A long-lasting tenuous Ediacaran geodynamo: potential linkages with the evolution of animal life
Bibliographic record
Abstract
Paleointensity studies define a geodynamo on the verge of collapse [1,2,3], 10 to 30 times weaker than present-day, when macroscopic animals of the Ediacaran Fauna diversified.New single crystal paleointensity results from ca. 590 Ma dikes of Canada yield field strength of hundreds of nanoteslas (or less) suggesting that the dynamo may have ceased entirely for periods lasting 2 to 100 kyr during the Ediacaran.For times when the field was present, use of solar wind evolution models based on solar analogs [4] suggests steady-state magnetopause standoff distances <4.5 Earth radii (re) at 565 Ma and <4.2re at 591 Ma, compared to the present-day value of 10.7re.During extreme coronal mass ejection events, these distances could have been as low as 1.6re.Decreased standoff distances can lead to enhanced hydrogen escape because the polar cap area of open field lines expands, and this is where non-thermal H+ loss occurs.Estimates of these losses to space suggest they could result in a few percent change of atmospheric oxygen (PAL).This might represent a perturbation or crossing of a threshold, allowing Ediacaran animal diversification.
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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) | 0.000 | 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)
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".