To prove his hypothesis Hutton and two other scientists traveled by boat down the coast of Scotland hunting for rocks to tell the story At Siccar Point on the North Sea the men found a unique formation At the bottom was gray layered rock like a layered birthday cake But the layers of this rock had been turned on their sides They stood straight up and down Siccar Point is now considered the most important geological location in the world 6
To Hutton this proved that powerful forces had made the layers crash turn and shoot up out of the ocean where they had formed On top of the vertical rocks was another slab of gray rock and then another layer of newer red rock Since Hutton knew how long it took mud to build up in rivers he concluded Siccar Point must have taken hundreds of thousands of years to form Hutton published his findings in the 1780s Scientists of the day were slow to accept his ideas especially his suggestion that Earth was very old Today Hutton’s theories are the basis of the study of geology Many experts consider him the father of geology and the rock cycle Geological Time Rock layers called strata are used by scientists to determine the relative ages of events and objects in Earth’s history The Permian through Jurassic strata in the Colorado Plateau area of southeastern Utah show how scientists represent Earth’s geologic time vertically since new rock can only be laid upon older rock 7
RECYCLING ROCKS As Hutton discovered rocks are not created from nothing nor ever completely destroyed Instead they are recycled over and over again through a process called the rock cycle Think of rocks as glass jars When you send an empty jar to a recycling factory the glass is crushed into little pieces Then it’s melted down and poured into molds to harden and form new containers The glass is not created nor destroyed during the process it just changes form The rock cycle works in much the same way Rain wind and other forces wear down old rocks The rock fragments are deposited in layers by wind and water over long periods of time The weight of 8
There are three basic types of sedimentary rocks clastic chemical and organic many layers squeezes them and cements them together creating sedimentary rocks Through heat and pressure the chemical makeup of any rock can change These are called metamorphic rocks If the rock melts during the process it becomes the raw material for igneous rock These are rocks that form magma or molten rock Rockin Makeovers The name for metamorphic rocks comes from the word metamorphosis It means a complete change in appearance or makeup Metamorphosis happens at temperatures between 480 degrees Fahrenheit 250 degrees Celsius and 1,290 degrees Fahrenheit 700 degrees Celsius At those temperatures the rocks do not melt 9
