A chlorine isotope transect across Sudbury Basin (Canada) impact deposits reveals systematic isotope fractionation
Bibliographic record
Abstract
Abstract Large-scale impacts are known to have a significant effect on volatile systematics (e.g., hydrogen and chlorine) owing to syn- and post-shock pressures and temperatures allowing for ready volatile loss and isotopic fractionation. We determined the Cl isotopic composition and [Cl] and [H2O] for apatite from 10 samples of the Sudbury impact structure in Canada. The high [Cl] and invariant δ37Cl values in the lower norite are attributed to footwall assimilation in agreement with recent Zn and Pb data. The granophyre, the top of the Sudbury Igneous Complex, displays loss and fractionation of Cl (up to +6.26‰) indicative of degassing under a high gas pressure regime with high [H2O] further buffering isotope fractionation. Similar impacts on dry, airless bodies such as the Moon may have permitted greater amounts of isotopic fractionation, supporting extremely fractionated lunar materials as evidence for the large-scale impact-derived degassing hypothesis. The modest fractionation (up to +8.15‰) and morphologically distinct apatite of the Onaping Formation can be explained by post-impact hydrothermal alteration.
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 | 0.000 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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; both teacher heads agree on what is shown here.
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".