In suspect terrane? Provenance of the late Archean Phantom Lake metamorphic suite, Sierra Madre, Wyoming
Bibliographic record
Abstract
The 2.68 Ga Phantom Lake metamorphic suite of the Sierra Madre is a volcanogenic, volcaniclastic, and siliciclastic sequence that may have been deposited on or near the margin of the Wyoming Province or, alternatively, it may represent part of an exotic block accreted onto the southern margin of the Wyoming Province. The metamorphosed supracrustal rocks of the Phantom Lake metamorphic suite, along with quartzofeldspathic gneisses and granitoids of similar age, have light rare-earth element (LREE) – enriched REE patterns with little to no Eu-anomaly. These patterns are comparable to those of modern oceanic arc rocks and sediments. Both supracrustal and metaigneous rocks have radiogenic initial εNd from +4.5 to –2.5 and Nd crustal residence ages between 2.7 and 3.0 Ga. It is proposed that these juvenile rocks were part of an intra-oceanic arc system formed beyond the influence of detritus from the Wyoming Province and subsequently were accreted onto the southern Wyoming Province following intrusion of granitic gneisses in the Sierra Madre at ca. 2.64 Ga. The younger 2.43 Ga Baggot Rocks granite has less radiogenic εNd of –3.9 suggesting that the rocks of the Sierra Madre had accreted to the Wyoming Province by 2.43 Ga. The supracrustal sequences at South Pass, Bradley Peak, and the Rattlesnake Hills have similar, radiogenic initial Nd isotope compositions. Together with the Phantom Lake metamorphic suite, they represent juvenile additions to existing continental crust and provide evidence that lateral accretion of oceanic terranes was an important process of late Archean crustal growth in the Wyoming Province.
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 | 0.000 | 0.001 |
| 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".