Cyclostratigraphic calibration of the Eifelian Stage (Middle Devonian, Appalachian Basin, Western New York, USA)
Bibliographic record
Abstract
Abstract Over the past decade the integration of astrochronology and U/Pb thermal ionization mass spectrometry dating has resulted in major improvements in the Devonian time scale, which allowed for accurate determination of ages and rates of change in this critical interval of Earth history. However, widely different durations have been published for the Middle Devonian Eifelian stage. Here we aim to solve this discrepancy by building an astronomically calibrated time scale using a high-resolution geochemical data set collected in the early to late Eifelian outer-ramp and deep-shelf deposits of the Seneca section (Appalachian Basin, Western New York, USA). The Middle Devonian Eifelian Stage (GTS2012; base at 393.3 ± 1.2 m.y. and duration estimate of 5.6 ± 1.9 m.y.), is bracketed by two major bioevents, respectively the Choteč event at its base and the Kačák event just prior to the Eifelian–Givetian boundary. To capture the record of Milankovitch-scale climatic cycles and to develop a model of the climatic and oceanographic variations that affected the Appalachian Basin during the Eifelian, 750 samples were collected at typically 2.5 cm intervals across the Seneca section. Major and trace elements were measured on each sample with an inductively coupled plasma–optical emission spectrometer. To estimate the duration of the Seneca section sampled, we applied multiple spectral techniques such as harmonic analysis, the multi-taper, and evolutionary spectral analysis, and we tuned the Log10Ti series using the short orbital eccentricity ∼100 k.y. cycle. Then, to assess the reliability of our cyclostratigraphic interpretation we ran the Average Spectral Misfit method on selected proxies for detrital input variation. The estimated duration derived using this method falls in the range of durations estimated with the tuning method. Using the approximate position of the Emsian–Eifelian and Eifelian–Givetian boundaries, constrained within <1 m, the proposed estimation of the total duration of the Eifelian age is ∼5 m.y. Interpolated from the high-resolution U-Pb radiometric age available for the Tioga F Bentonite, the numerical ages of the Emsian–Eifelian and the Eifelian–Givetian were respectively recalibrated at 393.39 Ma and 388.24 Ma. The uncertainty from the radiometric date is respectively ± 0.86 Ma and ± 0.86 Ma.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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 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".