Tectonomagmatic implications and ages of caribbean island-arc tholeiites, boninites and related felsic rocks, Cordillera Oriental, Dominican Republic
Bibliographic record
Abstract
Located in the Cordillera Oriental of the Dominican Republic, the Early Cretaceous Los Ranchos Fm comprises a thick sequence of volcanic and volcaniclastic rocks with variable geochemical characteristics, which is intruded by tonalite batholiths, minor gabbro/diorite plutons and mafic dykes. From top to bottom, three main stratigraphic units have been mapped: upper basaltic, intermediate rhyodacitic and lower basaltic. Combined detailed mapping, stratigraphy, geochemistry, Rb-Sr/Sm-Nd isotopic studies and U-Pb/Ar-Ar geochronology have shown that mafic rocks of the Los Ranchos Fm include boninites (group III) and LREE-depleted tholeiitic island arc basalts (group II) in the lower unit, which are interpreted to be genetically related, and normal island arc tholeiites (group I) in the upper unit. The source for these rocks was variably depleted mantle, overprinted by a subduction zone component. Contemporaneous Aptian U-Pb zircon ages of rhyodacite from the intermediate unit (116.0±0.8 Ma) and tonalite from Zambrana batholith (115.5±0.3 Ma), with equivalent trace-element geochemical characteristics, argue for a genetic link between felsic volcanic rocks of the Los Ranchos Fm and the voluminous tonalite magmatism that intrude their lower stratigraphic levels. Low-K rhyolites and tonalite batholiths are interpreted as products of secondary melting at the base of thickened early arc crust. 40Ar/39Ar plateau ages of hornblende in four tonalite batholiths are Albian (109-106 Ma) and interpreted as recording the final cooling after emplacement, previously to the Albian sedimentation of uncomformably reef limestones of the Hatillo Fm. In this context, LREE-depleted IAT and boninites of lower basaltic unit formed during subduction zone initiation, and the normal IAT of the upper unit represent the posterior stabilization of the volcanic front.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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".