ALL ABOUT GUIDING PRINCIPLES AND HISTORY OF GEOLOGY

2. PLATE TECTONICS
GEOLOGIC RECYCLING
UNIFORMITARIANISM

3. WHAT

4.  It is the unifying theory of geology.
 The theory that describes the LITHOSPHERE
(the outer layer of the earth ) as a collection
of rigid plates that move sideways above a
less rigid layer called ASTHENOSPHERE.
 “Tectonic”, refers to the deformation of
the crust as a consequence of plate
interaction.

5. Plates are made of rigid lithosphere.
PLATES ARE
MADE OF RIGID
LITHOSPHERE.
The lithosphere is
made up of the crust
and the upper part of
the mantle.
Below the lithosphere
(which makes up the
tectonic plates) is the
ASTHENOSPHERE.

7. Geologic
RECYCLING

8. • The principle of recycling materials
or using the materials many times .
2 EXAMPLES OF GEOLOGIC CYCLE :
 The Rock Cycle
 The Water Cycle

9.  Is a sequence of events
involving the
formation, alteration,
destruction, and
reformation of rocks as a
result of natural processes
weathering
Sedimentary
weathering
Sedimentary Metamorphic

10.  The eminent 18th
century lawyer,
doctor, gentleman
farmer and founder
of modern
geoscience,
James Hutton,
developed the
concept of the Rock
Cycle to show how
rocks and natural,
physical processes
are interrelated.
 Hutton knew about solar
energy and gravity at the
surface.
But he did not know about
radioactive heating
from inside the earth.
 Solar energy, gravity and
radioactive heating are
the major forces driving
the Rock Cycle.
As a result, the Rock Cycle
will be self-sustaining for
thousands of millions of
years.

11.  The mantle, crust and surface of the earth
can be thought of as a giant recycling machine;
rocks are neither created nor destroyed,
but redistributed and transformed from
one rock type to another.

12. TYPES
OF ROCKS

13. THE ROCK CYCLE

15. Also known as HYDROLOGIC CYCLE
the natural sequence through which water passes
into the atmosphere as water vapour, Precipitates
to earth in liquid or solid form , and ultimately
returns to the atmosphere through evaporation

16.  The process of evaporation from plants is called
TRANSPIRATION. (In other words, it’s like
plants sweating.)
 When rain falls on the land, some of the water is
absorbed into the ground forming pockets of water
called groundwater. Most groundwater eventually
returns to the ocean. Other precipitation runs
directly into streams or rivers. Water that collects in
rivers, streams, and oceans is called RUNOFF.
 When the water in the clouds gets too
heavy, the water falls back to the earth.
This is called PRECIPITATION.
 As water (in the form of gas) rises higher in the
atmosphere, it starts to cool and become a liquid again.
This process is called CONDENSATION. When a large
amount of water vapor condenses, it results in the
formation of clouds.
 During part of the water cycle, the sun heats
up liquid water and changes it to a gas by the
process of EVAPORATION. Water that
evaporates from Earth’s oceans, lakes, rivers,
and moist soil rises up into the atmosphere.

18. UNIFORMITARIANISM?

19.  A geological doctrine suggesting that Earth's geologic
processes acted in the same manner and with essentially the
same intensity in the past as they do in the present and that
such uniformity is sufficient to account for all geologic
change.
The principle of uniformitarianism depends on the
“UNIFORMITY OF LAWS” w/c assumes that the laws of
physics and chemistry have remained constant

20.  James Hutton, Scottish geologist,
chemist, naturalist, and originator
of one of the fundamental
principles of geology—
uniformitarianism, which explains
the features of the Earth's crust by
means of natural processes over
geologic time. And later
popularised by Charles Lyell's
Principles of Geology in 1830.
 Founder of Modern Geology

22.  Geology originated as a modern scientific discipline
 People made stone tools and pottery and had to know
w/c materials were useful for these tasks.
 Ancient Greek and Roman philosophers began the
task of keeping written records relating to geology.
 People began to study mineralogy and made detailed
geologic observations

23.  Brought widespread study of geology including the
publications of Charles Lyell’s book
and the (expeditions that focused on
the collection of geologic and other scientific data).
 the field of geology expanded and geologists
developed the theories of :
 CONTINENTAL DRIFT
 PLATE TECTONICS
 SEAFLOOR SPREADING

24. THEORY

25.  Alfred Wegener
was a German
scientist from 1910
that was very
curious about the
relationship of the
continents.

27. 1. SHAPE OF THE CONTINENTS
2. FOSSIL EVIDENCE
3. ROCK EVIDENCE
4. GLACIAL SCARS

28.  Continents fit together like puzzle pieces

29.  SAME FOSSILS: DIFFERENT CONTINENTS

30.  SAME ROCK:
DIFFERENT RANGE
Existing mountain ranges
separated by vast oceans
contain rocks of identical
mineral content.
 A prime example are the
Appalachian Mountains in
the eastern U.S and the
Caledonian Mountains in
the British Isles.

31. SAME SCARS:
DIFFERENT CONTINENTS

34.  Theory of Plate Tectonics is the idea that the
Earth’s crust and upper mantle are broken into
sections called plates that move around on the
mantle.
LITHOSPHERE
– the crust and part of the upper mantle
ASTHENOSPHERE
– the plastic-like layer below the lithosphere

35. TYPES OF PLATES
CONTINENTAL
• Thicker than oceanic
• Made ofigneous and metamorphic rock
covered by sedimentary rock.
OCEANIC
• Thinner than continental
• Made ofdense igneous rock coveredby
a thin layer ofsediment.

37.  Divergent Boundaries are the boundaries
between two plates that are diverging, or moving
away from each other.

38.  Are the boundaries between two plates that are
converging, or moving towards each other.

39. There are three types of
convergent boundaries:
1. An ocean floor plate
collides with a less dense
continental plate.
2. An ocean floor plate
collides with another
ocean floor plate.
3. A continental plate
collides with another
continental plate.

40. • also known as a transform fault system,
forms as plates slide past one another in
opposite directions without converging or
diverging.

41. LANDFORMS CAUSED BY PLATE TECTONICS:
 A. Rift Valleys (Divergent Boundaries)
 B. Mountain Ranges (Continental-continental
Convergent Boundaries)
 C. Volcanoes (Oceanic-continental Convergent
Boundaries)
 D. Faults (Transform Boundaries)

42. CONVECTION CELLS in the mantle move the plates.
Hot in the center, less dense magma rises up due
to heat.
When the magma reaches the surface, it cools
and sinks back down creating a circular pattern of
movement.
This process happens continually.

44. SEAFLOOR SPREADING
THEOR
Y

45. HARRY HESS
•An American scientist named Harry
Hess proposed the seafloor spreading
theory in 1962.
•The Sea floor spreading theory states
that new ocean crust is being created
at mid-ocean ridges (which are large
mountain chains underwater) and
destroyed at deep-sea trenches.
•This is proof that the plates are
moving along on a “conveyor belt” so
Wegner’s idea on continent drift was
correct.

46.  The force responsible for driving or moving the
plates is convection current.
Convection Currents occur within the mantle of the
earth when hot magma rises and cool magma sinks