SOUTHWESTERN PRIMORYE AS THE EASTERNMOST SEGMENT OF THE SOLONKER COLLISION ZONE

Here we report the results of the distribution analysis of floristic remains from the Angara and Catasian paleobiogeographic regions in Permian deposits of southwestern Primorye. It is shown that the early-middle Permian stratigraphic units (Dounay, Pospelovska and Abrek formations) along the southern margin of the Songen-Bureya-Jiamusi-Khanka continental block contain floristic complexes of the Angara type, and no other. Their age equivalents (Kazachka and Reshetnikovka formations) in the Laoelin-Grodekovo terrane, a fragment of the Permian intraoceanic island-arc system, are characterized by a mixed composition of floristic complexes including representatives of both the Catasian and Angara paleobiogeographic regions. The first representatives of the Catasian flora found in deposits of the Dvoryansky terrane (Vladivostok Formation) were Middle Permian in age. Their number was significantly up by the beginning of the Late Permian. Both types of flora are assumed to spread in opposite directions across the volcanic islands of the island arc system located between the converging Amur continental block and the North China Craton during the closure of the Central Asian Ocean.