ABSTRACT There are limited studies on the mineralogy of tidal flats in Japan even though the composition would affect the functions of water purification and organic matter preservation. This study investigated the mineralogy of major Japanese tidal flats and clarified factors affecting the mineralogy. Sediment samples were collected at 46 sites from 21 tidal flats throughout Japan. Primary minerals in the fine sand fraction and secondary minerals in the clay fraction were identified using a scanning electron microscope equipped with an energy dispersive spectroscope and an X-ray diffractometer, respectively. Active Al and Fe content that reflect the influence of volcanic materials were measured by acid ammonium oxalate extraction. The sediments from Hokkaido and Chiba had higher content of volcanic glasses (mean ± SD: 40 ± 15%) in the fine sand fraction. The sediments from Hokkaido and Chiba had higher ratios of active Al and Fe content to clay content. The sediments from inner regions of the bays (e.g., those from Aichi and Saga) had smectite that forms in the sea and sediment under a rather calm condition in the clay fraction. The sediments from southern Okinawa contained smectite and those from Chiba and Tokushima contained vermiculite that would have come from the soils in the watersheds. Mineralogy of the sediments in the tidal flats was affected by 1) volcanic activity, 2) location of sedimentation, and 3) soils in the watersheds.

中文翻译：

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日本潮滩沉积物的矿物组成

摘要 日本潮滩的矿物组成会影响水净化和有机质保存的功能，但对其矿物学的研究有限。本研究调查了日本主要潮滩的矿物学并阐明了影响矿物学的因素。在日本全国 21 个滩涂的 46 个地点收集了沉积物样本。使用配备能量色散光谱仪和X射线衍射仪的扫描电子显微镜分别鉴定细砂部分中的原生矿物和粘土部分中的次生矿物。采用酸性草酸铵萃取法测定反映火山物质影响的活性铝和铁含量。北海道和千叶沉积物中火山玻璃含量较高（平均值±标准差：40 ± 15%) 在细砂部分。北海道和千叶沉积物的活性铝和铁含量与粘土含量的比率较高。来自海湾内部区域的沉积物（例如来自爱知和佐贺的沉积物）具有在海中形成的蒙脱石和在粘土部分相当平静的条件下形成的沉积物。冲绳南部的沉积物含有蒙脱石，千叶和德岛的沉积物含有蛭石，这些蛭石可能来自流域土壤。潮滩沉积物的矿物学受 1) 火山活动、2) 沉积位置和 3) 流域土壤的影响。来自爱知县和佐贺县的那些）在粘土部分相当平静的条件下在海和沉积物中形成了蒙脱石。冲绳南部的沉积物含有蒙脱石，千叶和德岛的沉积物含有蛭石，这些蛭石可能来自流域土壤。潮滩沉积物的矿物学受 1) 火山活动、2) 沉积位置和 3) 流域土壤的影响。来自爱知县和佐贺县的那些）在粘土部分相当平静的条件下在海和沉积物中形成了蒙脱石。冲绳南部的沉积物含有蒙脱石，千叶和德岛的沉积物含有蛭石，这些蛭石可能来自流域土壤。潮滩沉积物的矿物学受 1) 火山活动、2) 沉积位置和 3) 流域土壤的影响。