First-Cycle Grain Weathering Processes: Compositions and Textures of Sea Glass from Port Allen, Kauai, Hawaii
Bibliographic record
Abstract
Abstract Chemical and mechanical weathering textures on siliciclastic grains have provided important information concerning depositional processes and environments, yet understanding is limited by the multicycle origin of most sedimentary deposits. Sea glass grains sampled from a beach in Port Allen, Kauai, Hawaii, were analyzed for mechanical and chemical weathering features using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and X-ray photoelectron spectroscopy (XPS). As a result of a proximal dumping-ground source, the sea glass offers a unique opportunity to study first-cycle grain weathering processes in a moderate- to high-energy shoreline environment. Grain-size analysis indicates that the largest grains are located behind natural barriers, such as outcrops and boulders. The best-sorted samples are from the lower to middle foreshore environment, whereas moderately sorted deposits are located closer to the backshore where storm waves predominate. Although there is no preferred distribution of different-colored sea glass grains on the beach, nonfrosted grains predominate over frosted varieties, suggesting constant input of fresh material. Grain surface textures can be divided into mechanically dominated and chemically dominated weathering groups. Evidence of mechanical weathering is provided by conchoidal fractures, crescentic gouges, and straight grooves, whereas chemical weathering is indicated by c-shaped cracks, halite (salt) and silica precipitation, and solution pits. Combinations of these features demonstrate that both weathering processes work together to degrade the grains. XPS depth profiling of individual grains indicates that chemical weathering occurs at different grain depths, with leaching of sodium from the glass surfaces. This study provides a rare opportunity to relate grain compositions and textures with depositional and weathering processes, due to the first-cycle origin of the sea glass. The results show that using XPS and SEM techniques is a broadly applicable approach toward unraveling chemical and mechanical breakdown of sediment in beach environments.
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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 | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".