Upper Devonian and Lower Mississippian stratigraphy of Northwestern Montana: a petroleum system approach
Bibliographic record
Abstract
The Upper Devonian and Lower Mississippian stratigraphy in the Antler foreland basin of northwestern Montana is the current focus of exploration for several petroleum companies.Conodont zonation indicates that the Exshaw Formation of southern Alberta and northern Montana is Late Devonian and Early Mississippian in age, and is stratigraphically equivalent to the Bakken Formation in the Williston Basin and the Sappington Member of the Three Forks in southwestern Montana.The Exshaw, Bakken and Sappington are lithologically similar.Each formation is comprised of basal organic-rich shale, middle dolomitic siltstone and sandstone, and upper organic-rich shale.The Three Forks Formation in northwestern Montana consists of two members: the older Logan Gulch Member and the younger Trident Member.The Logan Gulch is 100 ft to over 450 ft thick and was subdivided in this study into three facies that were deposited in salina to sabkha environments.Locally, the Logan Gulch is termed the Potlatch Anhydrite.The Three Forks Formation in northwestern Montana is equivalent to the Stettler and Big Valley formations in southern Alberta.The younger Trident Member was subdivided into two facies that are transgressive, open marine deposits.The Trident is absent to over 100 ft thick, and is largely comprised of open marine, fossiliferous shale.The Exshaw Formation in the study area consists of three members: an upper shale, middle siltstone unit, and a lower shale.The upper and lower shales are black, organic-rich, and siliceous.The lower shale ranges from one ft to over 20 ft thick, while the upper shale is absent to approximately 12 ft thick.In portions of the study area, a detrital siltstone and very fine-grained sandstone member of the Banff Formation (Lower Lodgepole) conformably overlies the upper shale.The middle siltstone was deposited along a shallow
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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 | 0.003 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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 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".