Which came first, igneous, metamorphic, or sedimentary rock?

• What does the word “metamorphic” mean?
• What does this imply about when it could have formed, compared with other rock types?
• Sediment is small pieces of broken rock that have fallen to the bottom of moving streams. T/F
  

The earth’s original surface could have been composed of sedimentary rocks, but only when the planet was forming. As these smaller pieces of space material accumulated into the planet, all of these materials melted and combined into the earth’s original sphere.

• Considering that smaller pieces of space dust melted to form the earth, which rock type seems most likely to have formed first? 

Step 1: Go to the ArcGIS Online map, Rock Types Tell Stories, and explore the map.

Step 2: Click “Modify Map.”

Step 3: Click the “Igneous Plutonic” area of the map.

Step 4: Click the “Igneous Volcanic” area of the map to see several of the rocks formed from lava. Compare and contrast the plutonic rocks and volcanic rocks.

Earth’s crust over geologic time.

Step 5: Click the “Contents” button. Turn off the “NA Rock Types” layer, and look at the ruggedness of the country.

• Which area has the newest, most recently crumpled surface?
• What happens as an older, lower, and more worn or eroded set of mountains? (Select all that apply.)