Axia Week 5 Geology

Topics: Plate tectonics, Earth, Igneous rock Pages: 4 (1129 words) Published: December 3, 2011
Associate Program Material

History of Rock Worksheet

Write a 500- to 750-word explanation regarding the role of plate tectonics in the origin of igneous rocks.

| Plate tectonics play a major role in the origin of igneous rocks. Igneous rocks are called fire rocks and are formed either| |underground or above ground. Underground, they are formed when the melted rock, called magma, deep within the earth becomes trapped| |in small pockets. As these pockets of magma cool slowly underground,the magma becomes igneous rocks. Igneous rocks are also formed | |when volcanoes erupt, causing the magma to rise above the earth's surface. When magma appears above the earth, it is called lava. | |Igneous rocks are formed as the lava cools above ground. Rock formed of lava is called extrusive, rock from shallow magma is called| |intrusive and rock from deep magma is called plutonic. Igneous rocks form in three main places. They form where lithospheric plates| |pull apart at mid-ocean ridges, where plates come together at subduction zones and where continental crust is pushed together, | |making it thicker and allowing it to heat to melting. | |Most magmas are associated with plate tectonics. Basaltic and ultramafic magmas form along the divergent mid oceanic ridges and | |are major components of new oceanic crust. More felsic magmas, such as andesites and rhyolites, are associated with the edges of | |continental crust at subduction zones along converging plate boundaries. Whether a magma is intermediate or felsic may depend on | |the relative amounts of oceanic crust and continental crust in the subduction zone that melt to form the magma. The great abundance| |of granitic intrusions in continental crust is thought to be related to the partial melting of the lower continental crust.Plate | |tectonics is the study of how the Earth's plates are driven and shaped by geological...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • geology Essay
  • Axia Hhs 225 Answers Week 5 Essay
  • Essay on Geology 122
  • Geology Essay
  • week 5 Essay
  • week 5 Essay
  • Week 5 Assignment 5 Essay
  • week 5 Essay

Become a StudyMode Member

Sign Up - It's Free