Geological Gallery

Continental drift, 100 million years ago

Continental drift, 100 million years ago. Map of the Earth showing the continents some 100 million years after the start of the break-up of the ancient supercontinent of Pangea, and 100 million years before the modern era. The Earth's continents move over the surface of the Earth, driven by movements of the fluid mantle below the crust. This stage in the history shows the emerging shapes of some of today's continents. It will take another 350 million years from this point before the next supercontinent, Pangea Ultima, forms

© MIKKEL JUUL JENSEN / SCIENCE PHOTO LIBRARY

Krakatoa sunsets, 1883 artworks

Krakatoa sunsets. Artwork of the spectacular red and orange sunsets caused in London, England, by the August 1883 eruption of Krakatoa, a volcano thousands of kilometres away in Indonesia. The ash thrown up by the eruption caused sunsets like these for years afterwards. These three artworks are a sequence, showing twilight and afterglow effects at Chelsea, London, on 26 November 1883, at around: 4.40pm (top); 5pm (middle); and 6.15pm (bottom). These are among the thousands of sunset sketches made by the British artist William Ashcroft. Krakatoa's eruption prompted many reports and investigations. These artworks formed the frontispiece for The Report of the Krakatoa Committee of the Royal Society (1888)

© ROYAL ASTRONOMICAL SOCIETY/SCIENCE PHOTO LIBRARY

Mariner 10 mosaic of Mercury

Mercury. Mariner 10 spacecraft mosaic image of Mercury, the closest planet to the Sun. Areas for which data is missing are blank. The surface of Mercury is heavily cratered due to impacts from meteorites. It also has lines of cliffs which are up to 3 kilometres (km) high and 500 km long. These escarpments may have been formed by the planet's crust wrinkling as the core cooled and contracted billions of years ago. The surface rocks are generally dark and a poor reflector of sunlight. Mercury has about the density as Earth, though it has only about 5% of the volume and mass of our planet. The Mariner 10 spacecraft imaged Mercury on three flybys during 1974-75

© US GEOLOGICAL SURVEY/SCIENCE PHOTO LIBRARY