Geology of solar terrestrial planets is basalt, a denser volcanic rock that is the primary constituent of the ocean floors. Sedimentary rock is formed from the accumulation of sediment that becomes compacted together. Nearly 75% of the continental surfaces are covered by sedimentary rocks, although they form only about 5% of the crust. The third form of rock material found on Earth is metamorphic rock, which is created from the transformation of pre-existing rock types through high pressures, high temperatures, or both. The most abundant silicate minerals on the Earth's surface include quartz, the feldspars, amphibole, mica, pyroxene, and olivine. Common carbonate minerals include calcite
Chalcogen found in elemental form or in the form of sulfide minerals, sulfate minerals, or sulfosalt minerals. Stars of at least 12 times the mass of the sun produce sulfur in their cores via nuclear fusion. Sulfur is the tenth most abundant element in the universe, making up 500 parts per million of the universe by weight. Selenium makes up 0.05 parts per million of the earth's crust by weight. This makes it the 67th most abundant element in the earth's crust. Selenium makes up on average 5 parts per million of the soils. Seawater contains around 200 parts per trillion