Why are there no Cu-porphyry deposits in Jurassic Sanandaj-Sirjan zone intrusions of Iran?
Bibliographic record
Abstract
Granitoid intrusions of Zagros orogenic and metallogenic belt were mainly emplaced during the Jurassic-Cretaceous and Upper Eocene – Pliocene along the Sanandaj-Sirjan Zone (SaSZ) and Urumieh-Dokhtar magmatic Arc (UDMA), respectively. The present work tried to answer the question of whether or not there are fundamental differences in magmatic systems of Mesozoic versus Cenozoic intrusions of Zagros orogen resulting in the lack of porphyry mineralization in SaSZ compared with the widespread occurrence of porphyry-bearing intrusions in the UDMA. Characterizing the geochemical features of six major granitoid intrusions in the SaSZ (Alvand, Almogholagh, Aligoodarz, Boroujerd, Dehno, and Kolah-Ghazi) show they mostly represent low to high-K calc-alkaline and peraluminous magmatic suite, which is analogous to those reported previously for the UDMA porphyry Cu intrusions. However, the SaSZ intrusions are characterized by extremely low Sr/Y contents, distinct negative Eu anomalies, and less fractioned HREE patterns with OIB signature in the less fractionated samples indicating a source dominated by melting of subcontinental lithosphere mantle. This study proposed that the inception of Cenozoic flat slab subduction followed by dehydration melting of ~ 29 Ma of metasomatized subcontinental lithospheric mantle (SCLM) during the continuous stages of continental-continental collision has a decisive role in magmatic change to a more hydrous and oxidized nature. These processes provided unique conditions for increasing metal fertility of these Miocene intrusions compared to those of older Mesozoic igneous activities in the Zagros orogenic and associated metallogenic belt.
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 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 | 0.000 | 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 | 0.000 | 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) | 0.029 | 0.001 |
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".