Strain Signatures of Fjord Sediment Sliding: Micro-Scale Examples from Yakutat Bay and Glacier Bay, Alaska, U.S.A.
Bibliographic record
Abstract
Abstract Samples of gravity cores recovered from Yakutat Bay and Glacier Bay in southeast Alaska were examined in thin section. The samples, representing rhythmically laminated plume deposits, current-derived silts and sands, and iceberg-rafted diamicts, exhibit microstructures indicative of vertical deformation such as loading and water escape, as well as boudinage and other features, which are indicative of simple shear deformation. Narrow zones in many of the fine-grained core intervals show subtle patterns of preferred clay-mineral orientations (plasmic fabrics). We interpret these intervals as being low-strain simple shear zones. They all show a consistent and regular internal configuration that is formed by sets of conjugate shear planes. The setting and conditions in the Alaskan fjords allow the assumption that the shear zones are exclusively associated with penecontemporaneous movements of the unconsolidated sediment on subaqueous slopes. Analyzing characteristics and trends relating to symmetry and strain intensity, we argue that these are diagnostic identifiers for sliding mass movements. We present a conceptual model in which deformation resulting from gravity-driven sliding is described. We suggest that strain signatures can be used to recognize types of shear zones and be helpful in distinguishing between, for example, gravity-driven deformation and subglacial deformation in sedimentary records.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".