Miocene alkaline felsic intrusion (syenite), enriched in F, Li, Nb, Ti, Y, REE, Th, Zn, Ba, Zr. Cut by a peralkaline rhyolite dyke with miarolytic cavities. The occurence is of interest to economic geologists because of the unusual concentration of some of these elements in an unusual (nonpegmatitic) environment. REE content for example is 453 ppm, the highest of any japanese granitoid rock.
Note: This area is part of Ashizuri-Uwakai National Park, so hammering on rocks by mineral collectors would not be appropriate. (There are also a number of prehistoric megalithic sites here, many of which were deliberately and unforgivably destroyed by park landscapers in 1977.)
Ref: ISHIHARA Shunso, TANAKA Tsuyoshi, TERASHIMA Shigeru, TOGASHI Shigeko, MURAO
Satoshi, KAMIOKA Hikari (1990): Peralkaline Rhyolite Dikes at the Cape Ashizuri: A New Type of REE and Rare Metal Mineral Resources, Mining Geology, 40, 2 (no.220), 107-115
