STRUCTURAL GEOLOGY, STRATIGRAPHY AND PETROLOGY OF THE ELKHORN RIDGE ARGILLITE, IN THE SUMPTER AREA, NORTHEASTERN OREGON
Bibliographic record
Abstract
The Elkhorn Ridge Argillite exposed in the Bourne-Sumpter area of eastern Oregon is a broken formation of metamorphosed (greenschist facies) hemipelagic sediments, reefal carbonates, rare clastics, mafic volcanics and intrusives that may have accumulated in a late Triassic-Early Jurassic subduction zone complex or marginal basin. The structural fabric of this unit is best explained by a model of repeated homoaxial folding and simple and/or pure shear during progressive deformation. Deformation began before the sediments were completely lithified and tight to isoclinal mesoscopic folds developed with and without axial-plane cleavage. A predominant spaced cleavage formed by a combination of dissolution-redeposition processes and microfaulting. Grain boundary sliding and movement along microfaults are important additional deformation mechanisms that operated during flexural slip folding. The lithology and structural style of the Elkhorn Ridge Argillite are characteristic of deformed sequences in subduction zone complexes and marginal basins and can not be used to discriminate paleotectonic settings. New faunal evidence suggests that substantial disruption of structural stratigraphic units such as the Elkhorn Ridge Argillite have taken place during the Late Triassic to late Jurassic. Coeval blocks of similar lithology and fauna are located in the Miller Mountain area within the John Day inlier of central Oregon and in several terranes distributed along the western Cordillera from California to Canada. Other blocks of oceanic lithic assemblages of various ages in intermediate areas show significant differences in structural and sedimentological history and together are interpreted to lie within a diffuse fault zone of amalgamated suspect terranes.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".