The Middle Proterozoic Xiong er subvolcanic rocks are widely loucated in Xiong er Group volcanic rocks and the metamorphic basement near the bottom of Xiong er Group.

• 熊耳期次火山岩广泛分布于熊耳群火山岩及接近熊耳群底部的基底变质岩系中,活动时间贯穿整个熊耳期,以早期和晚期最为发育。