ASSESSING HYDROTHERMAL ALTERATION INTENSITY IN VOLCANIC-HOSTED MASSIVE SULFIDE SYSTEMS USING PORTABLE X-RAY FLUORESCENCE ANALYSIS OF DRILL CORE: AN EXAMPLE FROM MYRA FALLS, CANADA
Bibliographic record
Abstract
Abstract Current portable X-ray fluorescence (pXRF) technology can rapidly and inexpensively yield concentrations of geologically significant elements, typically with instrument detection limits below several tens of parts per million. Based on conventional XRF whole-rock geochemical data, both the Ishikawa alteration index and the chlorite-carbonate-pyrite index increase with proximity to sulfide mineralization at Myra Falls. However, available pXRF technology is typically unable to detect all the elements required to calculate these alteration indices. As a result, there is a need to utilize the elements that are readily detectable using pXRF and apply these to hydrothermal alteration assessment. We propose that Rb/Sr ratios provide a robust proxy for the Ishikawa alteration index and demonstrate that conventional whole-rock XRF analytical results for Rb and Sr can be reproduced using pXRF analysis from drill core surfaces. At Myra Falls, the Rb/Sr ratios vary from <0.1 for least altered rocks, 0.1 to 0.5 for weakly altered rocks, 0.5 to 1.0 for moderately altered rocks, 1.0 to 2.0 for strongly altered rocks, and >2.0 for intensely altered rocks. Downhole profiles of alteration intensity generated from systematic pXRF analysis of drill core surfaces can be used to inform drilling and targeting decisions. The application of the Rb/Sr ratio as a proxy for alteration intensity extends beyond this case study and can be applied to other hydrothermal systems that produce phyllosilicate minerals as alteration products of feldspar.
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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 | 0.000 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".