rock formations Flashcards
how is basalt formed
formed when lava spreads over the surface of the earths crust due to volcanic activity.it cools and hardens. It has tiny crystals which cannot be seen because it cooled very quickly in the open air
how is granite formed
formed when magma pushes its way to the crust and cools and hardens under the surface. It has large crystals as it cools very slowly over millions of years.
how is limestone formed
it is made of particles of shells and the remains of skeletons of sea creatures. when these particles sink to the bottom of the surface they are called sediment. This piles up over millions of years and is compressed and cemented. limestone is permeable and soluble.
how is sandstone formed
formed from sand that has been worn away from the surface. this sand is carried by wind and rivers and deposited as sediment and layers build up over time. The layers are compressed and cemented together to form sandstone.
how is marble formed
formed when limestone comes under great heat or pressure due to plate movement or when molten magma comes into contact with it.
how is quartzite formed
formed when sandstone is put under great heat or pressure due to plate movement or when molten magma comes into contact with it.
