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 SiO₂‐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 SiO₂ (~ 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 SiO₂ 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.

中文翻译：

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日本三内丸山遗址绳文时期绿色抛光石轴的岩石学，研究烃源岩的起源

在绳纹时期（5.9-4.2 cal yr BP），日本最大的考古遗址之一的三内丸山遗址（Sannai-Maruyama site），已挖掘出许多绿色的抛光石轴。轴由具有特殊质地的弱变质细粒火山碎屑岩组成，包括在石英和钠长石基质中沿随机方向生长的许多针状阳起石。在北海道南部Biratori镇的努卡比拉河沿岸发现的Aotora石材卵石是这些石材轴线最有可能的原材料。奥托拉石具有交替的带状，即软的深绿色苦味层和硬的SiO ₂富含浅绿色层。浅绿色层的质地类似于石斧。Sorachi-Yezo带的玄武质和微火山岩沿努卡比拉河的支流Shidoni河沿岸占领。火山碎屑岩的质地，矿物学和块状岩石成分与奥托拉石相似，都暴露在该区域。这些岩石在阳起石-斜方晶石相条件下经历了变质作用。他们的原石是海底的碎屑碎屑岩，中间夹有叠层的苦味粉屑。Shidoni河地区的石轴，浅绿色的Aotora石层以及火山碎屑岩的SiO ₂高（〜55 wt％），Cr（〜840μg/ g）和Ni（〜370μg/ g）。具有丰富的轻质稀土元素和石轴耗尽的重稀土元素的稀土元素形态也与露头的浅绿色层一致。这些浅绿色层与苦味碎屑的深绿色层交织在一起，可能是石轴的源岩。浅绿色层中的高SiO ₂含量导致基体中石英和钠长石的结晶，从而产生了用于制造石斧的高质量原材料。