Physical rock properties from the Athabasca Group: designing geophysical exploration models for unconformity uranium deposits

Mwenifumbo, C J; Elliott, Beverley; Jefferson, C W; Bernius, G R; Pflug, K A

doi:10.1016/j.jappgeo.2003.06.008

Cited by 34 publications

(18 citation statements)

References 2 publications

(2 reference statements)

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“…This is in agreement with the log data from the borehole CX-61, showing an average velocity varying from approximately 3800 m∕s near the surface to 4400 m∕s above the unconformity ( Figure 10). The stacking velocity is also within the range of measured velocities for sandstones in the western Athabasca Basin, but significantly lower than velocities (4500-1600 m∕s) for sandstones in the McArthur River area (Mwenifumbo et al, 2004). Velocity models from regional seismic profiles in the McArthur River area show velocities in rough agreement with our stacking velocity.…”

Section: Data Processingsupporting

confidence: 81%

3D seismic survey at the Millennium uranium deposit, Saskatchewan, Canada: Mapping depth to basement and imaging post-Athabasca structure near the orebody

et al. 2012

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Three-dimensional seismic reflection measurements have been used to assist mine planning at the Millennium uranium deposit, Canada. The deposit is located within the crystalline basement, separated from the overlying Athabasca Basin sediments by an unconformity potentially associated with significant fluid flow. The primary objective of the ∼6.5 km 2 survey was to image the unconformity and possible post-Athabasca deformation structures in and around the deposit. Clear unconformity reflections are observed within most of the survey area, although there are amplitude variations due to complex geology, including intense hydrothermal clay alteration around the deposit. Finite-difference modeling indicates that the wideangle character of the unconformity reflections is due to a gradual velocity increase at the unconformity. The reflections are obscured by large time delays, due to Quaternary sediments covering the area, making refraction static corrections crucial.The seismic interpretation shows large variations in the unconformity depth (from approximately 430 to 650 m), indicating a pronounced basement depression that coincides with a gravity low. Reflections from the unconformity are vague within the depression, especially in the vicinity of the deposit. Although the orebody is not directly visible in the seismic image, there is a lack of reflectivity coincident with the alteration surrounding the mineralization. We also observed reflections which likely originate at the contact between the altered and fresh basement rock located beneath the deposit. The seismic data further indicate post-Athabasca faults in the vicinity of the orebody. Based on the initial seismic interpretation, the depth of the crown pillar was adjusted and the mine infrastructure moved away from areas interpreted to be affected by the intense hydrothermal alteration surrounding the deposit. The capability to image the unconformity, post-Athabasca structure, and hydrothermal alteration also highlights the potential use of seismic surveys in uranium exploration.

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Section: Data Processingsupporting

confidence: 81%

3D seismic survey at the Millennium uranium deposit, Saskatchewan, Canada: Mapping depth to basement and imaging post-Athabasca structure near the orebody

et al. 2012

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“…Coincidentally, Mwenifumbo et al . () also documented significant changes for in situ density, V P velocity, and acoustic impedance of the MF Read Formation, which extends throughout the basin. These changes also correlate significantly with comparable resistivity variations.…”

Section: Acoustic Properties – Mineralization Indicatorsmentioning

confidence: 88%

“…From well log data investigations in the Shea Creek area, Mwenifumbo et al . () provided some specifics about the Athabasca Group physical properties from the western part of the basin.…”

Section: Acoustic Properties – Mineralization Indicatorsmentioning

confidence: 99%

Uranium mineralization indicators from seismic and well log data in the Shea Creek area at the southern margin of the Carswell impact structure, Athabasca Basin, Canada

Hajnal

Takács

Pandit

et al. 2015

Geophysical Prospecting

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A B S T R A C TThe primary economic uranium (U) mineralization indicators in the Athabasca Basin are the reactivated prominent basement deformation zones, basement alteration halos, and the overlying sandstone alteration halos enveloping the deposit. High-resolution seismic surveys, from the Shea Creek area, are investigated to assess the potential of the surface seismic reflection technique for detecting these key mineralization markers. Four seismic profiles identify ductile to highly brittle deformation features of the basement. One of the brittle deformation features is a southwest-dipping prominent reactivated shear zone comparable to basement structures hosting other known deposits in the basin. The Carswell meteor impact structure is also a conspicuous component of the Shea Creek regional structural regime. The seismic sections identify several features of the impact structure, including recognition that the dimensions of this structure are significantly larger than those estimated by previous geological studies. This larger area includes both the Cluff Lake mine and the Shea Creek U deposits, and it reveals that the basement was considerably disturbed by the impact and suggests the reactivation of the southwest-dipping shear zone. Complex trace analysis of the seismic sections provides detailed information about the lateral changes in the reflectivity properties of the unconformity interval, which is another key zone of interest for uranium exploration. Based mainly on velocity information, several sub-zones of clay alteration and silicification were identified within prominent fracture depth intervals: both in the sandstone and the basement. Thus, this study documents that these primary mineral indicators can be detected by the seismic method. Cross-plots of velocity versus density of well log data identify changes in lithological units such as unaltered basement, fractured/altered basement, unaltered sandstone, clay alterations in sandstone, and silicification in sandstone.

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“…However some advanced research as study of multi-parameter (resistivity, density, porosity, velocity) borehole geophysical measurement is necessary [20] to know the physical rock property data in the target A1 and B1.…”

Section: Maps International Journal Of Geosciencesmentioning

confidence: 99%

Integrated Interpretation of Geophysical and Soil Geochemical Anomalies in Gold Exploration: Case of Kouremale, Southern Mali-West Africa

Tounkara¹,

Chen²,

Keita³

2017

IJG

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Detecting the anomalies' sources location in the vast territory such as Kouremale area is a grand challenge for geophysicists because there is a need to assess gold deposit. Therefore, this paper aims to recommend a methodological approach on applied magnetic survey and soil geochemistry to identify the location of anomalies' sources. To that aim the study is divided into phases. In the first phase, the maps for integrated interpretation have been produced by Geosoft Oasis and ArcGIS 10.2.1. The corrected and processed magnetic data with eliminated diurnal variation have been used. Phase two consist of integrate geochemical soil map. The results of phase one identified four magnetic anomalies zones (MAZ) with their coordinates. Thus, the obtained radiometric map, showed that there is a high intensity of K and Th compared to U, which indicates a significant weathering process and there are many saprolithes in study area. The findings of phase two revealed that there is a high concentration of gold content (1500 ppm) with an average concentration of 92 ppm. The integrated interpretation map coming from the combined different maps, referring to the geological information verified on the field, led to conclude that, the target B is the best gold anomaly. The delimitation of the space of the target B from the geophysical and geochemical information confirmed the existence of limited, restricted and potential anomaly.

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Physical rock properties from the Athabasca Group: designing geophysical exploration models for unconformity uranium deposits

Cited by 34 publications

References 2 publications

3D seismic survey at the Millennium uranium deposit, Saskatchewan, Canada: Mapping depth to basement and imaging post-Athabasca structure near the orebody

3D seismic survey at the Millennium uranium deposit, Saskatchewan, Canada: Mapping depth to basement and imaging post-Athabasca structure near the orebody

Uranium mineralization indicators from seismic and well log data in the Shea Creek area at the southern margin of the Carswell impact structure, Athabasca Basin, Canada

Integrated Interpretation of Geophysical and Soil Geochemical Anomalies in Gold Exploration: Case of Kouremale, Southern Mali-West Africa

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