Verkhoiansk Range

a highland in the northeastern Yakut ASSR. It is formed by numerous mountain ranges and massifs and the hollows that separate them. The Lena-Iana-Omoloi watershed runs along the Verkhoiansk Range, which stretches 1,200 km from the Lena delta to the Tompo River (a right tributary of the Aldan), forming a bow that bulges to the southwest and varies in width from 100 to 250 km. The southeastern extension of the Verkhoiansk Range is known as the Sette-Daban Range; it is distinguished by different relief and geological structure. The northern end of the Verkhoiansk Range is formed by the Tuora-Sis and Kharaulakh ranges, with elevations less than 1,000-1,250 m. The meridional section of the mountainous area—the Orulgan Range—is formed of the highest ridges of the Verkhoiansk Range, with elevations of 2,100-2,300 m; the highest point is 2,389 m. The long, narrow Kular Range, with elevations to 1,300 m, branches off eastward of the Orulgan Range. In the longitudinal section of the Verkhoiansk Range, the mountain peaks exceed 2,000 m in elevation. Anticlinal passes in the primarily mountainous area are at elevations of 1,300-1,500 m. The river valleys on the western and southern slopes are deep, with traces of glaciation; amphitheaters of terminal moraines are observed at their outlets onto the plain. The peaks of the ridges often have sharp, alpide relief forms. At the summits of ridges and massifs there are sizable areas of ancient leveled terrain; these have been better preserved in the lana basin. Tectonically the Verkhoiansk Range is an anticlinorium composed of aleurolites, sandstones, shales, and—less frequently—limestones (the Verkhoiansk complex). Sedimentary rocks are faulted in places with diabasic dikes as well as granite intrusions, with which deposits of gold and tin are associated.

The climate is cold and sharply continental. Temperature inversions are typical during the long winter; they are particularly sharp in the foothills, basins, and large river valleys. The average January temperature is -36° to -38° C. The summers are short and comparatively warm (average July temperature 12°-14° C) in the valleys of the south. Almost three-quarters of the total annual precipitation falls in the summer, with the greatest quantity—up to 600 mm per year—falling on the western slopes of the Orulgan Range. Perennially frozen rocks are prevalent everywhere; the formation of layers of ice is associated with them.

The summits of the highest mountain ridges are areas of cold Arctic desert. Farther down on the slopes, on rubbish and sandy loam soils, shabby mountain-tundra flora appears; still lower the flora changes to thickets of Japanese stone pine, creeping birch, Manchurian alder, and polar willow. In the south, the lower portions of mountain slopes (up to elevations of 800-1,200 m) are covered with sparse larch forests. There are many steppelike areas on slopes with southern exposures. Woods formed of pine, birch, and rarely spruce; groves of Mongolian poplar; and thickets of shrubs—in addition to larch forests—are encountered on the alluvial podzolized soils of the bottoms of the large river valleys.