Last interglacial sea-level history from speleothems: a global standardized database
Bibliographic record
Abstract
Abstract. Cave deposits are powerful archives for reconstructing past sea levels as they are generally protected from weathering and erosion by their location and can be dated with U-series methods. Two main categories of cave deposits are recognized as sea level indicators: phreatic overgrowth on speleothems (POS) and submerged vadose speleothems (SVS). POS have the great advantage that they precipitate on preexisting vadose supports at a brackish water level equivalent to sea level when air-filled chambers of coastal caves are flooded by rising sea. SVS are also useful, but sea level is inferred indirectly as periods of growth provide constraints on maximum sea level positions, whereas growth hiatuses, sometimes difficult to observe, may indicate times when cave passages are submerged by sea high stands, hence they record minimum sea level elevations. Here we describe a compilation that summarizes the current knowledge of MIS 5 (sensu lato) sea level captured by cave deposits. We used the framework of the World Atlas of Last Interglacial Shorelines (WALIS), a comprehensive sea level database, to provide a standardized format in order to facilitate scientific research on MIS 5 sea level. The discussion is MIS 5e-centered, but records that capture MIS 5c and 5a are also included. We present the data from 59 cave deposits (26 sea-level index points and 33 limiting points) in coastal caves located in eight different locations, and we include the spatial coverage, the samples used and their accuracy as indicators of sea level, the isotopic characteristics used to generate the U-Th chronologies, and their scientific relevance to understand past sea-level changes. The paper also emphasizes how some of these indicators are useful not only for the information they offer about the eustatic sea level, but more importantly: i) those from tectonically stable areas provide information on Earth deformation and regional ice sheet histories, thus refining the glacial isostatic adjustments models and ii) those from active regions can constrain regional tectonic uplift rates. The standardized sea-level database presented here is the first of its kind derived from cave deposits and contains all the information needed to assess former paleo relative sea level and the chronological constraints associated with them. The database is available open-access at http://doi.org/10.5281/zenodo.4313861 (Dumitru et al., 2020).
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.014 | 0.018 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 0.004 |
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".