A lava coil is a spiral or scroll-shaped lava formation occurring when relatively low viscosity lava such as Pahoehoe solidifies along a slow-moving shear zone in the flow. The shear produces a Kelvin–Helmholtz instability that forms spiral-shaped patterns. Depending on the side of the flow the spiral is clockwise or anti-clockwise. They have been observed on flows near Kilauea on Hawai'i,Dallas Peck, Lava coils of some recent historic flows, Hawaii. Geological Survey Research, B148-B151 1966 in KenyaTemperley BN (1966) Vortex exudation coils on a recent basaltic lava in Kenya. Overseas Geol Mineral. Resour. 10:42-46 and possibly on Mars.
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