Mineralogical composition of tidal flat sediments in Japan. Issue 4 (3rd July 2020)

• Record Type: Journal Article
• Authors: Asakawa, Shota; Watanabe, Tetsuhiro; Lyu, Han; Funakawa, Shinya; Toyohara, Haruhiko
• Is Part Of: Soil science and plant nutrition. Volume 66:Issue 4(2020)
• Page Start: 615
• Page End: 623
• Publication Date: 2020-07-03
• Subjects: Tidal flat -- clay mineralogy -- volcanic activity -- active Al and Fe; Soil science -- Periodicals; Plants -- Nutrition -- Periodicals; 631.4
• DOI: 10.1080/00380768.2020.1787082
• Languages: English
• ISSNs: 0038-0768

Abstract

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.