an ancient volcanic massif in the Western Sakhalin Mountains. It forms an outcrop on the western shore of the island of Sakhalin (Cape Lamanon).
The Lamanon Mountains consist of lava plateaus, with elevations of 300–800 m, composed of sheets of Miocene basalt and partly andesite, and a group of volcanic domes, 600–1,022 m in elevation (Mount Ichara). The volcanic domes are extrusive domes composed of Pliocene and post-Pliocene dacite and andesite. The neighboring Mount Krasnov (1,093 m), which is sometimes considered part of the Lamanon Mountains, forms such a dome. Streams of large blocks are found on the slopes. The mountains have a monsoon climate, with annual precipitation totaling 600–800 mm. Spruce and fir taiga and Erman’s birch with Kuril bamboo undergrowth are found on the slopes; Japanese stone pine grows near the summits. The Lamanon Mountains are named for Lamanon summit, which was named by the French navigator J. La Pérouse.