Lava field lavas of at least . The lavas are thought to have originated from a mantle plume center called the Mackenzie hotspot. Lava field A lava field, also called a lava plain or lava bed, is a large expanse of nearly flat-lying lava flows. Such features are generally composed of highly fluid basalt lava, and can extend for tens or even hundreds of miles across the underlying terrain. The extent of large lava fields is most readily grasped from the air or in satellite photos, where their typically dark, nearly black color contrasts sharply with the rest of the landscape. According
Joint (geology) a distinctive type of joints that join together at triple junctions either at or about 120° angles. These joints split a rock body into long, prisms or columns. Typically, such columns are hexagonal, although 3-, 4-, 5- and 7-sided columns are relatively common. The diameter of these prismatic columns range from a few centimeters to several metres. They are often oriented perpendicular to either the upper surface and base of lava flows and the contact of the tabular igneous bodies with the surrounding rock. This type of jointing is typical of thick lava flows and shallow dikes and sills. Columnar