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. The Ningyuancun Formation, the major host rock of vein III, is composed of tuff, rhyolite, and volcaniclastic rock.
However, in rare cases the pressure of the overlying water column may be high enough to produce tufflava (tuff-like/lava-like rocks) that contain evidence of heat retention (cf., Downey, 2005).
12 Pb-Zn deposits (New Brunswick), the presence of peperites in association with pyroclastic rocks and tufflavas indicates the in situ emplacement of pyroclastic rocks (cf., Downey, 2005).