ABSTRACT: Metallogenic Features of the Olistostrome Assemblage, Sikhote-Alin Fold Area

A. A. Vrublevsky, L. A. Izosov, Y. P. Yushmanov, N. A. Vrublevskaya

The olistostrome formation of Upper Jurassic-Lower Cretaceous age occurs on vast areas within the Khabarovsk and Primorie regions; it has volcanogenic-carbonate-siliceous-terrigenous composition. In the Primorie region it encompasses (1) industrial tungsten deposits of sheelite-pyrite type, (2) industrial scarn deposits of polymetals, and (3) copper-pyrite and pyrite-polymetallic occurrences.

The specific features of the upper Jurassic-Lower Cretaceous olistostrome assemblages are as follows: (l) arkose-graywacke composition of its terrigenous rocks, (2) considerable quantities of carbonaceous (black) schists, and (3) predominance of basaltoids of sodium and potassium-sodium type in the volcanites. Often, the rocks of this formation are characterized by increased content of copper, polymetals, arsenic, bismuth, and precious metals. In the black schists, there often occur interbeds rich in sulfides that are indicative of the formation's great perspectives regarding pyrite ore mineralization. Thus, the Upper Jurassic-Lower Cretaceous olistostrome is ore-bearing and is an object of extensive prospecting.

The olistostrome thick unit is an indicator of great thrust motions. The Late Jurassic-Early Cretaceous stage of East Asia development is generally known for its intensive tectonic activity.

It is remarkable that on the Japanese Islands, similar in their lithology and age assemblages, there were ascertained numerous industrial pyrite deposits. Comparative analysis of the Upper Jurassic-Lower Cretaceous thick units of the Japan Sea region enables us to expect discovery of industrial pyrite deposits in the Primorie and of tungsten sheelite-pyrite ores in Japan.

AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990