Igneous rocks close igneous rockIgneous rocks are those which have been formed by the cooling and solidification of molten rock (magma) from underneath the earth’s crust. are formed by magma ...

Volcanoes are cracks in Earth's crust that allow molten rock and hot gases to escape ... that probably won't ever erupt again. 5 fast facts about volcanoes Volcanic ash is made of fragments ...

What Was Happening on Earth at This Time The Precambrian is the earliest of the geologic ages, which are marked by different layers of sedimentary rock. Laid down over millions of years ...