Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract The δ 13 C profile from an interval of the Martin Point section in western Newfoundland (Canada) spans the upper Furongian (uppermost Cambrian). The interval (~90 m) is a part of the Green Point Formation of the Cow Head Group and consists of the Martin Point (lower) and the Broom Point (upper) members. It is formed of slope marine carbonates alternating with shales (rhythmites) and conglomeratic interbeds. The preservation of the investigated micritic carbonates was meticulously evaluated by multiple petrographic and geochemical screening tools. The δ 13 C and δ 18 O values (−0.5 ± 0.8 ‰VPDB and −7.1 ± 0.3 ‰VPDB, respectively) exhibit insignificant correlation ( R 2 = 0.002) and similarly the correlation of δ 13 C values with their Sr and Mn counterparts, which supports the preservation of at least near-primary δ 13 C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ 13 C profile exhibits two main negative excursions, a lower broad excursion (~3 ‰) that reaches its maximum at ~70 m below the Martin Point / Broom Point members boundary and an upper narrow excursion (~2.5 ‰) immediately below the same boundary. The lower excursion can be correlated with the global latest Furongian HERB event (TOCE), which is also recognized in the C-isotope profile of the GSSP boundary section at Green Point whereas the upper excursion matches with that of the Cambrian‒Ordovician boundary in the same section. The peak of the HERB δ 13 C excursion is correlated with positive shifts on the Th/U and Ni profiles (redox and productivity proxies).
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.
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) | 0.000 | 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 it