Petrology and P-T conditions of stilpnomelane schist in the Yilan district, Heilongjian Province.

Stilpnomelane schist contains mineral assemblage of stilpnomelane + chlorite + phengite + albite + tremolite + quartz + K-feldspar ±biotite in Heilongjian complex, Yilan district. Mineralogical and petrological studies show that stilpnomelane schist formed under P-T conditions of 250～400℃ and 6～9kbar. Brown stilpnomelane occurs in the form of fascicular or radial aggregates. Stilpnomelane schist was formed in the process of Jiamusi block westward subduction with Songnen block during post-stage blueschist metamorphism, and was a product of geological deformation environment with pressure slightly decline and temperature slightly increase when blueschist facies transforms into greenschist facies.