The document describes two types of endogenous (internally driven) landform-building processes: igneous and tectonic processes. Igneous processes create landforms such as volcanoes through volcanic eruptions and igneous intrusions. Tectonic processes like folding, faulting, and lateral faulting form landforms including mountains, rift valleys, escarpments, and are responsible for earthquakes through ongoing tectonic activity.

1. A. Endogenous Processes
Endogenous Processes are large-scale landform
building and transforming processes
– they create relief.
1. Igneous Processes
a. Volcanism: Volcanic eruptions  Volcanoes
b. Plutonism: Igneous intrusions
2. Tectonic Processes (Also called Diastrophism)
a. Folding: anticlines, synclines, mountains
b. Faulting: rift valleys, graben, escarpments
c. Lateral Faulting: strike-slip faults
Earthquakes  evidence of present-day tectonic activity

3. Granite quarry
What
important
natural
resources are
found in
igneous
rock?

4. Steven Earle
Stawamus Chief, Squamish BC
Massive granite
Mafic dyke
(~5 m across)

5. Igneous Rock
 Igneous rock is formed when molten, or partially molten, rock
solidifies.

6. Igneous Rocks (two types)
 Extrusive
 Lava and Pyroclastic Debris
 Extruded at surface or at very
 shallow levels and cooled quickly
 Intrusive
 Magma crystallized slowly within
the crust.
 No exposure to the cool
atmosphere.
 Plutonic – intrusive igneous rock
cooled slowly at great depth
within crust or mantle.
Basalt is
Extrusive
Granite is
Intrusive
What is the key textural difference between these two rocks?

7. Why Study Igneous Rocks?
 All rocks on Earth have evolved from the first igneous
rocks through Igneous Evolution
 Provide information about the composition of the
mantle
 Absolute age can be obtained through Radiometric
Dating
 Features are characteristic of a specific tectonic
environment
 Host important mineral deposits (metal ores)
 Numerous other critical economic uses
 Millions of people are endangered by volcanoes

8. Decompression melting
 Convection brings hot rock
to shallower depths
 Rifting lowers pressure
 Lower pressure causes a
lower melting point
 Igneous rock is formed
through a process of
crystallization and magma
differentiation
Why does a lower pressure lower the melting point?

9. Partial Melting
 Partial Melting
 Silica-rich compounds melt before
other compounds.
 Magma Differentiation
 Four types:
 Magma mixing
 Crystal settling
 Wall-rock assimilation
 Magma migration

10. Bowen’s Reaction Series
• Describes the order and process of magma crystallization
Bowen’s Reaction
Series Animation

11. How Are Igneous Rocks Named?
 Texture
 Texture depends on crystal size
A. Phaneritic:
 Slow cooling (or in the presence of water), larger
crystals, Coarse texture, Intrusive or Plutonic
B. Aphanitic:
 Rapid cooling , smaller crystals, Finer texture,
Extrusive or Volcanic
C. Other textures are Glassy, Pyroclastic, Vesicular, and
Porphyritic
 Composition
 Minerals at the TOP of Bowen’s
 Dark in color
 Mafic to Ultramafic

12. How Are Igneous Rocks Named?
Composition
 Minerals at the TOP of Bowen’s
 Dark in color
 Mafic to Ultramafic
 Iron and Magnesium are dark.
 Minerals at the BOTTOM of Bowen’s
 Light in color
 Felsic
 Sodium plagioclase, potassium plagioclase,
and quartz are light
 Intermediate composition between these

13. How is Texture Estimated?
• Texture is estimated
using visual grain size
• (depends on
crystallization history)
What has to happen for a porphyritic texture to form in an
igneous rock?

14. How is Composition Estimated?
 Composition is estimated using visual color
 Can be misleading

15. Classification System for Igneous
Rocks
 The classification system for igneous rocks is
based on the following:
 Intrusive and extrusive igneous rocks with the
same chemical composition contain the same
minerals
 Silica content decreases as iron and magnesium
content increases
 Potassium and sodium content decreases as silica
content decreases

16. Seven Common Types of Igneous
Rock
1) Granite
intrusive
2) Rhyolite
extrusive
Felsic Composition

17. Seven Common Types of Igneous
Rock
3) Diorite
intrusive
4) Andesite
extrusive
Intermediate
Composition

18. Seven Common Types of Igneous
Rock
Mafic Composition
5) Gabbro
intrusive
6) Basalt
extrusive

19. Seven Common Types of Igneous
Rock
Ultramafic Composition
7)
Peridotite
intrusive

20. Igneous Evolution
 All rocks on Earth have evolved from the first igneous rocks
 All Igneous Rocks Result from Magma Differentiation

21. Tectonic
Processes

22. Tectonic Processes
 Igneous rock evolves as a product of tectonic processes and is a
major component of Earth’s crust
What is the mechanism that leads to partial melting above a subductio

23. Identify the magma source for each type of volcano. How is the
magma source responsible for the rock composition?

24. Basalt Formation (Spreading
Centers)
 High heat flow creates Hydrothermal (hot water) Vents
(black smokers)
 Oceanic crust consists of layers of igneous rock
 Gabbro crystallizes at the base
 Sheeted dikes of basalt extend above the gabbro
 Pillow basalt, glassy fragments and metallic sulfide deposits
(at black smokers) form at the sea floor

25. Basalt Formation (Hot Spots)
 Intraplate sites of active Plutonism
and Volcanism
 Large Igneous Provinces of Flood
Basalts form above mantle hot spots
 Plumes of anomalously hot mantle
rock underly active hot spots.
Mantle plumes, which are solid rock,
not magma, rise slowly through the
mantle (but faster than the rate of
mantle convection) due to their
positive buoyancy with respect to
the surrounding rock.
 Basalt is also present at many
subduction-related volcanoes, but
typically only in minor amounts.

26. Modern sea-floor pillow basalt
pillow basalt on
Vancouver Island
Steven Earle

27. Igneous Intrusions
• Igneous intrusions occur in a variety of sizes and shapes.

28. Subduction Zones and Spreading
Centre
 Subduction zones and spreading centers are areas in which
magma is formed as a result of partial melting, plutonism, and
volcanism.
What igneous environment is not represented in this image?

29. COPYRIGHT
Copyright © 2014 John Wiley & Sons Canada, Ltd. All
rights reserved. Reproduction or translation of this
work beyond that permitted by Access Copyright (The
Canadian Copyright Licensing Agency) is unlawful.
Requests for further information should be addressed
to the Permissions Department, John Wiley & Sons
Canada, Ltd. The purchaser may make back-up copies
for his or her own use only and not for distribution or
resale. The author and the publisher assume no
responsibility for errors, omissions, or damages caused
by the use of these programs or from the use of the
information contained herein.