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 Cenomanian to Campanian rocks of north-central Montana contain shallow economic accumulations of dry natural gas derived from microbial methanogenesis. The methanogens utilized carbon dioxide derived from organic matter in the marginal marine sediments and hydrogen from in situ pore water to generate methane. The most recent USGS assessment of the shallow gas resources of eastern Montana used a petroleum systems approach, identifying the critical components of a petroleum system (source rock, reservoir rock, seal rock, and trap) and their temporal relationships. As a part of this effort, geochemical data from natural gas wells and associated formation waters were used to identify two microbial gas systems and the timing of methanogenesis. Two microbial gas families are identified in north-central Montana based on stable carbon isotope and gas composition. The Montana Group gas family has heavier δ13C methane values, slightly lighter δD methane values, and a lower carbon dioxide and nitrogen content than the Colorado Group gas family. The two gas families may reflect, in part, the source rock depositional environments, with the Colorado Group rocks representing a more offshore marine depositional environment and the Montana Group rocks representing proximal marine, deltaic and nonmarine depositional environments. Assuming the gas families reflect only source rock characteristics, two microbial petroleum systems can be defined. The first petroleum system, called the Colorado Group microbial gas system, consists of Colorado Group rocks with the shales in the Belle Fourche Formation, Greenhorn Formation, and the Carlile Shale as the presumed source rocks and the interbedded Phillips and Bowdoin sandstones and the Greenhorn Formation limestones as reservoirs. The second petroleum system, called the Montana Group microbial gas system, consists of the Montana Group rocks that include the Gammon Shale and possibly the Claggett Shale as source rocks and the Eagle Sandstone and the Judith River Formation as reservoirs. The Niobrara Formation is tentatively placed in the former system. The geographic extent of the two microbial systems is much larger than the study area and includes an area at least from the Alberta basin to the northwest to the Powder River basin to the southeast. Upper Cretaceous microbial gas accumulations have been recognized along these basin margins at burial depths less than 3000 ft, but have not been recognized within the deeper parts of the basins because subsequent charge of thermogenic oil and gas masks the preexisting microbial gas accumulations. Methanogenesis began soon after the deposition (early-stage methanogenesis) of the Cenomanian to Campanian source sediments, and was either sustained or rejuvenated by episodic meteoric water influx until sometime in the Paleogene. Methanogenesis probably continued until CO2 and hydrogen were depleted or the pore size was compacted to below tolerance levels of the methanogens. The composition of the Montana and Colorado Group gases and coproduced formation water precludes a scenario of late-stage methanogenesis like the Antrim gas system in the Michigan basin. Some portion of the methane charge was originally dissolved in the pore waters, and subsequent reduction in hydrostatic pressure caused the methane to exsolve and migrate into local stratigraphic and structural traps. The critical moment of the microbial gas systems is this timing of exsolution rather than the time of generation (methanogenesis). Other studies suggest that the reduction in hydrostatic pressure may have been caused by multiple geologic events including the lowering of sea level in the Late Cretaceous, and subsequent uplift and erosion events, the youngest of which began about 5 Ma.
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 | 0.001 | 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) | 0.001 | 0.001 |
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