Rainbow Rocks


Rain pounds the ground. Streams turn into raging rivers. Floods race through a valley in ancient China. Water isn’t the only thing on the move. So


are sand, rocks, and dirt. T e water picks them up and moves them. It pushes specks of sand. It tumbles pebbles and even big boulders. T is movement is called erosion. Eventually, the water slows. T e sand and


rocks settle. Some fall to the bottom of lakes. Over time, more and more sand and rocks


pile up. T eir weight presses down. All this pressure glues the pieces together. T ey slowly turn into sedimentary rock. Sand turns into a rough kind of rock called


sandstone. Mud becomes mudstone. Pebbles turn into a bumpy rock called conglomerate.


T ese layers of rock remain hidden for a


long time. T en something happens. Earth’s tectonic plates shiſt . T ese giant plates make up Earth’s surface. T e ground heaves. In places, it rises. T is


upliſt pushes the hidden layers up. T e buried rocks rise higher and higher. T ey form many jagged peaks that tower over the land. Rain then pelts the rocks. Ice cracks them.


Sand whipped by winds scours them. T ese forces break the rocks into smaller pieces. T is process is called weathering. Today, in a desert in western China, the


mountains are gone. Wind and water have sculpted them into wavy hills. Iron streaks the rock red. Other streaks of blue, gray, and gold turn these rocks into rainbow rocks.


MARCH 2013 13 13


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