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Age of The Earth - 1 (in Hindi)
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Age of the earth- part 1

Ashish Malik is teaching live on Unacademy Plus

Ashish Malik
Verified UPSC Educator@Unacademy Plus, Writer, Poet, Alignment Design engineer, Motivational speaker, YouTuber, Blogger, Counsellor

U
Unacademy user
thanks very much sir ji
Ashish Malik
2 years ago
thank you so much
Would you also cover Indian and world geography?
Ashish Malik
2 years ago
Yes. I will try to cover all the topics from india and world geo
  1. AGE OF THE EARTH GEOGRAPHY BY ASHISH MALIK


  2. ABOUT ME: . Ashish Malik (B.E. Civil) Appeared for UPSC CSE . Mains twice (2016,2017) . Freelancer and Faculty of GS . Follow me on UNACADEMY at: https:/lunacademy.com/user /AshishMalik-8996


  3. AGE OF THE EARTH 4.5 billion years old Age of earth - Geological time scale Calculated using Radio Isotope Dating of rocks


  4. GEOLOGICAL TIME SCALE Two types - 1. Relative Time Scale 2. Absolute Time Scale


  5. RELATIVE TIME SCALE Classical period of Geomorphological Studies . Relative age of formation of structure that forms the landforms . Mainly contributed by Sir Charles Lyell . 4 principles of Stratigraphy . Principle of superimposition (low lying stratas are always older) Principle of faunal succession (low lying stratas will incorporate fossils of less developed organisms) than the rock stratas they intrude in. are always subjected to erosion, transportation and deposition. . Principle of cross bedding-magma intrusions are always younger . Principle of fragmental inclusion- rock fragments of older rocks


  6. ISSUES WITH RELATIVE TIME SCALE Projected a limited practical value as it did not take into account the concept of "Unconformities" 19


  7. UNCONFORMITIES? Part of the time not represented by any type of rock formation. Gaps or Break in the record Three types- 1. Angular unconformity 2. Disconfirmity . 3. Non-conformity


  8. Angtar unccrionnit


  9. ABSOLUTE TIME SCALE Age of the earth is divided into Eras, Period, Epoch and Age. Their chrono stratigraphic units(time rock units) Eras- Erathem Period- System Epoch- Series Age- Stage


  10. PRE-CAMBRIAN ERA (4.5 BILLION YEARS- 570 MILLION YEARS) . Hadean Era- oldest era (4.5 by-3.8 by) - formation of continents and oceans Archean Era(Azoic Era) (3.8by-2.5by)- formation of ancient mountains, plateaus, shield of the world- economic significance- Metalliferous mineral resources (Kargoorlie range- Aus-Gold, Manchuria-China-Iron ore) . Proterozoic era- (2.5by-570 my)- witnessed Universal unconformity (Ep-Archean Unconformity)- no rock formation.


  11. MESOZOIC ERA (245MY-65MY) Development of diversified life- Aquatic, terrestrial and Ariol . Periods- 1. Triassic (245-208my) - Frogs and Turtles 2. Jurassic (208-144my) -Age of Dinosaurs, Breaking of Continents 3. Cretaceous (144-65my)- Extinction of Dinosaurs


  12. TERTIARY (65-2MY) Tertiary (65-2my) - Young relief, Maximum Volcanic activity, Lignite coal formation. Epoch 1. Paleocene (65-57my) small mammals 2. Eocene (57-37my) rabbits and hare 3. Oligocene (37-24my) Ist Ape 4. Miocene (24-5my) Flowering plants and trees 5. Pliocene (5-2my) Homonid ape, Modern Horse