Volcanoes are natural laboratories in which ... The nature of their solid products, lava, scoria, lapilli, and ashes, have been carefully studied, but their gaseous products are less easily ...

In 2012, NASA's Mars Rover Curiosity photographed an outcrop with sedimentary structures resembling Earth's cross-bedded sandstones. The cross bedding, with large-scale layers sloping to the left, ...

These brick-shaped building blocks are known as Copperhouse slag or scoria blocks. This is a typical example. They were cast from the residue of the copper smelting works that operated at ...