Geology of Earth

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Geology of Earth

  1. 1. Presented by Mohit kumar Pankaj Arun kumarAnkit srivastava 1
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  4. 4. BIG BANG THEORY4
  5. 5. BIG BANG EXPANSIONAPPROXIMATELY 13.7 BILLION YEARS AGO The whole universe was compressed into the confines of anatomic nucleus. Known as a singularity, this is the momentbefore creation when space and time did not exist. According to the prevailing cosmological models thatexplain our universe, an ineffable explosion, trillions ofdegrees in temperature on any measurement scale, that wasinfinitely dense, created not only fundamental subatomicParticles and thus matter and energy but space and timeitself. These events was occurred are termed as Big bang. 5
  6. 6. ORIGIN OF GALAXIESGravity makes hydrogenand helium gas coalesceto form giant clouds that willbecame galaxies, smallerclumps of gas collapse toform the first stars. 6
  7. 7. ORIGIN OF SOLAR SYSTEMThere are three theories regarding the originof the solar system:- Nebula hypothesisCollision or encounterhyothesisPlanetesimal hypothesis 7
  8. 8. NEBULA HYPOTHESIS` Planets and their satellites were formed at same time as the sun. Space was filled by a rotating cloud (nebula) of hot gas and dust, as it cooled began to contractNote: It is most acceptable theory, as its modification has been made. 8
  9. 9. Drawbacks of nebula hypothesis• The mass of material in each ring would be too small to provide the gravitational attraction needed to cause the ring to condense into a planet.• As the nebula contracted, the largest part of the angular momentum would remain associated with the main mass that condensed to form the Sun, which disagrees with the observed distribution of angular momentum in the solar system. 9
  10. 10. COLLISION OR ENCOUNTER HYPOTHESISIt assumed that the Sun was formed before the planets.The gravitational attraction of a closely passing star or the blast of a nearby supernova explosion drew out a filament of solar material that condensed to form the planets. 10
  11. 11. Drawbacks of collision hypothesisThe solar material would have been so hotthat it would dissipate explosively into spacerather than condense slowly to form theplanets. 11
  12. 12. PLANETESIMAL HYPOTHESIS The discredited theory that the close passage of a star to the sun caused many small bodies (planetesimals) to be drawn from the sun, eventually coalescing to form the planets. The planets and satellites of the solar system were formed by gravitational aggregati- on of planetesimals. 12
  13. 13. ORIGIN OF THE EARTHThere are several formation process tookplace resulting in the origin of the earth:- • Crust, mantle and core formation. • Atmosphere formation • Hydrosphere formation • Lithosphere formation
  14. 14. The Age of the Earth 4.6 billion years old = 4,600,000,000Image courtesy of NASA, http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg#file
  15. 15. EARTH HISTORY GEOLOGICAL TIME SCALE 15
  16. 16. The earth’s 4.6 billionyear history is dividedinto major units of time: Precambrian Time Paleozoic Era Mesozoic Era Cenozoic Era Image created by Jason Brechko for Lake George Association (Lake George, NY) http://www.lakegeorgeassociation.org/geology_facts.htm 16
  17. 17. Precambrian Time• 4.6 billion years before present to 544 million years before present• Longest era with a sparse fossil record• Origin of earth’s crust, first atmosphere, and first seas• Earliest fossils of cyanobacteria use photosynthesis to produce oxygen• Ozone layer in the atmosphere is formed from oxygen Image courtesy of http://www.sharkbay.wa.gov.au/tourism/what_to_see_and_do/images/stromatolites_lge.jpg Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 17
  18. 18. Paleozoic era• 544 million years before present to 245 million years before present• Marine communities flourish• Early fishes develop• Origin of amphibians, insects & reptiles• Recurring ice ages/ Appalachians mountains form• Spore-bearing plants dominate Images courtesy of: http://discover.edventures.com/images/termlib/p/paleozoic/support.gif, http://en.wikipedia.org/wiki/Trilobites Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 18
  19. 19. Paleozoic era (continued)…• 286 - 248 million years before present: c Supercontinent of Pangea forms• 248 million years before present: MASS EXTINCTION- 90 % of all known families lost! Image courtesy of http://www.ig.utexas.edu/research/projects/plates/teaching_ideas.htm?PHPSESSID=def1b9 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 19
  20. 20. Mesozoic Era• 245 million years before present - 65 million years before present• The age of the dinosaurs!• Gymnosperms dominate land plant/ origin of angiosperms - flowering plants• Origin of mammals & birds• 145 million years before present - asteroid impact? MASS EXTINCTION• Pangea begins to separate/ Rocky mountains form Image courtesy of http://nascarulz.tripod.com/dinomain.html Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 20
  21. 21. 65 million yearsbefore present….• ASTEROID IMPACT!• Mass extinction of ALL dinosaurs and many marine organisms• End of the Mesozoic era Image courtesy of NASA: http://www.nasaexplores.com/show2_912a.php?id=01-074&gl=912 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 21
  22. 22. Cenozoic Era• 65 million years before present - today• Present era we live in• Continued evolution and adaptations of flowering plants, insects, birds, mammals• Mammals dominant• Major crustal movements & mountain building (Alps & Himalayan mountains form) Image courtesy of: http://www.karencarr.com/gallery_Cenozoic_arch.html Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 22
  23. 23. And during the• Cenozoic era… The most primitive hominid (human ancestor) evolves - approximately 4.4million years before present• The first modern humans (homo sapiens) evolved approximately 100,000 years before present Image courtesy of: http://www.wilderdom.com/images/evolution/8.jpg
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