ENREGISTREMENT STRATIGRAPHIQUE DES PHASES D'EMERSION SUR LES PLATES-FORMES CARBONATEES Une étude intégrée à l'affleurement et en sismique de la plate-forme cénomanienne d'Oman (Formation Natih)
Bibliographic record
Abstract
Subaerial exposure of carbonate platforms is generally recorded by karstification and pedogenesis, whereas erosion features such as incisions along emersion surfaces have seldom been observed and studied. However, the recognition of incisions and the characterization of their fill may facilitate sequence boundary definition and hierarchy, especially along exposure surfaces which do not otherwise present clear petrographic evidence for emersion. Within the Natih Formation (Late Albian-Early Turonian, Oman), two successive incision surfaces are found in the upper part of the first third-order depositional sequence. Seismic interpretation of regional subsurface data has allowed the quantification of progradational geometries within the Natih sequence I carbonate platform and the correlation of incision surfaces with forced regressive prograding wedges on the margins of an intrashelf basin. This regional seismic analysis has therefore highlighted the architectural complexities that build third- and fourth-order depositional cycles in interior platform carbonate systems. The heterogeneities associated with emersion phases (incisions, lowstand wedges) are superimposed on this complex stratigraphic framework. Detailed geological sections and correlations have been made from three outcrop localities, allowing a precise description of incision fill geometries and facies, and a comparative analysis of these observations via the integration of incision paleogeographic positions. Morphology, orientation and extent of these incisions have been assessed from detailed seismic interpretation coupled with specific forward seismic modeling. Tidal channels are found at several stratigraphic levels within the Natih Formation. They generally develop during flooding phases of the inner platform. A comparative analysis of these channels and incisions has allowed the recognition of the main elements of differentiation and of similarity between these two types of channelized structures within carbonate platform strata. The integration of outcrop and seismic data sets at the regional and local scales allows the interpretation and discussion of the origin and factors controlling the development of these incisions and a refinement of the stratigraphic model. These two incisions record rapid sea-level variations (500 ky) with a magnitude of approximately 20 and 30 m that occurred during the early Cenomanian. This is probably not a unique case, since for the same time interval, incisions have been observed in siliciclatic systems in western Canada and India and in carbonate systems on the Arabian plate.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| 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".