Qias Gr

SW Sichuan next to Yunnan. The Qias Group was named by the No. 3 Team of the Party of Regional Geological Survey, Sichuan Bureau of Geology and Mineral Resources in 1984. The reference section is in Gaidongshan, Laohuili, Muli County, Sichuan Province.

Synonym: （恰斯群）

In the reference section, it has five parts (equivalent to formations). Those in the lower part of the group is dominated by metamorphosed volcanic rock, grading upward to metamorphosed clastic rock. Lower part (equivalent to Lixuewei Fm) is composed of greyish, grey-green biotite albite schist, two-mica quartz schist intercalated with albite-leucoleptite, with laminated structures (the protolith was basic volcanic rock, sandwiched with intermediate volcanic rock) (788 m thick). Lower-Middle part (equivalent to Panzhangting Fm) consists greyish, grey-green albite leucoleptite, albite two-mica schist (496 m thick), replaced upwards by grey-green garnet-actinolite albite schist, leucoleptite with grey, greyish and grey-white dolomitic quartzite (554 m), with the upper part being interbedding of light and dark banded metamorphosed intermediate acid volcanic rock with basalt. Middle part (equivalent to Gaidongshan Fm) is greyish grey-white albite leucoleptite sandwiched with greyish-green albite schist (serving as key bed for the group) (331 m). Upper-Middle part (equivalent to Erzuiqiang Fm) is composed of unequal thick-bedded interbedding of dark-green, green-grey, dark grey, garnet-mica albite schist with greyish white muscovite quartz (or albite) schist, sandwiched with quartzite and marble (464–474 m thick). Upper part of the group (equivalent to Zangka Fm) has uneven interbedding of greyish quartzite, light green and dark-grey, garnet-mica-albite schist and albite-quartz schist, sandwiched with grey-black carbonaceous cordierite phyllite which contains microplants (203 m thick). The total thickness of the Group is cited as 4000 m.

Trachysphaeridium, Leiopsophosphaera etc