dacite

The Banzifang Formation, the main wall rock of veins I and II, is widespread in this area and consists of andesite, basaltic andesite, dacite, trachyandesite, andesitic volcanic breccia, and tufflava.

Main lithologies are a porphyritic dacite surrounded by a coarse-grained granodiorite.

Throughout the complex there are sills of gabbro, ultrabasic rocks and dacite porphyrite.

Three of the analysed samples from the latter formation contained > 63% Si[O.sub.2] (Appendix B), although only one of these plots in the rhyolite- dacite field based on immobile trace element ratios (Fig.lOa).

The lithology around CP is composed of gneiss (quartz-feldspars), shale (quartz-mica), marble, amphibolite, and quartzite from Permic to Jurassic [24] and metamorphic, granitic, and granodiorite rocks which are intruded by batholitic rocks [16], together with dacite and andesite from Miocene and rhyodacite from Quaternary [25].

The dominant geological parent materials of research area are rhyolite and dacite. In addition, basalt, claystone and limestone parent materials exist (URL, 2015).

This, similarity with a typical dacite from the Andes [9], and the Th/Yb vs.

--Neogene (Pliocene formations); covered the north watershed of basin, and appear as spot in middle basin, formed about 10.70 % of the total area, consist of gravel, sand, silt, pumice, and volcanic ash, with Augitehypersthene dacite welded tuff.

(1981) Geophysical characteristics of dacite volcanism--the 1977-1978 eruption of Usu volcano.