Abstract
Although sand colors have influences on a variety of functions, such as coastal landscapes and beach ecological systems, they have never been research subjects in the coastal engineering area. The purposes of the present study are to clarify color characteristics of sands which were collected at 23 beaches in Japan and to examine relationships between the color characteristics and geological features of river drainage areas which are adjacent to the beaches. PCA ordinations showed that the 23 beach sands colors can be well ordinated in a coordinate plane which has axes of brightness and of black to brown. It was confirmed that the brightness of the sand is well explained by area ratios of the felsic rock and of mafic rock, by examining the relationships between the beach sand colors and the igneous rocks.
