Petrology of green polished stone axes of the Jomon period from the <scp>Sannai‐Maruyama</scp> site, Japan, investigating the origin of source rock
Bibliographic record
Abstract
Abstract Numerous green polished stone axes have been excavated from the Sannai‐Maruyama site, one of Japan's largest archeological sites in the Jomon period (5.9–4.2 cal kyr BP). The axes are composed of weakly metamorphosed fine‐grained volcaniclastic rock having a peculiar texture that includes numerous acicular actinolites growing in random directions within a quartz and albite matrix. Cobbles of Aotora stone found along the Nukabira River, Biratori town, southern Hokkaido, are the most likely raw material for these stone axes. Aotora stones have alternate bands of a soft dark‐green picritic layer and a hard SiO 2 ‐rich pale‐green layer. The pale‐green layer has a texture similar to the stone axes. Basaltic and picritic volcanic rocks of the Sorachi‐Yezo Belt occupy the area along the Shidoni River, a tributary of the Nukabira River. Volcaniclastic rocks similar in texture, mineralogy, and bulk rock compositions to the Aotora stone are exposed in the area. These rocks underwent metamorphism under the actinolite‐pumpellyite facies conditions. Their protolith is submarine hyaloclastic rocks that are intercalated with laminated picrite detritus. The stone axes, pale‐green layers of Aotora stone, and those of the volcaniclastic rocks of the Shidoni River area all have high SiO 2 (~ 55 wt%), Cr (~ 840 μg/g), and Ni (~ 370 μg/g). The rare earth element patterns with abundant light rare earth elements and depleted heavy rare earth elements of stone axes were also consistent with the pale‐green layers of the outcrop. These pale‐green layers, interleaved with dark‐green layers of picritic detritus, were the likely source rock of the stone axes. The high SiO 2 content in the pale‐green layer caused the crystallization of quartz and albite in the matrix, which resulted in high‐quality raw material for making stone axes.
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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 | 0.000 | 0.001 |
| 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 | 0.001 | 0.000 |
| 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 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".