Transcript File - WatchYourSteps

The Land Builds Up
Atoc
Bonggot
Lara
Sanguenza
Valiente
The Land Builds Up
 Mountain Formation
 Continental Drift Theory
 Sea-floor Spreading
 Plate Tectonics (Plate Tectonics and the
Philippines)

Mountains in the Philippines
Mountain Formation
What is a Mountain?
• A mountain is a landform
that rises high above the
surrounding terrain in a
limited area.
What do Mountains
look like?
• Mountains usually have
steep, sloping sides and
sharp or slightly rounded
ridges and peaks.
• Mountains can be rocky
and barren.
What do Mountains
look like?
How are mountains
formed?
• Mountains are formed by
• Mountains usually have
slow but gigantic
steep, sloping sides and
movements of the earth's
sharp or slightly rounded
crust
ridges and peaks.
• Mountains can be rocky
and barren.
What different types of Mountains are there?
1. Fold mountains
Himalayan Mountains in Asia
the Andes in South America
the Rockies in North America
2. FAULT-BLOCK MOUNTAIN
the Sierra Nevada mountains in North America
3. Dome Mountains
4. Volcanic Mountains
Mt. Pinatubo in the Philippines
Continental Drift
Theory
Continental Drift Theory
the movement of the Earth's continents
relative to each other by appearing to drift
across the ocean bed
Sir Francis Bacon
Made first map of the
Atlantic Ocean (1620)
Noticed parallelism of
opposite shores
Alfred Wegener
A german geologist and
meteorologist who first
proposed the continental
drift
The Origin of Oceans and Continents
He hypothesized that there was a gigantic
supercontinent 200 million years ago, which he named
Pangaea, meaning "All-earth"
Pangaea started to break up into two smaller
supercontinents, called Laurasia and Gondwanaland
Terms to remember:
Panthalassa - large ocean surrounding
supercontinent
Laurasia - Europe and North America joined
together
Gondwanaland - Southern hemisphere portion of
supercontinent
Wegener's Evidences
*Rock Types and Structures*
Match - Africa and South America
Wegener matched at shorelines, later Bullard gets
better match at edge of continental shelf
*Paleoclimatic evidence*
Gondwanaland glaciations
Sea-floor Spreading
Sea-floor
Spreading
The process in
which the ocean
floor is extended
when two plates
move apart
As Magma rises through the cracks and seeps
out onto the ocean floor, the plates move apart
thus spreading the sea-floor
• When magma piles up along the crack, a long chain
of mountains forms gradually on the ocean floor
Ie. mid-Atlantic
ridge; pillow
basalt
Mid-ocean Ridge - a place where two of the Earth's
tectonic plates are slowly moving apart from each other
The mid-ocean ridge system circles the entire Earth, somewhat like
the seams of a baseball
 The boundaries where the plates move
apart are constructive
 new crust is being formed and added to the ocean
floor
 The ocean floor gradually extends and thus
the size of these plates increases
Subduction – the process in which
smaller plates melts back to the earth
Subduction
Deep ocean Trenches
Trenches deep under water that form where the oceanic crust
bends downwards
Marianas Trench
Major characteristics of the seafloor:
• the age of the seafloor is progressively older away from
mid-ocean ridges;
• older parts of the seafloor have the greatest potential to
have accumulated sediments over the longest time
Evidences of sea-floor spreading
 Presence of pillow shaped rocks
Drilling into
the sea floor
 The closer you get to the mid-ocean ridge, the younger
the rocks. The farther you get, the older the rocks.
Plate Tectonics
Plate Tectonics
is a scientific theory that describes the largescale motions of Earth's lithosphere
Main features:
• The Earth's surface is made up of a series of large plates;
• These plates are in constant motion travelling at a few
centimetres per year;
• The ocean floors are continually moving, spreading from
the centre and sinking at the edges;
• Convection currents beneath the plates move the plates in
different directions;
• The source of heat driving the convection currents is
radioactive decay;
The movement of the plates creates three types of
tectonic boundaries:
 Convergent - where plates move into one another;
 Divergent - where plates move apart;
 Transform - where plates move sideways in relation to each
other
Convergent Boundaries
plates serving landmasses collide, the crust crumples and
buckles into mountain ranges
convergent boundaries also occur where a plate of ocean dives,
in a process called subduction
Divergent Boundaries
magma from deep in the Earth's mantle rises toward the
surface and pushes apart two or more plates. Mountains
and volcanoes rise along the seam.
Transform Boundaries
two plates grind past each other along what are called strike-slip faults.
These boundaries don't produce spectacular features like mountains or
oceans, but the halting motion often triggers large earthquakes
Age of the Sea Floor
*This figure displays the estimated age of sea floor crustal plates with red
the youngest and blue the oldest
Mountains in the
Philippines
Mt. Apo
location : island of Mindanao
Mt. Pulag
location : Luzon
Mt. Kitanglad
location: Bukidnon
Mount Mayon
location: Albay
Mt. Dulang
location: Lantapan, Bukidnon
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