On the possibility of a complete Ediacaran field collapse
Bibliographic record
Abstract
<!--!introduction!--><b></b> In the past decade there has been increased multidisciplinary interest in the onset time of inner core nucleation (ICN). A major step forward toward understanding ICN from paleomagnetism was the discovery by Bono et al. (<em>Nature Geoscience</em>, 2019) of ultralow fields in Ediacaran-age (565 Ma) anorthosites of the Sept Îles layered mafic sequence of northern Quebec, Canada. Independent thermal and numerical dynamo modeling (Driscoll, <em>GRL</em>, 2016) predicted the weak-field state prior to ICN. Bono et al. (2019) combined the unusual geomagnetic behavior (a hyper-reversal state) from global studies together with the Sept Îles ultra-low field value to suggest ICN near 565 Ma. We consider whether the internally generated field did not just decline to ultra-low values but might have effectively disappeared for some time interval of the Ediacaran Period. We study whole rock paleointensity values from Ediacaran-age dikes sampled from Ontario, Canada. We find Arai plots with extreme two-slope behavior. The low temperature slope appears to be a thermo-viscous overprint, whereas the high temperature slope, if interpreted as a viable paleointensity measure, records ultra-low fields. The whole rocks almost certainly contain some large multidomain grains. Here we investigate the possibility that the high temperature slope is a field overestimate, reflecting not the true ambient field but rather the dominant viscous overprint that has contaminated higher unblocking temperatures. If correct, it is further possible that this overprint might be concealing even lower ambient fields, or a complete collapse of the dynamo. We will discuss our plans to experimentally assess this hypothesis.
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 | 0.003 | 0.004 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".