In this ppt there is detail discussion of GEOLOGICAL TIME SCALE TEORIES OF ORIGIN OF EARTH AND CONTINENTAL DRIFT HEROY BY - TAYLOR

1. GEOGRAPHY
UNIT 1 – GEOMORPHOLOGY
LECTURE – 1
TOPICS
• GEOLOGICAL TIME SCALE
• THEORIES OF ORIGIN OF EARTH
• CONTINENTAL DRIFT THEORY by -TAYLOR

2. UNIT-I
Geomorphology
Continental Drift, Plate Tectonics, Endogenetic and Exogenetic forces. Denudation and Weathering, Geomorphic
Cycle (Davis and Penck), Theories and Process of Slope Development, Earth Movements (seismicity, folding,
faulting and vulcanicity), Landform Occurrence and Causes of Geomorphic Hazards (earthquakes, volcanoes,
landslides and avalanches).

6. Theories of origin of the
earth
पृथ्वी की उत्पत्ति क
े बारे में वैज्ञानिक अवधारणाओं |
अद्वैतवादी संकल्पिा (Monistic Concept):
क ांट की व यव्य र शि पररकल्पन (Kant’s Gaseous Hypothesis)
ल प्ल स की ननह ररक पररकल्पन (Nebular Hypothesis of Laplace)
द्वैतवादी संकल्पिा (Dualistic Concept):
1. चैम्बरशलन व मोल्टन की ग्रह णु पररकल्पन (Planetsimal Hypothesis):
2. जेम्स जीन्स (1919 ई.) व जेफररज (1921 ई.) की ज्व रीय पररकल्पन (Tidal Hypothesis):
3. रसेल की द्वैत रक पररकल्पन (Binary Star Hypothesis):
4. ऑटो श्ममड की अांतरत रक धूल पररकल्पन (Inter-Steller Dust Theory):
5. फ्र
े ड होयल व शलटटलटन की अशिनव त र पररकल्पन :

7. Total of 8 theories of the origin of the universe.
1.Gaseous hypothesis of Kant
2.Nebular hypothesis of Laplace
3.Planetesimal hypothesis of Chamberlin
4.Jean and Jeffery’s tidal theory
5.Russel’s binary Star Hypothesis
6.Hoyle’s supernova hypothesis
7.Schmidt’s interstellar hypothesis
8.Big bang theory

8. 1. GASEOUS HYPOTHESIS OF KANT
Immanuel Kant, the Prussian philosopher, presented his gaseous hypothesis in his treatise entitled “The
General Natural History and Theory of the Heavens or the Essay on the Working and Mechanical
Origin of the Entire Universe on the Basis of Newtonian Laws" in 1755.
Obviously, Kant’s hypothesis was primarily based on Newton’s laws of gravitation and rotatory motion.
He assumed that primordial matter (conceived as supernaturally created) was scattered in the universe.
This matter consisted of small, hard and cold particles. These particles were attracted towards one
another under the influence of gravitational pull.
In due course of time they began to collide against one another. The friction between these particles
generated heat and the temperature of the primordial matter started rising. The collision also generated
random motion in the primordial matter and angular velocity was produced.
Thus, the original cold and motionless cloud of primordial matter became a vast hot nebula. It was so
vast that it extended from the sun in the centre to as far away as the orbit of the outer-most planet. The
rise in temperature changed the state of primordial matter from solid to gaseous.

9. The repeated collision of the particles increased random motion and angular velocity to such an extent
that the nebula started rotating at a terrific speed and large amount of centrifugal force1 2 was generated.
When centrifugal force became larger than the gravitation force (force towards the centre), a ring was
thrown away from the equator of the nebula. This process was repeated nine times and nine rings were
formed. The irregularity of the rings caused the development of cores (knots) which led to the formation of
corresponding planets.
Our earth is a planet formed from one of the nine rings which got separated from the nebula. By small
scale repetition of the same process, the gaseous mass of some of the planets throw away rings which
became their satellites.
The remaining part of the original gaseous mass is our present sun. Thus the entire solar system
comprising the sun, nine planets and their satellites came into being.
Kant was so confident about his hypothesis that he proclaimed, “Give me matter, and I will show you
how to make a world of it.”

10. i. कांट की वायव्य राशि पररकल्पिा (Kant’s Gaseous Hypothesis):
जममन द िमननक क ांट ने 1755 ई. में न्यूटन क
े गुरुत्व कर्मण क
े ननयमों पर आध ररत व यव्य र शि
पररकल्पन क प्रनतप दन ककय । इसक
े अनुस र एक तप्त एवां गनतिील ननह ररक (Nebula) से कई
गोल छल्ले अलग हुए, श्जनक
े िीतलन से सौरमांडल क
े ववशिन्न ग्रहों क ननम मण हुआ ।
पृथ्वी िी इन्हीां में से एक है । परांतु, इस शसद्ध ांत में क ांट ने गणणत क
े गलत ननयमों क अनुप्रयोग
ककय , क्योंकक यह कोणीय सांवेग क
े सांरक्षण क
े ननयम क अनुप लन नहीां करत है ।

13. Merits of Kant's Theory
1.First theory based on gravity and motion. Kant’s theory was the first theory which is based on
fundamental scientific facts such as Newton’s laws of gravity and motion.
2.Simple. Kant’s hypothesis appears to be simple and sounds more logical.
3.Trend setter. This theory provided ground for developing future ideas about the origin of the earth.
For example the Nebular theory of Laplace was immensely influenced by his theory and it paved way
for postulation of Laplace’s theory.

14. Demerits of Kant's Theory
Although this theory was held in high esteem for about half a century, it has been criticised on the
following ground :
1.Origin of primordial matter not explained. The basic assumption on which Kant based his
hypothesis was that there was primordial matter in the universe. He has not explained the source of
origin of the primordial matter.
2.Problem of Gravitational Pull. According to Kant’s view, the collision between the particles of the
primordial matter was due to gravitational pull. Scientists have asked whether this force did not exist
before the collision, and if it existed, what prevented it to act and collision to take place.
3.Generation of angular momentum not explained. Kant did not explain how angular momentum was
generated in the primordial matter after collision of its particles. According to Newton’s first law of motion
‘a body remains at rest or in uniform motion unless and until an external force is applied on it.’ Thus, it is
clear that some external force is required to generate angular momentum. Kant did not mention any
such force and could not explain it satisfactorily.
4.Against the Law of Conservation of Angular Momentum. Kant assumed that rotation was set up,
i.e., angular momentum was produced in the nebula by the collision of its particles. This is against the
well known law of conservation of angularmomentum. In the words of Otto Schmidt, ‘‘According to law of
conservation of angular momentum, the sum total of rotation in a closed system remains constant. The
rotation may be transferred from one body to another, but the sum neither increases nor decreases.”

15. 2. Nebular hypothesis of Laplace
Laplace (French Mathematician) propounded his theory in 1796. Laplace’s
nebular hypothesis was in some way similar to the Gaseous hypothesis of Kant
and appears like the modified version of Kant’s hypothesis.
Book entitled ‘Exposition of the World System’.
Nebula – It is a primordial (primitive) amorphous (without shape) mass of
cloud of gas and dust.
Assumptions
•He assumed that there was a huge and hot gaseous nebula in the space.
•From the very beginning huge and hot nebula was rotating on its axis.
•The nebula was continuously cooling due to loss of heat from its outer
surface through the process of radiation and thus it was continuously reduced
in size due to contraction on cooling.

16. ii. लाप्लास की निहाररका पररकल्पिा (Nebular Hypothesis of Laplace):
फ्र ांसीसी ववद्व न ल प्ल स ने 1796 ई. में क ांट क
े शसद्ध ांत को सांिोधधत करते हुए बत य कक एक ववि ल तप्त
ननह ररक से पहले एक ही छल्ल ब हर ननकल जो कई छल्लों में ववि श्जत हो गय तथ ये छल्ले अपने वपतृ
छल्ले क
े च रों ओर एक टदि में घूमने लगे ।
ब द में इन्हीां क
े िीतलन से ववशिन्न ग्रहों क ननम मण हुआ, श्जनमें पृथ्वी िी ि शमल है । इस पररकल्पन क
े
अनुस र सिी ग्रहों क
े उपग्रहों को अपने वपतृ ग्रह की टदि में घूमन च टहए । परन्तु, इस तथ्य क
े ववपरीत
िनन तथ बृहस्पनत क
े उपग्रह अपने वपतृ ग्रह क
े ववपरीत टदि में भ्रमण करते हैं

17. According to Laplace
•Since, Nebula was continuously reduced in size due to gradual loss of heat
from the outer surface of the nebula through radiation.
•Thus, Reduction in the size and volume of the nebula increased the circular
velocity (rotatory motion) of the nebula.
•Due to the increase in velocity, nebula started spinning at very fast speed
and consequently the centrifugal force becomes so great that it exceeded the
centripetal force.
•Consequently, the Outer surface was condensed due to excessive cooling and
so it could not rotate with the still cooling and contracting the
central nucleus of the nebula.
•And, Thus the outer ring was separated from the remaining part of the
nebula.
•And this separated ring started moving around the nebula.
•Laplace further maintained that the original ring was divided into nine
rings and each ring moved away from the outer ring.
•Thus, nine planets were formed from the nine rings and the remaining central
nucleus of the nebula become the Sun.

19. Evaluations
•He did not describe the source of the origin of the nebula.
•He did not explain that, why did only 9 rings come out from irregular
ring detached from the nebula?
•If the sun is the remaining nucleus of the nebula as claimed Laplace, it
should have a small bulge around its middle part which would point out the
probable separation of the irregular ring from the sun but there is no
such bulge in the middle part of the sun.
•According to the nebular hypothesis all satellites should revolve in the
direction of father planets but few satellites of Saturn and Jupiter
revolve in the opposite direction of their father planets.
•The nebular hypothesis is unable to explain the peculiar distribution of
present-day angular momentum in our solar system.
Outcome: The merit of the theory lies in the fact that it is the most
acceptable explanation in explaining the layered structure of the earth’s
interior.

20. 3. The planetesimal hypothesis of Chamberlin (1905)
The planetesimal hypothesis of Chamberlin belongs to the dualistic concepts
of the origin of the Earth.
According to Chamberlin initially there were two heavenly bodies (stars) in
the universe –
1.Proto-Sun
2.and its Companion Star or Intruding star
The behavior and properties of proto-sun were not like other stars, It was
formed of very small particles which were cold and solid.
Theory: When the intruding star came very close to the the Proto-Sun
infinite number of small particles were detached from the outer surface of
proto-sun due to massive gravitational pull exerted by the giant intruding
star. This matter which is dust, gases, rock fragments eventually accrete
forming planets & other celestial bodies that revolve around the proto sun.

21. Planetesimal hypothesis not only explains the origin of the earth but
also throws light on the structure of the earth, the origin of its
atmosphere and continents and ocean basins.

22. 4. Jean and Jeffery’s tidal theory
This theory is somewhat similar to Chamberlin’s theory that an intruding
star ejects matter from the proto sun. Chamberlin, in his theory, had
assumed the proto sun to be initially as a cold body whereas the Tidal
theory assumes the proto sun to be hot and incandescent.
According to Tidal theory, the matter ejected are not randomly thrown dust,
gases, planetesimal.
The ejected matter was in the shape of a cigar and was called Filament from
which the planets & other celestial bodies accrete.
This theory is the best interpretation in explaining the sizes of the
planets as they have arranged themselves away from the sun.

23. 5. Russel’s binary Star Hypothesis
There is a binary star system (two stars coupled together and rotating
around a fixed center of mass).
The intruding star comes close to the binary stars & eject matter from one
of the stars. (It doesn’t explain what happened to the intruding star and
the remainant of the star from which matter got ejected.)
The ejected matter circulates into planets and revolves around the proto
sun.
This theory is convenient to explain why the composition of planets is
different from the sun.

25. 6. Hoyle’s supernova hypothesis
According to Hoyle initially there were two stars in the universe –
(1.)Primitive Sun and
(2.) Companion star
The companion star was giant and later on became supernova due to nuclear
reaction.
Over time, all of the hydrogen nuclei of companion star were consumed in the
process of nuclear reaction and it collapsed and violently exploded.
The Violent explosion of companion star resulted in the spread of enormous
mass of dust which started revolving around the primitive sun in the form of
a circular disc
The matter of this disc became building material for the formation of the
future of planets.
Thus, the planets of our solar system were formed due to condensation of the
matter of the disc.

27. 7. Schmidt’s interstellar hypothesis
According to this theory, the initial universe comprised of stars &
randomly distributed matter filling up the space in between.
According to Schimidt, this dark matter, started to revolve around the
primitive rotating sun and gradually the dark matter stars accreting &
condensing & thus forming the solar system.
Though Schimidt did not explain the mode of origin of these dark matters.
These dark matters were called ‘inter-stellar dusts’ by Schimidt.
This theory may be considered as explaining the processes that preceded the
Nebular accretionary process of Laplace & Kant.

29. 8. BIG BANG THEORY
Big Bang theory’s idea was first given by George LeMaitre in the 1920s & was
gradually contributed by many scientists. But an important role was played by
Gamenov (1970’s).
According to this theory, Everything in the universe has emerged from a point
known as the singularity, 15 billion years ago.
The galaxies moved apart from one another as the empty space between them
expanded.
Theory:
The universe expanded from a very high density & high-temperature state.
There was a major cosmic explosion 13-15 bn yrs ago from which all the matter
of the universe was thrown out which eventually accreted to form stars, solar
system and celestial bodies.
Evidence in support:
1. Red Shift: As an object (light) moves away from us, its wavelength increases
& shift to the Red end of the spectrum (Called Red Shift).
2.CBMR: Electromagnetic Radiation which was present shortly after the big bang,
is now observed as background microwave radiation.

31. Continental Drift Theory of Taylor
In this article we will discuss about the continental drift theory of Taylor.
F.B, Taylor postulated his concept of ‘horizontal displacement of the continents’ in the year of
1908 but it could be published only in the year 1910. The main purpose of his hypothesis was to explain
the problems of the origin of the folded mountains of tertiary period.
Infact, F.B. Taylor wanted to solve the peculiar problem of the distributional pattern of tertiary folded
mountains.

33. The north-south arrangement of the Rockies and the Andes of the western margins of the North and
South Americas and west – east extent of the Apline mountains (Alps, Caucasus, Himalayas etc.) posed a
serious problem before Taylor which needed careful explanation. He could not find any help from the
‘contraction theory’ to explain the peculiar distribution of tertiary folded mountains and hence he
propounded his ‘drift or displacement theory’.
Taylor started from cretaceous period. According to him there were two land masses during creta-
ceous period. Lauratia and Gondwanaland were located near the north and south poles respectively.
He further assumed that the continents were made of sial which was practically absent in the oceanic
crust. According to Taylor continents moved towards the equator. The main driving force of the
continental drift was tidal force.
According to Taylor, continents were displaced in two ways e.g.:
(i) Equator ward movement, and
(ii) Westward movement but the driving force responsible for both types of movement was tidal force
of the moon.

35. Lauratia started moving away from the North Pole because of enormous tidal force of the moon
towards the equator in a radial manner. This movement of land mass resulted into tensional force near
the North Pole which caused stretching, splitting and rupture in the landmass. Consequently, Baffin
Bay, Labrador Sea and Davis Strait were formed.
Similarly, the displacement of the Gondwanaland from the South Pole towards the equator caused
splitting and disruption and hence the Gondwanaland was split into several parts. Consequently, Great
Australian Bight and Ross Sea were formed around Antarctic Continent.
Arctic sea was formed between Greenland and Siberia due to equator ward movement of Lauratia.
Atlantic and Indian oceans were supposed to have been formed because of filling of gaps between the
drifting continents with water. Taylor assumed that the landmasses began to move in lobe form while
drifting through the zones of lesser resistance. Thus, mountains and island arcs were formed in the
frontal part of the moving lobes.
The Himalayas, Caucasus and Alps are considered to have been formed during equator ward
movement of the Lauratia and Gondwanaland from the north and south poles respectively while the
Rockies and Andes were formed due to westward movement of the land- masses.

36. Evaluation:
Since F.B. Taylor’s main aim was to explain the origin of the tertiary folded mountains and hence he made
the continents to move at a very large scale.
In fact, some sort of horizontal movement of the land masses was essential for the origin of mountains but
the displacement of land masses up to 32-64 km would have been sufficient enough for the purpose.
Contrary to this Taylor has described the displacement of the landmasses for thousands of kilometres.
Secondly, the mode of drift as suggested by Taylor has also been erroneous.
If the tidal force of the moon was so enormous during cretaceous period that it could displace the
landmasses for thousands of kilometers apart then it might have also put a break on the rotatory motion of
the earth and thus the rotation of the earth might have stopped within a year.
According to A. Holmes neither tidal force nor any external force can drift the continents apart and can
help in the formation of mountains. The responsible force must come from within the earth.

37. Though the concept of F.B. Taylor is not acceptable but his hypothesis is considered to be
significant on the ground that Taylor raised his voice very forcefully through deductive
postulation against the prevalent concept of the permanency of the continents and ocean basins
and forcefully objected to the ‘contraction theory’ and showed a new direction to solve the prob-
lem of the origin of the continents and ocean basins. A. Holmes has rightly remarked, ‘but Taylor
must be given credit for making an independent and slightly an earlier start in this precarious
field.’