Paleogene sedimentation and Eurekan deformation in the Stenkul Fiord area of southeastern Ellesmere Island (Canadian Arctic): Evidence for a polyphase history
Bibliographic record
Abstract
ABSTRACT Field studies and interpretative mapping of the area southeast of Stenkul Fiord (Ellesmere Island) revealed that the Margaret Formation clastic deposits consist of at least four sedimentary units (Units 1–4) separated by unconformities. Several centimeter-thick volcanic ash layers, identified within coal layers and preserved as crandallite group minerals (Ca-bearing goyazite), suggest an intense volcanic ash fall activity. Based on new U-Pb zircon dating (ID-TIMS) of three ash samples from one layer, this activity took place at 53.7 Ma in the early Eocene, i.e., within the period of the Eocene Thermal Maximum 2 hyperthermal. This age further suggests that the lowermost Unit 1 can be assigned to the late Paleocene–earliest Eocene, Unit 2 to the early Eocene, whereas Units 3 and 4 might be early to middle Eocene in age. Sedimentation was followed and partly accompanied by compressive Eurekan deformation after ~53.7 Ma, which led to the formation of fold and fault structures. Several pulses of deformation caused uplift and erosion and were followed by sedimentation of the next unit above an unconformity. Deformation presumably ended before the middle Eocene. An earlier phase of probably extensional Eurekan deformation in Unit 1 can be assigned to the latest Paleocene–earliest Eocene. These results show that Paleocene/Eocene sedimentation and Eurekan deformation represent a protracted history comprising several phases of ongoing clastic sedimentation, deformation, uplift, and erosion. This suggests that the Eurekan deformation on Ellesmere Island cannot be assigned to a single fixed time in the Paleogene only.
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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".