Eocene Paleoseismic Record of the Green River Formation, Fossil Basin, Wyoming, U.S.A.: Implications of Synsedimentary Deformation Structures In Lacustrine Carbonate Mudstones
Bibliographic record
Abstract
Abstract: Laterally extensive intervals containing sedimentary deformation features are identified in outcrops of lacustrine deposits of the Eocene (∼ 52–51 Ma) Green River Formation in Fossil Basin, southwestern Wyoming. Fossil Basin is the smallest of the paleo-lakes in the Green River system and is located in the Sevier Fold and Thrust Belt, which was tectonically active during deposition. Deformation structures include convolute lamination, load structures, hybrid brittle–ductile features, sedimentary dikes, microfaults, fluid-escape features such as cusps and pipes, oil-shale breccias, and mass-transport deposits. In most cases these structures are hosted by finely laminated, variably organic-rich carbonate mudstones that accumulated in a low-energy profundal lacustrine environment. Deformed intervals range from a few centimeters to 5 m in thickness and are bound above and below by undeformed strata of the same facies, which demonstrates the early post-depositional timing of deformation. The distribution of these features indicates a primary control exerted by sediment rheology, resulting from variation in grain size, clay and organic content, and degree of lithification, which in turn were governed by the depositional environment and early diagenesis. Based on their morphological attributes, lateral extent, and recurrence at different stratigraphic levels, along with their sedimentary environment and the tectonic setting of the basin, the deformation structures are interpreted to be “seismites,” i.e., the result of stresses induced by syndepositional earthquakes, and other potential trigger agents are rejected. Moreover, stratigraphic relationships indicate that these small-scale deformation features as well as the mass-transport deposits, formed on a virtually flat lake floor, ruling out instability caused by the gravitational regime. Syndepositional deformation in Fossil Basin points to tectonic activity along the nearby Absaroka and/or Hogsback thrusts and related fault systems. Seismites point to possible tectonic forcing as a mechanism for changes in bathymetry and sedimentation in the Green River Formation and, consequently, demonstrate their potential for elucidating the tectonic history of other lacustrine and marine basins.
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How this classification was reachedexpand
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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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 teacher head, 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".