Liesegang Texture Found in Pyrophyllite Ore Deposits, Shobara district, Southwest Japan: Photograph collection

YAMASHITA Yoshiko

OHKAWA Makio

KITAGAWA Ryuji

TAKENO Setsuo

Journal of science of the Hiroshima University. Series C, Earth and planetary sciences

Liesegang textures are commonly occurred in pyrophyllite ore deposits in Shobara district, Southewest Japan. Color photographs of mode of occurrence, handspecimens and characteristic microtextures are presented. At the Sankin-motoyama outcrop, Liesegang texture is developed more than 500m long along the strike direction of the host rhyolitic rocks. The Liesegang texture is developed in the pyrophyllite rich zone and the texture is characterized by alternate of light and deep color bands. The light color is white to grey and the deep color is rather various such as brown, purple and grey. Two types of bands are recognizable, one is parallel and the other is perpendicular to the bedding plane of host rhyollitic rocks, respectively. The former is found in the marginal part whereas the latter mainly in the central part. Cylindrical Liesegang ring whose size is in the range from 10 to 50 cm is also common. The shape of the central core is various such as sphere, ellipsoid and cube. The band width of the Liesegang texture is various from few millimeters to several tens centimeters.
Under the microscope, double or triple hematite rings are commonly observed in the deep color part and towards the light color part, shape of the rings becomes more and more irregular. The boundary of light and deep color bands is clearly recognized under the microscope by sudden development of opaque minerals in the deep color part and the boundary is irregular compared with straight appearance observed in the out crop.
Detailed description of the texture will be appeared elsewhere.

eng

Hiroshima University

[ISSN] 0075-4374

[NCID] AA11095875