Биостратиграфия славгородского горизонта (сантон нижний кампан) юго-востока Западной Сибири
Bibliographic record
Abstract
The paper considers recent data of the investigation on foraminifera and biostratigraphy of the Slavgorodskian Horizon dated to the Santonian Early Campanian. Eighteen core samples were analysed from the borehole ZN-4 section (the vicinity of town Seversk) in the southeast of Western Siberia. The foraminiferal assemblages were encountered at three stratigraphic levels: the Lower Santonian beds with the Haplophragmoides tumidus Assemblage (the Ammobaculites dignus Pseudoclavulina admota Zone) the Upper Santonian beds with the Ammomarginulina crispa Assemblage (the Cribrostomoides exploratus Ammomarginulina crispa Zone) and the Lower Campanian beds with the Recurvoides magnificus Assemblage (the Bathysiphon vitta Recurvoides magnificus Zone). Three palaeontological plates illustrate the main species of agglutinated quartz-siliceous and secreted-calcareous foraminifera. The Early Santonian assemblage encountered here is dominated by species of the Haplophragmoididae Family, of which index-species Haplophragmoides tumidus was established for these beds. In the middle beds of the Slavgorodskian Horizon, the assemblage is dominated by coarse-grained agglutinated tests and the index-species Ammomarginulina crispa among them. In the central district this index-species was established in the Upper Santonian beds along with the other characteristic species Cribrostomoides exploratus Podobina that is missing in the borehole ZN-4 section. In the upper beds of the Slavgorodskian Horizon, the systematic composition of the assemblage is significantly renewed, and the Recurvoides magnificus Podobina Species known for the Lower Campanian appears along with the species of agglutinated tests met previously. The species of the secreted-calcareous tests also occur, that are characteristic for this part of the section and migrated here from the southern (Kazakhstan) province. The systematic composition of large agglutinated coarse-grained tests is similar to that from the central district, where the Arctic Regions influenced the relatively cold-water basin of Western Siberia. The significant similarity of these West-Siberian foraminifera is also observed with the forms from Canada and Northern Alaska assigned to the Arctic Palaeozoogeographic Realm. Southern immigrants entering the assemblage commonly as pseudomorphs and rare secreted-agglutinated tests are similar in taxonomy to the species from Kazakhstan and East-European provinces of the Boreal-Atlantic Realm. The mixed taxonomic composition of foraminifera from various provinces enabled the Santonian Early Campanian age of the Slavgorodskian Horizon to be established from these two ways (northern and southern). The shallow-water coastal environmental conditions for the studied foraminiferal tests left their imprints on their aspects and systematic composition. In the borehole ZN-4 section, the Santonian Lower Campanian beds containing varied index-species are correlatable with the widespread foraminiferal zones. The lithologo-microfaunal characterization of the studied section beds and their correlatability with the established foraminiferal zones is presented in the table.
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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 | 0.001 |
| 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 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.013 | 0.004 |
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".