A continental record of the late Campanian negative carbon isotopic excursion (LCE, late Campanian event) in the Dinosaur Park Formation, Alberta, Canada
Bibliographic record
Abstract
The Campanian was the longest stage of the Late Cretaceous and witnessed multiple global carbon cycle disruption episodes, including the negative carbon isotope excursion (CIE) known as the Late Campanian Event (LCE). However, Campanian-aged δ 13 C perturbations are primarily documented in marine environments, raising questions about their record in terrestrial settings and the potential use of terrestrial stable carbon isotope records from the Campanian as a chemostratigraphic tool. In this study, we present a stable carbon isotope record from fossil organic matter preserved in the alluvial floodplains of the Dinosaur Park Formation, which is radiometrically dated to the time interval containing the LCE. Results reveal a ∼ 0.8 ‰ negative CIE recorded in floodplain fossil organic matter. We show that the negative CIE is not a result of changing organic matter or diagenesis and that it likely reflects the global atmospheric δ 13 C signal during the Campanian. We interpreted the identified negative CIE as a continental record of the LCE. When we couple our δ 13 C TOC record with the Dinosaur Park Formation’s age model, we can correlate our section with other well-dated European marine stratigraphic sections. Our findings demonstrate that Campanian carbon cycle perturbations are preserved in terrestrial environments. For the first time, we recognize that the deposition of the world-famous dinosaur-bearing Dinosaur Park Formation in Alberta was contemporaneous with a major global carbon cycle perturbation episode. Our findings contribute to contextualizing ongoing research and re-evaluating previous studies on dinosaur evolution and other contemporary groups, within the framework of planetary-scale Earth system disturbances. • The Dinosaur Park Formation (DPF) records a global δ 13 Cᴛᴏᴄ signal. • Deposition of the lower portion of the DPF was contemporaneous with the LCE. • Floodplains of the DPF serve as a chemostratigraphic tool for the late Campanian.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 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 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".