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,
Liquid chalk Liquid chalk The term liquid chalk refers to several different kinds of chalk: Despite the term, some forms of "liquid chalk" contain no actual chalk. Liquid chalk can be a variation of normal chalk (see: magnesium carbonate) used to improve grip for sports, such as rock climbing, weight lifting, or gymnastics. Rock climbers use liquid chalk to prevent their hands from sweating. It may be used by climbers in situations where powdered chalk is restricted. It is preferred by athletes because it remains effective longer and leaves less residue on rocks and equipment. Liquid chalk for rock climbers is made