Dzhugdzhur

mountains along the northwest coast of the Sea of Okhotsk, in Khabarovsk Krai, RSFSR. They extend in a gentle sloping convex arc for 700 km. Heights of 800 to 1,200 m predominate, Mt. Topko being the highest point at 1,906 m.

The Dzhugdzhur Mountains were formed by a recent asymmetric upheaval. The gently sloping continental grade of the Aldan River basin sharply differs from the deeply dissected slopes of the Sea of Okhotsk. In the southwest part of the arc, gneisses and granites of the late Precambrian have surfaced. In the northeast shale and limestone, crushed in the Mesozoic, are covered by a thick layer of lava and tuffs from the Cretaceous and Paleocene periods. The broken chain of coastal mountains, separated lengthwise by the Ul’ia River valley, are very damp. The climate is moderately cold, with monsoons and a severe winter. Along the coast, washed by the cold waters of the sea, there are growths of Japanese stone pine. The Okhotsk mountain taiga with Yeddo spruce is found on coastal slopes up to heights of 1,300 m. On the Aldan grade, there is a light-colored coniferous taiga with Dahurian larch. There are growths of Japanese stone pine in the zone near the crests. The jagged peaks, evidence of ancient glaciation, are covered with mountain tundra.