Sign up now
to enroll in courses, follow best educators, interact with the community and track your progress.
Download
Continental Drift and Sea Floor Spreading (in Hindi)
2,718 plays

More
Basic concepts of Geography like - Geomorphology explained like continental drift and sea floor spreading.

Danish Khatana
Masters in Biotechnology IIT JAM 2011 (AIR - 479) CSIR NET Life Sciences 2012, DBT JRF 2015, UGC NET Socio - 2018

U
Unacademy user
mam apne science and technology wala ada karbayiya hai,kyun mam.
thanks sir bhot acche se samjh aaya but one more thing aap ki urdu bhi bhot acchi h bolne se pta chla .may allah bless you
Danish Khatana
a year ago
SHUKRIYA Jenaab
Sir aap English medium se hai??? ya Hindi ?? aap essay k liye 1 course bana dijiye please jisme Aapke best model essay bhi shamil ho
Danish Khatana
a year ago
Mai essay banaa chuka hu, Hindi English dono mei
your vedios are very helpful... please keep uploading... thank you very much sir.????
St
Very valueable and easy to understand... Thanks a lot...
and if u please explain more about tactonic plates..
  1. unacadem Geomorphology Basic Theorie.s Geomorphology is a systematic and organized description and analysis of the surface landforms, processes and landscape evolution of the Earth.


  2. unacadem The basic concepts Continental Drift Sea floor spreading . Plate Tectonics . Isostasy


  3. unacademy Continental Drift Father of the concept - (Alfred Wegner) explain the present arrangement of aurasia continents and ocean basins .Wegner hypothesized that super continent (Pangaea) surrounded by a 225 million years ago 150 million years ago huge sea Panthalassa, broke up to form: . (i) Laurasia (N. America, Greenland and all Noth Aneici Asia Asa Eurasia north of the Indian Subcontinent) and Aftica Amenca Australi . (ii) the Gondwanaland (South America, adia Africa, Madagascar, India, South West Asia, Australia and Antarctica). Astirt Earth today na 00 million years ago


  4. unacadem FURTHER . He opined that continents are made of SiAl and Ocean basins of SiMa. According to Wegener continents drifted in two directions: a) Towards the Equator (due to : gravitational attraction exerted by the earth's equatorial bulge). As a result of this drift, the Himalayas and Alps etc, came into existence. The Peninsular Indian and Africa were separated from the Antarctica and Australia. b) The Second drift was towards the west (due to tidal force of the Moon and the Sun). North and South America got separated from Europe and Africa and the Andes and Rockies Mountains came into existence.


  5. unacademy Evidence in support of Continental Drift Similarities are found in the opposing coasts of the Atlantic Ocean. Jig saw of the opposing coasts of Atlantic Ocean. Fossils of glossopteris (a fern - like plant) have been found in rocks of the same age from S. America, S. Africa, India and Australia. Folded mountain ranges at Cape of Good Hope and rocks of Buenos Aires (Argentina) resemble. a) b) c) d) Major lava plateaus of South America, W. Africa, Madagascar, India and Antarctica have the same geological structures.


  6. unacademy Criticism . Wegener was criticized for failing to explain the forces that would permit continents to plough through the ocean of rocks. . He was declared as a crank who carefully selected only those data which supported his hypothesis, ignoring contrary evidences. Wegener died on an expedition in Greenland in 1930. His theory was already eclipsed.


  7. unacademy Sea-floor Spreading . The hypothesis of 'Sea-Floor Spreading' which proves the theory of Continental drift was put forward by Harry H.Hess & Robert Deitz According to Hess, the submarine mountain ranges (Mid-Ocean Ridges) were direct results of upwelling flows of magma from the Asthenosphere. . When magma rises from below, the earth's crust is fractured. The magma spills out and cools to form new sea floor, building the ridges and spreading laterally.


  8. unacademy Sea-floor Spreading . The hypothesis of 'Sea-Floor Spreading' which proves the theory of Continental drift was put forward by Harry H.Hess & Robert Deitz According to Hess, the submarine mountain ranges (Mid-Ocean Ridges) were direct results of upwelling flows of magma from the Asthenosphere. . When magma rises from below, the earth's crust is fractured. The magma spills out and cools to form new sea floor, building the ridges and spreading laterally.


  9. unacademy Sea-floor Spreading Mid-Ocean Ridge Deep-Ocean Trench Volcanoes Rising Magma Rising Magma Sea-Floor Spreading Rising Magma Subduction Zone Mantle 0.0 1.0 2.0 3.0 4.0 5.0 Millions of Years Ago


  10. unacademy FINDINGS . The following three important facts were established by Hess: . The crust below the ocean floor was found to be only 6 to 7 km thick, whereas below the continental surface it was 30 to 40 km Mid-Oceanic Ridges were present in all the oceans. The ocean floors, nowhere, were found to be older than 135 million years, though the oceans are 3.9 billion (3900 million) years old. Ocean floor is constantly regenerated at the mid-ocean ridges and subjected to continents lateral spreading until it is destroyed in the trenches.