Deciphering hydrocarbon evolution history of the Cambrian shales in tectonically complex basins: Constraints from calcite U-Pb dating and low-temperature thermochronology
Bibliographic record
Abstract
Assessing hydrocarbon evolution of organic-rich shales in tectonically complex basins is critical for shale gas resource evaluation. A major obstacle is the difficulty in precisely constraining the timing of hydrocarbon migration and leakage events. Here, fluid inclusion microthermometry, calcite U-Pb and detrital zircon (U-Th)/He dating were integrated to reconstruct the hydrocarbon evolution history of the Cambrian organic-rich shales in the southeastern margin of the Upper Yangtze Platform. We assessed the dynamic evolution of shale gas content over time by methane isothermal adsorption coupled with geothermometry and geobarometry . The calcite veins yield U-Pb ages of 113.5–108.9 Ma (C1 calcite) and 65.5–65.2 Ma (C2 calcite), with fluid inclusion trapping temperatures of 186.2 °C and 74.8 °C, respectively. Detrital zircon (U-Th)/He dating indicate that the basin inversion started at the Middle Triassic (ca. 241 Ma), leading to a cooling in the shales. The onset of intense exhumation and folding deformation occurred at ca. 113Ma, which corresponds to the Yanshanian Orogeny . This tectonic deformation event triggered the opening of fractures (as indicated by the formation of the C1 calcite veins with ages of ca. 114–109 Ma), facilitating shale gas migration and leakage, with a shale gas loss of at least 0.75 cm 3 /g. These results demonstrate that combination of fluid inclusion and geochronological data can provide accurate geochronological constraints on shale gas migration and leakage associated with tectonic uplifts, which can be an effective approach to decipher hydrocarbon evolution history of shales in tectonically complex basins worldwide.
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.
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 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".