Joint visit of Canadian and Soviet scientists to the northeastern Soviet Union¹

Geology of Wrangel Island, between Chukchi and East Siberian seas, northeastern Russia

“…Devonian strata of northern Chukotka Peninsula are similar in facies and composition to the Devonian sandstone and slate strata of Wrangel island (Kos'ko et al, 1990;Cecile et al, 1991b). On the New Siberian Islands, and on the northeast tip of Chukotka, Devonian strata are a mixture of clastic rocks and carbonate (Rogozov and Vasil'eva, 1968;Oradovskaya, 1971, Oradovskaya andObut, 1977;Kos'ko et al, 1990).…”

“…The presently accepted limit of the Arctic Alaska-Chukotka Ancestral Plate, which is tectonically linked to the Canada Basin area, is defined by a discontinuously exposed belt of obducted lower Mesozoic ultramafic rocks (partial ophiolites) that outcrop in the southern Brooks Range of Alaska (Boak et al, 1987;Loney and Himmelberg, 1989) and the South Anyui Suture Zone of the western Chukotka Peninsula ( Fig. 5;Seslavinsky, 1979;Cecile et al, 1991b). North of these two ultramafic rock zones there is evidence of continuity of structure and stratigraphy between the Brooks Range, the subsurface of the Alaskan North Slope, and the land and shelf areas of the Chukchi and East Siberian seas as far west as, and including, the New Siberian Islands (Grantz et al, 1981).…”

“…A granite of pre-Early Carboniferous age is known from Cape Kiber (Fig. 1), on the northern coast of the Chukotka Peninsula (Cecile et al, 1991b). Kos'ko et al (1990) have hypothesized a Late Proterozoic age for melanocratic schists and gabbros of southeastern Bol'shoi Lyakov Island in the New Siberian Islands (Fig.…”

“…A granite intrusive of assumed early Paleozoic age ("pre-Lower Carboniferous") outcrops to the east of Pevek ( Fig. 1; Kos'ko et al, 1990;Cecile et al, 1991b). In a tabulation of K-Ar dates from northeastern Chukotka, Shilo and Zagruzina (1965) and Gnibidenko (1969) reported the following Early Ordovician through Early Silurian ages: 430 Ma from quartzbiotite slate; 432 Ma from a granite gneiss; and 502 Ma from a granite gneiss.…”

“…In northern Chukotka similar depositional facies are present. Lower Carboniferous limestones, with locally derived, coarse, sedimentaryclast conglomerate are known from at least two locations on the mainland south of Wrangel Island (Cecile et al, 1991b). In one of these occurrences (Cape Kiber area, Fig.…”