Geochemical,Sr-Nd isotope,and zircon U-Pb geochronological constraints on the origin of Early Cretaceous carbonatite dykes,northern Shanxi Province,China
Bibliographic record
Abstract
Carbonatite dyke swarms are widespread across the North China Craton( NCC) in Shanxi Province. Here,we present new geochemical,Sr-Nd isotope,and U-Pb zircon age data for representative samples of the dykes. Laser ablation-inductively coupled plasma-mass spectrometry( LA-ICP-MS) U-Pb analyses yielded a Cretaceous age of 132. 9 ± 0. 6Ma for zircons extracted from one dyke. Whole rock K-Ar ages for three samples range from 131. 3Ma to 132. 6Ma. The carbonatites have highly uniform major element compositions and are enriched in light rare earth elements and large ion lithophile elements( LILEs; e. g.,Ba,U,Pb,and Sr),and depleted in K and high field strength elements( HFSEs; e. g.,Ta,P,and Ti). The carbonatite dykes have relatively uniform(87Sr / 86Sr) i values that range from 0. 7079 to 0. 7083,and negative values of e Nd( t)(-16. 7 to-15. 2). These data suggest that the dyke magmas were derived from the partial melting of an enriched region of the lower lithospheric mantle,with evident crustal contamination. The carbonatite dykes within the northern NCC formed during the mixing of the continental crust with sub-continental lithospheric mantle.
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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 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".