Paleoproterozoic Gowganda glaciation and implications
Bibliographic record
Abstract
Previous paleomagnetic studies of the glaciogenic Gowganda and Lorrain formations have identified several low-inclination magnetic components of high thermal stability, which suggest low-latitude glaciation during deposition of the Huronian Supergroup, Canada. While extraordinary claims demand extraordinary proof, prior authors have been unable to support their interpretations of these components conclusively with any of the classic field stability tests (e.g., conglomerate, fold, and baked contact) capable of demonstrating that the magnetization was acquired at or soon enough after the time of deposition to be used to constrain the paleolatitude of the Gowganda or Lorrain formations. We report here the results of a fold test from the bpurple siltstoneQ member of the Lorrain Formation near the town of Desbarats, Ontario, which indicate that none of the reported components dates to the time of deposition. Hence, the paleolatitude of the Gowganda glaciation is uncertain. Comparison of the lithostratigraphic, paleomagnetic, and radiometric constraints on the Huronian sequence and the Transvaal Supergroup of Southern Africa implies that the one verified low-latitude Paleoproterozoic glacial event (the Makganyene glaciation, Transvaal Supergroup, South Africa) is younger than the three glacial units of Canada. With this correlation, the physical rock record indicates that the dgreat oxygenation eventT began in the time interval between the Gowganda and Makganyene glaciations. These data are consistent with the sudden evolution of oxygenic photosynthesis destroying a methane greenhouse and thereby triggering the first Snowball Earth event in Earth history. D 2005 Elsevier B.V. All rights reserved.A negative fold test on the Lorrain Formation of the Huronian Supergroup: Uncertainty on the paleolatitude of the
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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 | 0.001 |
| Open science | 0.000 | 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".