Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two...

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Igneous Rock Features Chapter 12, Section 3

Transcript of Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two...

Page 1: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Igneous Rock FeaturesChapter 12, Section 3

Page 2: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Classification Igneous rocks are classified into two areas

depending on where thy formed. Intrusions

Underground igneous rock masses.

Extrusions Above ground igneous rock masses.

Page 3: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Extrusive Features Include volcanoes, flood basalts, lava flows,

etc.

Page 4: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Intrusive Features Form when magma cools and hardens

underground. These structures may later be exposed at the

surface through erosion. Include:

Batholiths, dikes, sills, and volcanic necks.

Page 5: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Intrusive Features Batholiths

Largest intrusive structures. Cover over 100 square kilometers.

May be many hundreds of kilometers in width and length and several kilometers thick.

Tend to form the cores of major mountain ranges.

Page 6: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Example: Boulder Batholith

Page 7: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Intrusive Features Stock

Similar to a batholith, but… Covers less then 100 square kilometers.

Page 8: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Intrusive Features Laccolith

Forms when magma flows between rock layers and spreads upward, pushing the overlying rock layers into an arc.

The floor of a laccolith is parallel to the rock layer beneath it.

Page 9: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Intrusive Features Dike

Forms when magma that has been forced into a crack that cuts across rock layers hardens.

Page 10: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Intrusive Features Sill

Forms when magma that has been forced into a crack running parallel to rock layers hardens.

Page 11: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Volcanic Neck Forms when the magma inside a volcano

cools and hardens and the overlaying softer layers are eroded.

Page 12: Igneous Rock Features Chapter 12, Section 3. Classification Igneous rocks are classified into two areas depending on where thy formed. Intrusions Underground.

Calderas Form when the top of a volcano collapses into

an emptied magma chamber. Example – Crater Lake – Formed after the

eruption of Mount Mazama around 7,000 years ago.