THE thickness of a lava flow depends, in general, on three factors: the viscosity of the flowing lava; the angle of slope of the surface over which the lava is flowing; the local topography ...

“And the lavas did something that no other lava flows on Earth have done. Geologists call it differentiated: The rock changed ...

(Courtesy U.S. Geological Survey) The lava flow caused by the Midcontinent Rift ... Keweenaw basalt is a middle layer of pegmatoids, a type of igneous rock with notably coarse grains that produce ...