Natural Allanite Reference Materials for<i>In Situ</i>U‐Th‐Pb and Sm‐Nd Isotopic Measurements by LA‐(MC)‐ICP‐MS
Bibliographic record
Abstract
Allanite is a common accessory mineral that generally incorporates considerable amounts of Th, U and light rare Earth elements in its structure, making it a useful mineral for in situ U‐Th‐Pb geochronology and Sm‐Nd isotope measurements. Here, we present in situ U‐Th‐Pb ages and Sm‐Nd isotopic compositions for nine allanite samples considered as potential reference materials (CAP b , Tara, Daibosatsu, LE40010, LE2808, A007, A011, A012 and SQ‐51), with ages ranging from ~ 2650 Ma to ~ 12 Ma. Our study indicates that Daibosatsu and LE40010 have relatively homogeneous 147 Sm/ 144 Nd and 143 Nd/ 144 Nd isotopic compositions ( 147 Sm/ 144 Nd ratio variation is less than 2%) and, thus, can serve as primary reference materials for Sm‐Nd microanalysis. In contrast, CAP b , Tara, LE2808, A007, A011 and A012 all show homogeneous calculated initial 143 Nd/ 144 Nd isotopic compositions, but with variable 147 Sm/ 144 Nd compositions, and thus can be used only as secondary reference materials for Sm‐Nd microanalysis. Of these materials, LE40010 allanite can serve as a suitable primary reference material for in situ U‐Pb dating, CAP b allanite can serve as a suitable primary reference material for in situ Th‐Pb dating, and LE2808, LE40010, A007, A011 and A012 can serve as suitable secondary reference materials for in situ U‐Pb geochronology. In addition, Daibosatsu is suitable as a secondary reference material for Cenozoic Th‐Pb dating to monitor data reproducibility.
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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 | 0.004 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".