Phanerozoic record of northern Ellesmere Island, Canadian High Arctic, resolved through 40Ar/39Ar and (U-Th)/He geochronology
Bibliographic record
Abstract
Geochronological studies illuminate our understanding of the tectono-stratigraphic evolution of the Arctic Ocean, submarine features, continental shelves and adjoining landmasses. The Franklinian and Sverdrup basins of the Canadian High Arctic preserve a near-continuous Phanerozoic succession detailing the geologic evolution of the northern Laurentian margin from the Neoproterozoic to Cenozoic. Whereas previous studies have documented the structural and stratigraphic record of several episodes of orogenesis and first-order depositional cycles related to Circum-Arctic evolution, supporting geochronological data are sparse because the logistical challenges associated with fieldwork at high latitudes resulting in poor temporal resolution on the magnitude and timing of: 1) accretion of the Pearya terrane to the Laurentian margin; 2) the Devonian to Carboniferous Ellesmerian orogeny; and 3) Paleogene Eurekan deformation. In an effort to constrain the age of these tectonic episodes, we applied 40Ar/39Ar and (U-Th)/He low-temperature geochronology to major polydeformed NE-SW trending strike-slip fault zones that bisect the Pearya terrane and Franklinian Basin of northern Ellesmere Island, Canada. Total fusion 40Ar/39Ar dating was conducted on 165 single muscovite grains from 22 samples. Age dispersion was sample dependent, with some samples exhibiting robust Paleozoic ages corresponding to the assembly and accretion of the Pearya terrane, and other samples yielding intra-sample date dispersion that spanned the late Paleozoic and Mesozoic, indicative of a previously unreported post-Ellesmerian and pre-Eurekan history. Zircon (U-Th)/He dates from 11 samples (n: 73) and apatite (U-Th)/He data from 6 samples (n: 21) are largely Eocene in age, with dominant populations of c. 48 Ma and c. 41 Ma, respectively. Inverse thermal history modelling of (U-Th)/He data indicates episodic Mesozoic burial and unroofing that coincide with changes in the regional stress regime from dominant N-S to WNW-ESE compression, and rapid cooling during the nascent (>53 Ma) and initial (53 Ma to 47 Ma) phases of Eurekan deformation. The improved geochronologic resolution of the eastern Canadian High Arctic will allow better correlation to offshore structural features and to deformation events on the Greenland plate and Svalbard archipelago.
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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 source (direct Gemma or distilled Codex), 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".