The thermal structure of subduction zone back arcs
Why is this work in the frame?
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Full frame distilled prediction
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.
- Candidate categories
- Insufficient payload (model declined to judge)
- Consensus categories
- none
- Domain
- Candidate signal: noneConsensus signal: none
- Study design
- Candidate signal: ObservationalConsensus signal: none
- Genre
- Candidate signal: EmpiricalConsensus signal: Empirical
- Teacher disagreement score
- 0.817
- Threshold uncertainty score
- 1.000
- Validation status
machine_predicted_unvalidated·codex-gemma-dda1882f352a
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) | 0.001 | 0.000 |
Machine scores (provisional)
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
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.
- Teacher spread
- 0.248 · how far apart the two teachers sit on this one work
- Validation status
score_only:v0-immature-baseline· verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it
Abstract
It is well recognized that active arc volcanism at nearly all subduction zones requires temperatures greater than 1200°C in the subarc mantle, despite the underthrusting cool subducting plate. In this study, we document evidence that high upper mantle temperatures are not restricted to the arc but usually extend for several hundred kilometers across the back arc, even in areas that have not undergone extension. For 10 circum‐Pacific back arcs where there has been no significant recent extension, we have compiled observational constraints on the thermal structure using a number of independent indicators of mantle temperature, including surface heat flow, seismic velocity, and xenolith thermobarometry. The observations indicate uniformly high temperatures in the shallow mantle and a thin lithosphere (1200°C at ∼60 km depth) over back‐arc widths of 250 to >900 km. Similar high temperatures are inferred for extensional back arcs of the western Pacific and southern Europe, but the thermal structures are complicated by extension and spreading. A broad hot back arc may be a fundamental characteristic of a subduction zone that places important constraints on back‐arc mantle dynamics. In particular, the thermal structure predicted for slab‐driven corner flow is inconsistent with the observed uniformly high back‐arc temperatures. We favor the alternate model that heat is rapidly carried upward from depth by vigorous thermal convection in the back‐arc upper mantle. Such convection may be promoted by low viscosities, resulting from hydration by fluids from the subducting plate. Following subduction termination, we find that the high temperatures decay over a timescale of about 300 Myr.
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.
The record
- Venue
- Journal of Geophysical Research Atmospheres
- Topic
- High-pressure geophysics and materials
- Field
- Earth and Planetary Sciences
- Canadian institutions
- Geological Survey of CanadaUniversity of VictoriaDalhousie University
- Funders
- not available
- Keywords
- SubductionGeologyMantle (geology)LithosphereGeophysicsVolcanic arcBack-arc basinMantle wedgeHotspot (geology)SlabMantle convectionSeismologyPlate tectonicsThermalConvectionTectonicsMechanics
- Has abstract in OpenAlex
- yes