Time, space and synoptic topography: how to read outcrops as a granular record of Earth history
Bibliographic record
Abstract
Siliciclastic strata commonly preserve chronostratigraphic surfaces that record the ancient interface of sediment and water/air, in the form of true substrates on bedding planes and sampled topography in stratigraphic profiles. Such surfaces are commonly a reflection of sedimentary stasis, a sedimentation state where neither deposition or erosion was occurring. Sedimentary stasis may be instantaneous, temporary or prolonged, and may also be considered to occur when the constituent grains of a substrate remain in motion as the surface active layer, when the elevation of the lithic surface does not change. The preservation of patches of synoptic topography requires only that sedimentation states of deposition, erosion and stasis fluctuate, but is more common in lower energy parts of a depositional environment. Certain sedimentary features associated with true substrates and sampled topography can, through modern analogy, be used to determine the likely duration of sedimentary stasis. Here we use original case studies to show how the duration of this stasis can be variable depending on facies and stratal age, but that at outcrop scale it is always a very short interval relative to the longevity of a depositional environment. With examples from several siliciclastic facies and geological periods, we show that stratigraphic time preserved at outcrop scale can be very short, indicating that the total stratigraphic record is built brick-by-brick from many lower hierarchy snapshots. This understanding shifts perspectives on the stratigraphic record as an archive, with implications for the meaning of sedimentary signatures at outcrop and the construction of narratives to understand Earth history.
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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 | 0.003 | 0.032 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.005 |
| Science and technology studies | 0.001 | 0.004 |
| Scholarly communication | 0.009 | 0.015 |
| Open science | 0.001 | 0.003 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.009 | 0.003 |
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".