Abstract
Carbonaceous material in pelitic rocks and limestones of the Ayukawa and the Daioin Formations in the Hitachi metamorphic rocks was investigated by means of X-ray powder diffraction technique. Carbonaceous material in these metasediments was graphitized under the conditions of greenschist facies. rystallite thickness Lc (002) ranges from 29 to 170 Å in the Ayukawa Formation and that from 120 to 300 Å in the Daioin Formation.
Lc (002) of carbonaceous material in pelitic rocks containing biotite is more than 60 Å and increases with increasing metamorphic grade. Lc (002) value at a boundary between greenschist and epidote-amphibolite facies may be estimated 260-300 Å from the data of Lc (002) of the lower part of the Daioin Formation.
Lc (002) of the Ayukawa Formation surrounding the sheared granite is above 200 Å. As compared with the general value of the Daioin Formation, Lc (002) of the Daioin Formation around the sheared granite is not so high. Thermal effect of the sheared granite was not marked, which suggests that the sheared granite intruded under low temperature condition.
