They would most likely be metamorphic. "Lava" refers to magma (molten rock) that has reached the surface, igneous rock is sourced from magma and lava, and sedimentary rocks are formed at the Earth's surface.
World's Top 10 Toxic Pollution Problems
Lead-Acid Battery Recycling. ...
Mercury and Lead Pollution from Mining. ...
Coal Mining (Sulphur Dioxide and Mercury Pollution) ...
Artisanal Gold Mining (Mercury Pollution) ...
Lead Smelting. ...
Pesticides Pollution from Agriculture and Storage. ...
Arsenic in Ground Water. ...
Industrial Waste Water.
Or <span>The average density of the boat, including the steel and air, is less dense than 1.00 g/cm³..</span>