Download Document

Chapter 1
Introduction to Physical Geology
Index

Geology
• Geology – The scientific study of the earth.
• Physical Geology
• Physical Geology – A large division of geology
concerned with earth materials, changes of the
surface and interior of the earth, and the forces
that cause those changes.


The Earth’s Interior
• Crust – The outer layer of rock, forming a thin
skin over the earth’s surface.
• Mantle – A thick shell of rock that separates the
earth’s crust above from the core below.
• Core – The central zone of the earth.


More Layers
• Lithosphere – The rigid outer shell of the earth, 70 to 125
or more kilometers thick.
• Asthenosphere – A region of the earth’s outer shell
beneath the lithosphere. The asthenosphere is
of indeterminate thickness and behaves
plastically.
• Fig 1.8


Why understand geology?
• Helps us:
• Avoid Geologic Hazards
• Supplies Things We Need
• To Protect the Environment
• To Understand Our Surroundings


The Theory of Plate Tectonics
• Plate Tectonics – A theory that the earth’s surface is
divided into a few large, thick plates that are
slowly moving and changing in size.
Geologic activities occur at the plate boundaries
• Tectonic Forces – Forces generated from within the earth
that result in uplift, movement, or deformation
of part of the earth’s crust.
• Fig. 1.10


Plate Boundaries
• Divergent Boundaries
• Transform Boundaries
• Convergent Boundaries


Divergent Boundaries
~ Boundary separating two plates moving away from
each other.
• Most divergent boundaries coincide with the crests
of submarine mountain ranges, called mid-oceanic
ridges.
• Fig. 1.11
Back
Fig. 1.11
• Pg. 17
Back
Transform Boundary
~ Boundary between two plates that are
sliding past each other.
• An example is the San Andreas fault in
California.
Back
Convergent Boundary
• ~Boundary between two plates that are moving
toward each other.
• If one plate is capped by oceanic crust and the other by continental
crust, the less dense, more buoyant continental plate will override
the denser, oceanic plate. The oceanic plate sinks along what is
known as a subduction zone, a zone where an oceanic plate
descends into the mantle beneath an overriding plate.
• Fig. 1.12
Back
Fig. 1.12
• Pg. 18
Back
Vocabulary
• Magma – Molten rock, usually mostly silica. The liquid may contain
dissolved gases as well as some solid minerals.
• Erosion – The physical removal of rock by an agent such as running
water, glacial ice, or wind.
• Equilibrium – Material is in equilibrium if it is adjusted to the physical
and chemical conditions of its environment so that it does
not change or alter with time.
• Sediment – Loose, solid particles that can originate by (1) weathering
and erosion of preexisting rocks, (2) chemical precipitation
from solution, usually in water, and (3) secretion by organisms
• Fig. 1.13


Geologic Time
• (put picture of Table 1.1 on pg. 22)


Put picture of page 19-20

Back to the Beginning
Fig. 1.8
• Fig. 1.8 on pg. 15
Back
Fig. 1.10
• Pg. 16
Back
Fig. 1.13
• Pg. 21
Back