Rare earth element proxy for distinguishing marine versus freshwater Ediacaran fossils
Bibliographic record
Abstract
Ediacaran fossils and sedimentary rocks are controversial for whether they are marine or non-marine, and this study applies the test of light rare earth over heavy rare earth weight ratios (LYREE/HYREE) to a variety of Ediacaran siliciclastic and carbonate fossil matrices. Holocene soils have light-YREE-enriched arrays (LYREE/HYREE>4.8) and modern deep marine clays have heavy-YREE-enriched arrays (LYREE/HYREE<2.7). Flat arrays of fluvial and shallow marine siliciclastic sediments (LYREE/HYREE 2.7-4.8) are indistinguishable by this proxy. This proxy has been applied to a variety of Ediacaran and Cambrian rocks, for which confounding provenance effects were minimized by comparing marine and non-marine pairs within the same formations. Many samples were within the ambiguous zone (LYREE/HYREE 2.7-4.8), but Ediacaran red beds from Newfoundland, and some beds from China, Namibia, central and South Australia showed diagnostic continental, terrestrial LYREE/HYREE weight ratios of 4.8 to 11.3. A grey tempestite from Newfoundland, a grey sandstone from California, and grey dolostones from Australia and Namibia showed marine LYREE/HYREE weight ratios of 2.7 or less, from the same provenance as terrestrial samples. This new criterion for distinguishing marine from non-marine Ediacaran rocks is supported also by boron content, Ge/Si ratios, and eolian interbeds. Furthermore, new analyses correctly interpreted trilobite and Cloudina beds as marine. One surprisingly secure result is that fossiliferous Ediacaran rocks of Newfoundland were not formed in a deep ocean, but on coastal plains. Some fossiliferous Newfoundland beds have LYREE/HYREE weight ratios of as much as 6.0-11.3, found only in paleosols.
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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 | 0.001 | 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) | 0.002 | 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".