R6: Plutonic rocks, volcanic rocks and subduction factory

[R6-03] Petrography of Shikanoshima basic rocks at Itoshima Peninsula.

Mio Ifuku¹, *Tomoharu Miyamoto¹, Kazuhiko Shimada¹ (1. Kyushu Univ. Sci.)

Keywords:Shikanoshima Basic rock, Hornblende

The Shikanoshima basic plutonic rocks are emplaced at the northern Fukuoka. At the southwest of Itoshima Peninsula, the mafic rocks were commonly composed mainly of hornblende, plagioclase, and quartz, with minor amount of biotite and microcline subsequently. In the medium and coarse grain mafic rocks, some euhedral Hbl were colored green uniformly and others had a brown color near the core and a light green color on the rim side. For Hbl, the brown part has more Al and Ti and lower #Mg than green ones. Their P-T conditions were estimated to 1.8-2.0 kbar and approximately 650-710 degree-C.