The Coronitic Perchatka Layered Intrusion, Central Lapland–Belomorian Belt, Kola Peninsula, Russia
Bibliographic record
Abstract
Abstract The Paleoproterozoic Perchatka intrusion, located in the central Lapland–Belomorian Belt of the Fennoscandian Shield in the Kola Peninsula of Russia, displays clear patterns of modal and cryptic layering. Several megacyclic units led to the Peridotite Core (PC) at the base, the Intermediate Zone (IZ), the Cryptically Layered Zone (LZ), and the Gabbroic Zone (GZ) at the top. The ultrabasic rocks provide notable examples of various coronitic associations. In the earliest corona to form, olivine or magnesian clinopyroxene is deposited from a primitive melt around a chromite core. The most common type of corona is composite, with orthopyroxene overgrowing olivine, followed by an outer rim composed of a calcic amphibole or a mica of the phlogopite–annite series. The amphibole, a Na-K-Ti-Al-enriched pargasite or edenite, likely formed from an evolved interstitial melt. Similar compositions of amphibole, phlogopite, and magnesian orthopyroxene are recorded in a melt inclusion hosted by olivine. The existence of coronas at Perchatka results from a confluence of factors: (1) A thermal quench leading to rapid crystallization accompanied the hypabyssal emplacement of the complex. (2) Efficient differentiation led to a buildup in Al, Ca, Na, K, Ti, along with H2O, Cl, and F in residual portions of melt. (3) Relative abundances of intrinsic volatiles, especially H2O, caused an exsolution early in the crystallization history, giving rise to the hydrous silicates in the outer rim. (4) Subsolidus reactions with plagioclase played a subordinate role in the increase of Na and Al in the outer rim.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".