Origin of the Sokoman Iron Formation, Labrador Trough, Canada
Bibliographic record
Abstract
ABSTRACT The Lower Proterozoic, Lake Superior-type Sokoman Iron Formation of the Labrador Trough is one of the world's largest iron formations. It represents a unique, major event in the history of the Trough. Originally a largely irregularly bedded, intraclastic, granular, locally oolitic, conglomeratic iron formation, it is highly variable in its stratigraphy, mineralogy, and textures, which are the consequence of sedimentology, diagenesis, metamorphism, structural deformation, and magmatic overprint. Despite its complexity, the regional characteristics of the iron formation within the 1200 km length of the Labrador Trough indicate three main stratigraphic units, defined by their dominant iron minerals: the lower and upper parts of the formation are characterized by the abundance of iron silicates and carbonates (silicate-carbonate facies), and the middle part is characterized by the dominance of iron oxides (oxide facies). The origin of these lithostratigraphic units of the iron formation is attributed to three main sea-level changes which changed the chemistry (oxidation–reduction potential) and the physical energy (wave and current action) of the sedimentary environment. The vast amount of iron and some of the silica required for deposition of the Sokoman Formation is inferred to be the consequence of intense hydrothermal activity within a major rift created by the eastward extension of the Labrador Trough ca 1.88 Ga. The hydrothermal fluids venting within the rift saturated the deep and likely anoxic sea of the Trough with ferrous iron and some silica which then upwelled onto its oxygenated shallow waters to deposit the iron formation. The end of the processes involved in creating the iron formation ca. 1.82 Ga is attributed to the westward contraction of the Trough induced by the Hudsonian (Trans-Hudson) orogeny, which closed the iron- and silica-generating rift and at the same time ended all magmatic activities and related sedimentation coeval with the deposition of the iron formation.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".