Melting of Subducted Continental Crust in the Cimmerian Collisional Orogenic Belt, NE Iran
Bibliographic record
Abstract
Abstract The subduction of continental crust in orogenic belts that are not associated with high-pressure metamorphism is still poorly understood. The Late Triassic postcollisional granitic rocks of NE Iran are related to the convergence between the Central Iran terrane and the Turan terrane on the southern margin of the Eurasian continent. They intruded into the Paleo-Tethyan suture between the Central Iran and Turan terranes. Granitoids of the Torbat-e-Jam pluton were emplaced at ca. 217 Ma, and their moderately high SiO2 (>64 wt. %), low MgO contents (mostly <2 wt. %), slightly depleted Sr-Nd, and zircon Hf isotopes suggest partial melting of a juvenile crust. Granodiorites from NW and SE Mashhad were emplaced at ca. 217 and 200 Ma, and their geochemical features and enriched Sr-Nd and zircon Hf isotopes suggest melting of continental crust. Inherited zircon cores in both the NW and SE Mashhad intrusions have dominant age peaks of ca. 540 and 770 Ma, similar to the age spectrum of adjacent Paleozoic sediments derived from the Central Iran terrane, but distinct from Triassic sediments sourced from the Turan terrane. The inherited zircon cores cannot be explained by crustal contamination during magma ascent, rather the age pattern of inherited zircon cores coincides with major magmatic events in the Central Iran terrane and fingerprint their source, suggesting partial melting of the subducted Central Iran continental crust. This study suggests that the melting of subducted continental crust can occur in simple collisional belts, rather than being confined to ultrahigh-pressure metamorphic orogenic belts.
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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 | 0.001 |
| Science and technology studies | 0.000 | 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".