Relief orders

Relief orders

1. SEMINAR ON SEMINAR ON
RELIEF ORDERSRELIEF ORDERS



Presented by
PRAMODA G
Geology, 4
th
semester
DoS In Earth Science,
University of Mysore

2. contentscontents
 Introduction
 Classification
First order relief
Second order relief
Third order relief
 Conclusion
 Bibliography

3.  Relief is simply the difference in elevation
between two points.
 The topography of the Earth is a product of
endogenic and exogenic processes.
 When the surface is relatively flat we say it
has low relief.
 Conversely, mountainous regions have high
relief.

4. CLASSIFICATION

The relief features of the earth are
be divided into three orders based
on what created them and their
size.
These are:-

1. FIRST ORDER RELIEF

2. SECOND ORDER RELIEF

3. THIRD ORDER RELIEF

5. First Order Relief
 First order relief features are the tectonic plates/
lithospheric plates or oceanic plates (largest in spatial
extent).
 Two types of plates, continental and oceanic are
differentiated by their rock and mineral composition.
 Continental plates are lighter in density and composed
mostly of granitic rock material rich in silica and
aluminum.
Ex:- Eurasian plate, North American plate, South
American plate, Indo-Australian plate, African plate and
Antarctic plate etc.
 The oceanic plates are made of dense, basaltic rock
composed predominately of silica and magnesium.
Ex:- Pacific plate, Nazca plate, Caribbean plate, Arabian
plate, Philippine sea plate, Cocos plate etc.

6. Major Tectonic Plates Of The World N

7. Second Order Relief

Second order relief features are developed as a result
of plate collision or divergence. When two continental
plates collide it causes the earth to fold and buckle.
 The denser and heavier oceanic plate dives beneath the
lighter less dense continental plate in a process of
subduction.
 Convergence plates collision are comparatively three
types according to oceanic and continental plates, these
are:-
1. Oceanic - Continent
2. Oceanic - Oceanic
3. Continent - Continent

8. OCEANIC – CONTINENT
Ex:- Nazca Plate subduct beneath South American plate that
is forming Andes mountain, Aleutian Trench etc.

9. OCEANIC – OCEANIC

10. CONTINENT - CONTINENT

11. Himalayan mountains ranges formed by continent-continent type of
convergence

12. Plate divergence means two plates moves away from
each
others, created new crust such as Mid- oceanic ridge .
Ex:- Mid Atlantic ridge, Pacific-Antarctic ridge etc.
Rift form where plates diverge from one another. If parallel rifting occurs , Rift
valley will be formed.
Rifting can be accompanied by volcanic activity as magma pours out of the rift.
Ex:- Great rift valley of Africa, Red sea rift.

13. Third Order Relief
 These Features are for the most part created by
erosion and deposition of the surface as opposed to the
movement of tectonic plates.
 Individual landforms are considered in third order and
also no upper limit or lower limit.
 A geomorphic agent/agency in any natural medium
which is capable of securing and transporting earth
materials.
 Mainly, in these order the geomorphic processes are
effect a modification of the earth’s surface forms.

14. Exogenic Endogenic
Processes Processes
Extraterristrial
Processes
Gradation Diastrophism Volcanism

Degradation Fall of
Aggradation Meteorites
Weathering Mass wasting
Running water
Physical Ground water
Chemical Waves, Tides, Currents
Biological & Tsunami
Wind, Glaciers
Geomorphic Processes

15. Pawnee cirque, the bowl shaped feature of the
below figure was caused by an alpine glacier
eroding into the side of a mountain. The bowl-
shaped depression left behind representes a third
order relief feature of the earth.

16. Conclusion:
 The surface features are not only dependent on the various forces that create them,
but the material composition of the earth as well.
 The mineral content of rock, and the type of rock greatly effect their resistance to
geological agent of erosion and hence the surface features of our planet.
 Subduction zones are noted for their frequent earthquake and volcanic activity.
 Marine fossils are found at high altitudes when they were pushed up as result of
the collision.
 The presence of fossil marine organisms on high mountain peaks was used as
evidence to support the theory of plate tectonics.
 One way to distinguish between second order and third order relief features is
one can see the entire form of third order feature but not a second.

17. Arthur N. Strahler & Alan H. Strahler (1987)– Modern physical
geography(Third Edition), Pub:- John Wiley & Sons. P.P.- 217 & 218
Philip G. Worcester (1948)- A text book of geomorphology (Second
edition), Pub:- D. Van Nostrand company ,Inc. , Newyork . P.P.- 13 -34
Ritter, Michael E.(2009) - The Physical Environment: an Introduction
to Physical Geography.
William D. Thornbury – Principles of Geomorphology (Second
Edition), Pub:- New Age International(P) Limited, New Delhi.
http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/title_pa
ge.html
www.google.co.in/images
http://en.wikipedia.org/wiki/