plasma jet and targets with different physical properties. Electrical, morphological and fluid-dynamic characterizations were performed on a plasma jet impinging on metal, dielectric and liquid substrates by means of Intensified Charge-Coupled Device (ICCD) and high-speed Schlieren imaging techniques. The results highlight how the light emission of the discharge, its time behavior and morphology, and the plasma-induced turbulence in the flow are affected by the nature of the target. Surprisingly, the liquid target induces the formation of turbulent fronts in the gas flow similar to the metal target, although the dissipated power in the former case is lower than in the latter. On the other hand, the propagation velocity of the turbulent front is independent of the target nature and it is affected only by the working gas flow rate.

On the theory of unification of seismic imaging techniques

2001 ◽  
Author(s):  
Herman Jaramillo ◽  
Uwe Albertin
Keyword(s):  
Seismic Imaging ◽  
Imaging Techniques

A Detailed and in Situ Assessment of the Snowpack Physical Properties in a Discontinuous Humid Boreal Forest

2021 ◽  
Author(s):  
Benjamin Bouchard ◽  
Daniel F. Nadeau ◽  
Florent Domine
Keyword(s):  
Physical Properties ◽  
Snow Cover ◽  
Boreal Forests ◽  
Snow Water Equivalent ◽  
Weather Forecasting ◽  
Large Fraction ◽  
Heat Fluxes ◽  
Homogeneous Layer ◽  
Eastern Canada ◽  
Snow Water

<p>Boreal forests occupy a large fraction of the continental surfaces and receive a lot of solid precipitation in winter. Evergreen canopies are often represented as a single and homogeneous layer in hydrological and weather forecasting models. However, in reality, boreal canopies are composed of a rather complex mosaic of trees unevenly spaced apart, with gaps of various sizes. Therefore, mass and energy inputs to the snowpack show remarkable variability at small scales resulting not only in strong spatial heterogeneity in snow depth (SD) and snow water equivalent (SWE), but also in the vertical temperature gradient in the snow column (<img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.8b7ab390ecff53808040161/sdaolpUECMynit/12UGE&app=m&a=0&c=763df4650e7419e8d52dae70af81e2ad&ct=x&pn=gnp.elif&d=1" alt="" width="48" height="17">). Unlike SD and SWE, <img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.8b7ab390ecff53808040161/sdaolpUECMynit/12UGE&app=m&a=0&c=763df4650e7419e8d52dae70af81e2ad&ct=x&pn=gnp.elif&d=1" alt="" width="48" height="17"> has been little documented in discontinuous needleleaf forests, despite its impact on snow cover metamorphism and on a range of physical properties of snow such as density (<img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.d6e05221ecff56228040161/sdaolpUECMynit/12UGE&app=m&a=0&c=e83ed3b230a37b46d23b9b7d13655568&ct=x&pn=gnp.elif&d=1" alt="" width="17" height="16">), specific surface area (SSA) and effective thermal conductivity (k<sub>eff</sub>). This work investigates the snowpack underneath the canopy and inside small forest gaps using continuous measurements of SD and k<sub>eff</sub> and weekly snow pit surveys during winter 2018-19 in a juvenile balsam fir stand of eastern Canada (47°17’18’’N, 71°10’05’’W). This site receives an average of almost 1600 mm of precipitation annually, including 40 % falling as snow. Snow cover typically lasts over 6 months. Observations show that less snow accumulates in the subcanopy and therefore <img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.8b7ab390ecff53808040161/sdaolpUECMynit/12UGE&app=m&a=0&c=763df4650e7419e8d52dae70af81e2ad&ct=x&pn=gnp.elif&d=1" alt="" width="46" height="16"> is more pronounced than inside the gaps. Moreover, <img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.d6e05221ecff56228040161/sdaolpUECMynit/12UGE&app=m&a=0&c=e83ed3b230a37b46d23b9b7d13655568&ct=x&pn=gnp.elif&d=1" alt="" width="17" height="16"> and SSA are lower underneath the canopy where faceted crystals are observed. Large <img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.8b7ab390ecff53808040161/sdaolpUECMynit/12UGE&app=m&a=0&c=763df4650e7419e8d52dae70af81e2ad&ct=x&pn=gnp.elif&d=1" alt="" width="49" height="17"> in that environment results in a decreasing k<sub>eff</sub> over time. Overall, kinetic grain growth takes place in the subcanopy whereas settlement and isothermal conditions prevail inside the gaps. This research provides accurate observations of the snowpack in forested environments needed for a better representation of SWE, heat fluxes and ground thermal regime in hydrological and meteorological models.</p>

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