First Detrital Zircon Provenance Data from Oligocene-Pleistocene Sediment in the Beaufort-Mackenzie Basin, Arctic Ocean
Bibliographic record
Abstract
Sediment, runoff, and nutrient input to the Arctic Ocean plays a critical role in both physical and biological processes that impact regional and global systems. The Beaufort-Mackenzie Basin, situated in the Arctic Ocean offshore northwestern Canada, contains more than 14 km of clastic strata and provides a record of erosion and sediment transport from the Cretaceous to present. Pliocene sedimentation rates within the basin jump nearly 2000% relative to underlying units, but the cause of this shift remains unknown. We used cuttings from the N. Issungnak L-86 well, focusing on the Oligocene-lower Miocene Kugmallit and Mackenzie Bay sequences and the Pliocene-Pleistocene Iperk sequence for U-Pb geochronology analysis. Overall, these units have consistent zircon populations with peaks at roughly 100, 400, 1200-1800, and 2700 Ma, indicating a relatively consistent sediment provenance between Oligocene and Pleistocene time. Based on the similarities between populations in our samples and those in the Northern Cordillera of Canada, we interpret that sediment in the Beaufort-Mackenzie Basin was derived from the adjacent mountains. Differences in populations of 0-300 Ma zircon grains between the Kugmallit-Mackenzie Bay and Iperk sequences suggest the drainage basins in this region evolved as the river system responsible for the Kugmallit-Mackenzie Bay sequences was redirected and an alternate river system delivered sediment to the Pliocene Iperk sequence. This change was likely caused by tectonic rock and surface uplift in the region associated with a Late Miocene-Early Pliocene episode of regional deformation.
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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 | 0.001 | 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".