Lava low degree of polymerization and high temperature favors chemical diffusion, so it is common to see large, well-formed phenocrysts within mafic lavas. Basalt lavas tend to produce low-profile shield volcanoes or "flood basalt fields", because the fluidal lava flows for long distances from the vent. The thickness of a basalt lava, particularly on a low slope, may be much greater than the thickness of the moving lava flow at any one time, because basalt lavas may "inflate" by supply of lava beneath a solidified crust. Most basalt lavas are of "ʻAʻā" or "pāhoehoe" types, rather than block lavas. Underwater, they
Ice-marginal lava flow its subglacial beginnings. Currently the volcano is surrounded on all sides, except the south, by glaciers. What does Hoodoo mountain have to do with ice-marginal lava flows? Well, the entirety of the mountain is also surrounded by enormous lava cliffs, ranging from 50m-200m in height, as seen in Figure 3. The clearest example of these lava cliffs is seen on the southwestern side of the mountain whereas the northern formation of these cliffs has been overridden by recent lava flows and glacial erosion. Scientists are able to diagnose these lava cliff formations as a result of ice-marginal lava flows because