REE Geochemistry of the Uranium Phases in Syn-Magmatic and Hydrothermal-Type U-Mineralisation: Two Case Histories from India
Bibliographic record
Abstract
Abstract Rare Earth Elements (REE) geochemistry of uranium-bearing phases from two genetically different types of uranium mineralisation is presented here. These include the syn-magmatic type, hosted by part of the Suryamalai or Sankari granite in the Kullampatti area, Tamil Nadu and hydrothermal vein type, hosted by both basement granitoid and its overlying Shahabad Limestone in the Bhima basin at Gogi, Karnataka. The study is based on the Electron Microprobe (EMP) analysis of selected REEs from different U-bearing phases, viz., uraninite, its pseudomorphic altered product of gummite, pitchblende and coffinite. Those hosted by granite, compared to that in limestone, have higher contents of XREE. Those in syn-magmatic type contain HREE >LREE and vice-versa in hydrothermal type. The former pattern is reflected in the co-existing Y- and HREE-bearing multiple oxides of fergusonite, samarskite and betafite. Furthermore, U-bearing organic matter and smectite-illite clay at Gogi contain higher contents of LREE. Pitchblende in both granite and limestone shows perceptible positive Ce-anomaly whereas the coffinite in limestone shows negative Ce-anomaly. In the plot of EREE vs. chondrite-normalised LREE/HREE, except for those in the granite-hosted syn-magmatic type, the rest of U-phases as well as uraninite from other types (taken from literature) define a trend of positive correlation. The minimum-end of the ZREE is represented by the unconformity-type of Collins Bay, Canada and Pine Creek deposits, Australia, and the maximum-end of SREE by hydrothermal vein type in the granite at Gogi. The syn-magmatic granite-hosted uraninite from Kullampatti, Rossing and Faraday plot close to each other, but away from the main positive trend toward a higher EREE. In simple oxides of uranium, LREE, MREE and HREE, appear to co-exist or substitute, respectively, for Ca, Th and U, as indicated by the corresponding increasing trends. During post-magmatic alteration of uraninite to gummite and samarskite to betafite, there is a notable depletion of especially the HREE. During coffinitisation of pitchblende or replacement of coffinite by pitchblende, there is a similar depletion, especially the LREE in the former and the MREE in the latter.
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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 | 0.000 | 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 | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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 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".