Shield volcano are cave-like volcanic straights formed by the hardening of overlaying lava. These structures help further the propagation of lava, as the walls of the tube insulates the lava within. Lava tubes can account for a large portion of shield volcano activity; for example, an estimated 58% of the lava forming Kīlauea comes from lava tubes. In some shield volcano eruptions, basaltic lava pours out of a long fissure instead of a central vent, and shrouds the countryside with a long band of volcanic material in the form of a broad plateau. Plateaus of this type exist in Iceland, Washington, Oregon,
Zuidwal volcano mineral composition, points to volcanic activity as a result of subduction far away from the volcano. During the Cimmerian Orogeny, the Cimmerian Plate collided with Kazakhstania, sending shock waves through the Eurasian Plate, resulting in volcanism. The volcano is covered by layers of sandstone from the early Cretaceous that act as reservoir rock for the gas. The seal rock consists of shale. The volcanic rock is magnetic, creating a magnetic anomaly. Zuidwal volcano The Zuidwal volcano is an extinct volcano in the Netherlands at more than below ground under the Wadden Sea, between Harlingen and Vlieland, just south west of