Performance of low-fold scalar migration for downhole seismic imaging of massive sulfide ore deposits at Norman West, Sudbury, Canada

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC3-WC13 ◽  
Author(s):  
Christof Mueller ◽  
Gilles Bellefleur ◽  
Erick Adam ◽  
Gervais Perron ◽  
Marko Mah ◽  
...  
Keyword(s):  
Seismic Data ◽  
Seismic Imaging ◽  
Signal To Noise Ratio ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Ore Deposit ◽  
Seismic Scattering ◽  
Vertical Seismic Profiling ◽  
Sudbury Igneous Complex ◽  
Sulfide Ore

The Downhole Seismic Imaging consortium conducted two consecutive vertical seismic profiling surveys in the Norman West mining camp (Sudbury, Canada) in 1998 and 1999. These were aimed toward imaging a massive sulfide ore deposit situated within the footwall of the Sudbury Igneous Complex (SIC). Three-component seismic data were acquired in four boreholes with variable signal-to-noise ratio and poor polarization quality. Consequently, the images suffered from strong azimuthal ambiguity. A strike filter, passing only reflections originating from within the SIC, was applied during migration to enhance interpretability of the images obtained. Migrated images showed structures correlating with the known position of an ore deposit located 1800 m away from one borehole (N40). Diffraction coherency migration enhanced the image of the deposit, and suggested strong seismic scattering from within the footwall of the SIC.

Petrogenetic significance of chromian spinels from the Sudbury Ignecus Complex, Ontario, Canada

1997 ◽  
Vol 34 (10) ◽  
pp. 1405-1419 ◽  
Author(s):  
Mei-Fu Zhou ◽  
Reid R. Keays ◽  
Peter C. Lightfoot ◽  
Gordon G. Morrison ◽  
Michelle L. Moore
Keyword(s):  
Magma Mixing ◽  
Ore Deposits ◽  
Chromian Spinel ◽  
Triangular Diagram ◽  
Element Abundances ◽  
Sudbury Igneous Complex ◽  
Magmatic Sulfides ◽  
Sulfide Ore ◽  
Host Rocks ◽  
Chamber Floor

Chromian spinels occur in mafic–ultramafic inclusions in the Sublayer of the Sudbury Igneous Complex (SIC) as well as in mafic–ultramafic rocks in the immediate footwall of the Sublayer. The host rocks are pyroxenite and melanorite with minor dunite, harzburgite, and melatroctolite. As common accessory phases in these rocks, the chromian spinels display euhedral or subhedral forms and are included in olivine and orthopyroxene. Chromian spinel grains generally have ilmenite lamellae and contain abundant inclusions (zircon, olivine, diopside, plagioclase, biotite, and sulfide). All the chromian spinels have similar trace element abundances and are rich in TiO2 (0.5–15 wt.%). They have constant Cr# (100Cr/(Cr + Al)) (55–70) and exhibit a continuum in composition that traverses the normal fields of spinels in a Al–(Fe3+ + 2Ti)–Cr triangular diagram. This continuum extends to that of the composition of chromian magnetite in the host norite matrix to the mafic–ultramafic inclusions. This continuum in composition of the spinels suggests that the noritic matrix to the Sublayer formed from the same magma as the inclusions. A positive correlation between the Cr and Al contents of the spinels was probably produced by dilution of these elements by Fe3+ contributed, perhaps, by a plagioclase-saturated melt. Zircon inclusions in a chromian spinel grain reflect incorporation of crustal, felsic materials into the magma before crystallization of chromian spinel. The chemical characteristics and mineral inclusions of the spinels suggest that the Sublayer formed in response to magma mixing. It is suggested that subsequent to the formation of the crustal melt, mantle-derived high-Mg magmas mixed vigourously with this and generated the magmatic sulfides that eventually formed the Ni – Cu – platinum-group elements sulfide ore deposits. Some of the early crystallization products of the high-Mg magma settled to the chamber floor, where they partially mixed with the crustal melt and formed the mafic–ultramafic inclusions and footwall complexes.

Pyrite deformation textures in the massive sulfide ore deposits of the Norwegian Caledonides

2010 ◽  
Vol 483 (3-4) ◽  
pp. 269-286 ◽  
Author(s):  
Craig D. Barrie ◽  
Alan P. Boyle ◽  
Nigel J. Cook ◽  
David J. Prior
Keyword(s):  
Massive Sulfide ◽  
Ore Deposits ◽  
Sulfide Ore ◽  
Deformation Textures ◽  
Norwegian Caledonides

Rb-Sr isotope dating of silicalite from the Dajiangping massive sulfide ore deposit, Guangdong Province

1997 ◽  
Vol 42 (23) ◽  
pp. 1983-1985 ◽  
Author(s):  
Wang Henian ◽  
Li Hongyan ◽  
Wang Yingxi ◽  
Wang Haihong
Keyword(s):  
Guangdong Province ◽  
Massive Sulfide ◽  
Sr Isotope ◽  
Ore Deposit ◽  
Sulfide Ore ◽  
Isotope Dating

Delineating ophiolite-derived host rocks of massive sulfide Cu-Co-Zn deposits with 2D high-resolution seismic reflection data in Outokumpu, Finland

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC213-WC222 ◽  
Author(s):  
I. T. Kukkonen ◽  
S. Heinonen ◽  
P. Heikkinen ◽  
P. Sorjonen-Ward
Keyword(s):  
Seismic Data ◽  
Host Rock ◽  
Seismic Reflection ◽  
Massive Sulfide ◽  
High Amplitude ◽  
Ore Deposits ◽  
Acoustic Properties ◽  
Rock Properties ◽  
Seismic Reflection Data ◽  
Reflection Data

Seismic reflection data was applied to a study of the upper crustal structures in the Outokumpu mining and exploration area in eastern Finland. The Cu-Co-Zn sulfide ore deposits of the Outokumpu area are hosted by Palaeoproterozoic ophiolite-derived altered ultrabasic rocks (serpentinite, skarn rock, and quartz rock) and black schist within turbiditic mica schist. Mining in the Outokumpu area has produced a total of 36 Mt of ore from three historical and one active mine. Seismic data comprises 2D vibroseis data surveyed along a network of local roads. The seismic sections provide a comprehensive 3D view of the reflective structures. Acoustic rock properties from downhole logging and synthetic seismograms indicate that the strongly reflective packages shown in the seismic data can be identified as the host-rock environments of the deposits. Reflectors show excellent continuity along the structural grain of the ore belt, which allows correlating reflectors with surface geology, magnetic map, and drilling sections into a broad 3D model of the ore belt. Massive ores have acoustic properties that make them directly detectable with seismic reflection methods assuming the deposit size is sufficient for applied seismic wavelengths. The seismic data revealed numerous interesting high-amplitude reflectors within the interpreted host-rock suites potentially coinciding with sulfides.

A general solution for a spherical conductor in a magnetic dipole field

Geophysics ◽  
1979 ◽  
Vol 44 (4) ◽  
pp. 781-800 ◽  
Author(s):  
Melvyn E. Best ◽  
Basil R. Shammas
Keyword(s):  
Magnetic Dipole ◽  
Spherical Model ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Dipole Field ◽  
First Approximation ◽  
Sulfide Ore ◽  
Magnetic Dipole Field ◽  
Airborne Em ◽  
Spherical Conductor

In electromagnetic (EM) prospecting for volcanogenic massive sulfide ore deposits, a significant number of the responses are associated with compact conductors. As a first approximation, these bodies are studied using a conducting sphere model. An exact solution is given for a spherical conductor excited by a magnetic dipole field in free space for arbitrary transmitter‐receiver (T-R) configurations with receiver positions inside or outside the conductor. In this general approach, it is possible to investigate the lateral attenuation of EM systems. In particular, the effects of flight‐line displacement from the center of the spherical conductor on several airborne EM responses are presented. For example, at normal flying heights, the standard Dighem system has a lateral attenuation 50 times larger than the EM-30 system (for a sphere of 100 m radius). Field results from the Clearwater deposit in New Brunswick are compared to the spherical model attenuations for the Dighem, Otter, and F-500 systems. The behavior of the total magnetic fields [Formula: see text] and [Formula: see text] inside the conductor are presented in the form of magnitude and phase contours. The [Formula: see text] amplitude was found to be approximately the same inside and outside the sphere; the [Formula: see text] amplitude, however, differs significantly in these two regions. Observations such as these may provide some guidance in subdividing anomalous inhomogeneities in future numerical modeling.

Hydrothermal models for the generation of massive sulfide ore deposits

1985 ◽  
Vol 90 (B10) ◽  
pp. 8769-8783 ◽  
Author(s):  
Robert P. Lowell ◽  
Peter A. Rona
Keyword(s):  
Massive Sulfide ◽  
Ore Deposits ◽  
Sulfide Ore

The formation of the volcanic-hosted massive sulfide ore deposit at Rosebery, Tasmania

1981 ◽  
Vol 76 (2) ◽  
pp. 304-338 ◽  
Author(s):  
G. R. Green ◽  
M. Solomon ◽  
J. L. Walshe
Keyword(s):  
Massive Sulfide ◽  
Ore Deposit ◽  
Sulfide Ore
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