Regional Seismic Images Beneath the McArthur River Ore Bodies, Saskatchewan
Bibliographic record
Abstract
Two subparallel, regional seismic reflection profiles of the multidisciplinary and multi-institutional EXTECH IV project outline fundamental relationships between the local structures of the McArthur River uranium mine of the Mesoproterozoic Athabasca Basin and the underlying deep crustal tectonic framework. This deep reflection sounding investigation crosses over the P2 ore body, which is located in the region of a magnetic low. Tomographic inversion of the first-break arrival times indicated lateral changes in P-wave velocities of the sandstone along the survey lines. Distinct high-velocity zones mark alteration of the sandstone over known mineralized zones in the P2 ore body. The migrated time sections are characterized by robust reflection signals from near surface to past-Moho depths. The sandstone-basement unconformity is clearly imaged, however, its correlation is more difficult along the central and southern part of the profiles due to influences of major structural disturbances. The differing patterns of reflections observed along the profiles will potentially allow distinction of the Wollaston/Mudjatik Transition Zone from the Wollaston Domain. South dipping reflections are traceable to a 4 km depth in the crust and are correlated with the P2 reverse fault that hosts the P2 ore bodies of the McArthur mine. The P2 structure is over 2.5 km thick and its seismic signature suggests multi-phase deformation. Strong, arcuate, and in places subparallel, zones of reflectivity dominate the middle and lower crust. The origin of these prominent seismic events appears to be located at the southern margin of the seismic investigation. Highly prominent, bright and sub-horizontal reflections, at 2.3 s two-way time (TWT), are the most distinct seismic signatures on the sections. These events are directly comparable to reflections observed along the northern half of the 1994 LITHOPROBE regional line S2B. The origin of this enigmatic zone of reflectivity is still under considerable discussion; this zone in 1994 data has been associated with the post-Hudsonian Mackenzie Igneous Event (1.265 Ga). The Moho is well defined at about 10.5 s TWT and is characterized by a number of laterally recognizable gently south-dipping reflections. Below the Moho, a zone of strong reflectivity delineates the upper mantle, revealing considerable tectonic involvement of the lithospheric mantle within the depth range of 35 to 45 km. A gentle southeastern dip in the tectonic development of the region symbolizes the overall structural attitude of this highly reflective zone.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.008 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".