1. Igneous Rock Features (41) More activity occurs underground Most magma never reaches Earth’s surface. Produces underground rock bodies that could become exposed

2. Rock bodies are called intrusive igneous rock features. The most common are batholiths, sills, dikes, and volcanic necks.

3. Largest intrusive igneous rock bodies are batholiths. Can be hundreds of kilometers in width and length and several kilometers thick. Form when magma bodies being forced upward inside Earth cool slowly and solidify before reaching the surface. http://www.youtube.com/ watch?v=6a2-uEZZEG0http://www.youtube.com/ watch?v=6a2-uEZZEG0

4. Some batholiths have been exposed at Earth’s surface by many millions of years of erosion. The granite domes of Yosemite National Park are the remains of a huge batholith that stretches across much of the length of California.

5. Dikes and Sills Magma sometimes squeezes into cracks in rock below the surface. When this cuts across rock layers and hardens, it is called a dike. Magma that is forced into a crack parallel to rock layers and hardens is called a sill http://www.youtube.com/watch?v=6loGYTCBVqo

6. Volcanic Neck When a volcano stops erupting, the magma hardens inside the vent. Erosion wears away the volcano. Leaving behind the solid igneous core as a volcanic neck

7. Calderas Sometimes after an eruption, the top of a volcano can collapse. This produces a large depression called a caldera

8. Magma that has hardened in a crack parallel to rock layers is a __________. A. Batholith B. dike C. neck D. sill

9. What is a batholith? Batholiths, like dikes and sills, are intrusive igneous rock features. They form when magma cools slowly underground without reaching Earth’s surface. Batholiths are the largest of the intrusive igneous rock bodies.

10. What is the difference between a volcanic crater and a caldera? Both craters and calderas are steep-walled depressions around a volcano’s vent. A caldera is a large depression produced by the collapse of the top of a volcano. http://video.pbs.org/video/2182459039