The study of crystal structure in the evolution of interstratified 2:1 clay minerals, Reindeer D-27 well, Mackenzie Delta - Beaufort Sea region, Arctic Canada /
Bibliographic record
Abstract
Owing to the conflicting results obtained from the application of different analytical and sample preparation techniques, and to the complex nature of interstratified 2:1 clay minerals, the compositional and structural changes that occur with increasing diagenetic grade in illite-smectite (IS) mixed layers had not been adequately deciphered previously. Some of the uncertainties result from different modes of sample preparation, namely ion-beam milled original rock samples and dispersed separates. I have used a combined approach of n-alkylammonium cation exchange of 2:1 clay minerals, XRD, HRTEM, CTEM of Pt-C replicas of adsorbed and freeze-fractured specimens after cryofixation, and K-Ar dating is used to investigate nucleation and growth characteristics of 2:1 clay minerals from argillaceous rocks of the Reindeer D-27 well, Mackenzie Delta-Beaufort Sea (MDBS) region, Arctic Canada. In addition, three reference 2:1 clay minerals (Zempleni illite, rectorite, and Mancos Shale) were studied. Alkylamrnonium cation exchange of 2:1 clay minerals for investigation by XRD and TEM showed that the diagenetic evolution of smectite to illite in argillaceous rocks of the Reindeer D-27 well cannot be considered as a single, continuous and progressive reaction series as is conventionally proposed. It is rather a prograde sequence of discrete, multiple phases that coexist in overlapping depth intervals. K-Ar dating of illitic phases after treatment with octadecylammonium cations was undertaken to clarify the origin of octadecylammonium intercalated illite, account for its contribution to K-Ar ages, and assess the presence of detrital illitic phases in fine clay-size separates. Results suggested that K and Ar are removed to different degrees from both detrital and diagenetic components with treatment. By correlating the internal structure of the 2:1 clay minerals with the surface morphology, it was possible to show that the original stacking order of interstratified 2:1 clay minerals can be deciphered using dispersed separates, and that suitable techniques of sample preparation and dispersion can be employed to avoid disrupting the primary texture. In diagenetic samples from Reindeer D-27, the neoformed crystals have unique euhedral morphology, suggesting primary growth as free particles, rather than being disarticulated fragments of larger crystals, as proposed by the investigation of ion-milled specimens of original rock. Investigation of the reference samples of Zempleni illite, rectorite, and Mancos Shale showed that the original stacking order of the 2:1 clay minerals is not destroyed by sample preparation and dispersion. The results suggest that the concept of fundamental particles can be applied to illitic material formed in the early stages of diagenesis, but not necessarily to illitic material formed in other geologic environments such as hydrothermal and contact metamorphic environments. In addition, it was shown that the application of the technique of n-alkylammonium cation exchange for TEM is useful for the study of the evolution of S → I and isotopic dating of illitic clay minerals.
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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 | 0.000 |
| 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) | 0.000 | 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 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".