Longmen Mountain of the Wudalianchi

Longmen Mountain of the Wudalianchi

West Longmen Mountain and East Longmen Mountain are located in the eastern part of the volcanic group, about 150 meters apart. They resemble a pair of twin sisters, accompanying and complementing each other, forming a distinct double-mountain structure in terms of terrain, with well-preserved volcanic cones.

East Longmen Mountain is located 6 kilometers southwest of Morabu Mountain. The basement of East and West Longmen Mountains is a basaltic shield highland that forms the Longmen Stone Pond. It has an elevation of 572 meters, a relative height of 151.4 meters, an overflow vent facing southeast, a cone base diameter of 900 meters, a crater depth of 101 meters, and an inner crater diameter of 380 meters. The cone is composed of black pumice, with purplish-red blocky lava at the top.

East Longmen Mountain is covered with trees, with slopes inclined at around 30 degrees. The crater wall is horseshoe-shaped, higher on the northwest side and descending toward the southeast. The southeast side is about 100 meters lower than the northwest side, and the crater is oval in shape. This mountain has a volume of 0.046 cubic kilometers, making it the largest among the eastern volcanoes. The eastern foot of the volcanic mound has a diameter of 80 meters and features a circular basin-like depression, with edges about 2 meters high and a flat bottom.

West Longmen Mountain has an elevation of 581.4 meters, with an overflow vent facing southeast. The cone slope ranges from 25° to 40°, the base diameter is 900 meters, the crater depth is 134 meters, the inner crater diameter is 300 meters, and the relative height is 156 meters. The cone is mainly composed of red pumice, with the southern part consisting of black basalt.

West Longmen Mountain is almost entirely covered with trees, except for the grassy slope on the southwest side. It features a variety of trees including poplar, birch, maple, and linden. The crater wall is oval, higher in the northwest and lower in the southeast, with a flat bottom scattered with rock fragments. About 200 meters southeast of the crater lies a shallow crater flow, separating it from a parasitic crater with a height difference of about 60 meters on either side—forming what resembles part of an outer ring mountain.

Basalt, the main component of oceanic crust, is a basic volcanic rock. It is the primary material composing the Earth's oceanic crust and the lunar maria, as well as an important constituent of the Earth's continental crust and lunar highlands.

Basalt is a basic extrusive rock, chemically similar to gabbro or diabase. Its mineral composition mainly consists of basic feldspar and pyroxene, with minor minerals such as olivine, amphibole, and biotite. The rock is generally dark in color, typically black, though sometimes appearing gray-green or dark purple. It exhibits a porphyritic texture, with common vesicular and amygdaloidal structures.