An analytical protocol for determining the elemental chemistry of Quaternary sediments using a portable X-ray fluorescence spectrometer
Bibliographic record
Abstract
The modern geologist has a plethora of portable digital tools at their disposal including, GPS, in-field computers providing access to imagery, maps, and on site real time geochemistry provided by portable X-ray fluorescence spectrometry (pXRF). This paper presents an analytical protocol for the examination of Quaternary glaciogenic sediments derived from different bedrock terrains using a portable spectrometer. The protocol outlines best practices for the collection of geochemical data using pXRF from glacoiogenic sediments with generally continental crustal abundance elemental concentrations at a fraction of the cost of traditional laboratory methods. The analytical protocol considers 1) sample preparation, 2) sample analysis, and 3) data cleaning, examination and presentation. The protocol takes into consideration pXRF fundamentals related to, instrument configuration, and an assessment of measurement parameters, including peak overlaps, dwell time, instrument drift, in-situ versus processed samples, variable grain size and moisture content effects, and comparison to traditional laboratory methods. Protocol development occurred over a number of years and analysis of over 4000 geological samples and ~9000 analysis of Certified and Standard Reference Materials.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.015 | 0.009 |
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".