Quartz Flow Law Revisited: The Significance of Pressure Dependence of the Activation Enthalpy
Bibliographic record
Abstract
Abstract An accurate flow law for dislocation creep of quartz aggregates is critical for the understanding of continental rheology, numerical modeling of lithospheric processes, and the interpretation of microstructures of natural quartz‐bearing mylonites. Despite many decades of research, considerable discrepancies still exist among quartz flow laws determined from different experiments. We demonstrate that the key to reconcile these discrepancies is to consider the pressure dependence of the activation enthalpy. From existing high‐quality creep experiments on quartz aggregates, we critically identified test runs having microstructures and stress‐strain curves indicating steady state regimes 2 and 3 dislocation creep and used the data to obtain a set of flow law parameters most consistent among existing experiments. Because estimates of strain rate and stress from natural mylonites are bound with large uncertainties, they cannot be used to construct a flow law better than one determined from well‐controlled creep experiments. A large number of geological studies and modern GPS observations suggest that crustal scale ductile shear zones likely flow at a strain rate range between 10 −13 and 10 −11 s −1 . In this strain rate range, our flow law predicts flow stresses broadly consistent with stress estimates from many natural mylonites based on well‐calibrated piezometers for dynamically recrystallized quartz grains.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".