The effects of the late Permian volcanism in Primorye are evident primarily along the southern margin of the Khanka Massif, a crystalline massif representing the extreme eastern block of the Sino-Korean Platform. Volcanism developed there under a variety of geodynamic conditions. In the western part of South Primorye, Upper Permian volcanics and associated terrigenous and carbonaceous rocks settled in the sea basin, which was formed through the destruction of the ancient sialic basement by the Hercynian orogenic movement. When that orogenesis was completed, that depression turned into a foldbelt, which is mapped as the West Primorye (or Khasan-Grodekovo) structuralfacies zone (Nazarenko and Bazhanov, 1987).

In the eastern part of South Primorye, Upper Permian volcanic rocks formed under the platform conditions directly on the area of the Khanka Massif in separate volcano-tectonic depressions. Their occurrence immediately on the ancient Precambrian rocks shows that they and accompanying terrigenous deposits belong to the complex of the platform mantle.

This chapter describes the structure and composition of the Upper Permian volcanogenic complex of South Primorye.

Position and structure of the volcanogenic complex

The Upper Permian volcanogenic formation is best studied in the West Primorye Fold Zone. It is a marginal eastern member of the meridional Laoelin-Grodekovo Depression, which wedges from the south to the Sino-Korean Platform, covering the adjacent territories in Korea and China (Smirnov, 1963). Deep faults outline the depression and separate it from ancient western and eastern crystalline massifs.