Late Laramide dolomite recrystallization of the Husky Rainbow "A" hydrocarbon Devonian reservoir, northwestern Alberta, Canada: paleomagnetic and geochemical evidence
Bibliographic record
Abstract
The Rainbow Field is in reefal carbonates of the Middle Devonian Keg River Formation in the Western Canada Sedimentary Basin. Alternating field and thermal step demagnetization was done on specimens from unoriented core from a vertical, an inclined, and a horizontal well core in the dolomite reservoir. Although they had no viscous remanent magnetization component to use for orientation, most specimens had a well-defined characteristic remanent magnetization (ChRM) that resides in single to pseudosingle domain magnetite. By rotating the mean ChRM direction around its core axis, a small circle can be generated for each core and the small circles intersect in the true ChRM direction of D = 168°, I = -73.5 o (α 95 = 5.8°, k = 32.2). Its paleopole of 164°E, 83°N (A 95 = 10°) defines a Tertiary age with one sigma limits of Middle Eocene to Middle Miocene age. Petrographic examination defines four generations of dolomite. Matrix dolomite has 60-100 µm diameter crystals that were later recrystallized to 200-400 µm. Dolomite cements are represented by vug-filling coarse dolomite (100-200 µm) and saddle dolomite (1000 µm). All four generations of dolomite give similar δ 18 O values of -10.7 to -16.5 (Peedee Belemnite, PDB), δ 13 C values of +0.7 to +3.2 (PDB), and Sr isotopic ratios of 0.70826 to 0.70846 that do not match the expected Middle Devonian carbonate or seawater values. We interpret these data to indicate that mixed pre-Laramide basinal fluids, heated by burial during the Laramide Orogeny, were present during late Laramide time when the dolomites were recrystallized and (or) precipitated prior to petroleum migration and accumulation in the Rainbow "A" reservoir. Thus the combined use of paleomagnetism, geochemistry, and petrography has been proven to be a useful technique to date and identify dolomitization events and pathways for the migration of hydrocarbons.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".