Earth, Moon and Mars: How They Work

1. Earth, Moon and Mars: How They Work Professor Michael Wysession Department of Earth and Planetary Sciences Washington University, St. Louis, MO Lecture 7: Geologic Consent

2. Civilization Exists Through Geologic Consent

3. COMPLEX PLATE BOUNDARY ZONE IN ASIA Northward motion of India deforms all of the region

4. COMPLEX PLATE BOUNDARY ZONE IN ASIA Northward motion of India deforms all of the region Creates many LARGE EARTHQUAKES Pakistan EQ, 2005 Sichuan EQ, 2008 Sumatra EQ, 2004

7. Mt. St. Helens, Following the 1980 Eruption

8. Mt. Mazama erupted in 4860 BC:  42x larger than Mt. St. Helens Crater Lake, Oregon

10. Giant Volcanic Eruption of Krakatau in 1883.

11. The tsunami from the 1630 BCE eruption of Mt. Thera may have given rise to the legend of Atlantis.

12. But the most significant affects on the history of life and civilization come from changes in climate. • Cycles within cycles. • Many different time scales.

13. What drives the long-term temperature changes?

14. Mountains!!  Erosion (Carbonic Acid)  Deposition of Carbonates in the Oceans  Reduced CO2 in Atmosphere  Global Cooling

15. Allegheny Mtns Ouachita Mtns Himalayan Mtns Appalachian Mtns Taconic Mtns

19. What drives the intermediate-term temperature changes?

20. Fluctuations in Earth’s Orbit (Milankovich Cycles)

21. Ellipticity variations: Due to planetary orbits (gravity)

23. What about some of the narrow, sharp spikes? 72,000 years ago

24. Mt. Pinatubo: So much ash & aerosols into the atmosphere that Earth’s temperature dropped, and sunsets were redder.

25. Toba Volcano – 72,000 years ago  280,000 km3 ejected!  1 gigaton tnt explosion!

26. Based on genetic diversity, it is estimated that all modern humans evolved from only 1000-10,000 individuals following the Toba eruption.

29. # of Sunspots Correlates with Temperature: Many Sunspots = Warm Few Sunspots = Cold

30. Shorter Changes: Events like El Niño

31. By 100,000 years ago, Homo Sapiens was emerging as dominant hominid. Why?

32. ?? Selection for large brains during strong Ice Ages that occurred 120,000-90,000 years ago??

33. 50,000-40,000 years ago there was a cultural explosion in Europe. Why? Warming trend in Europe. Life was easier?

34. North American Mammoths evolved in Asia. How did they get here 20,000 years ago?

35. 20,000 years ago was time of Ice Ages. Sea levels were low. Mammoths walked here! • Native Americans followed 14,000 years ago!!!!

36. The beginnings of civilization didn’t occur until 10,000 years ago. Why?

37. The start of a warm and relatively stable climate period!!!

38. Many cultures have a myth similar to the story of the expulsion from Eden. Why?

41. Rising Sea Levels After the End of the Ice Age forced many people from their homelands!! Ancient Persian Gulf Shoreline

42. The Egyptian and Semitic peoples originated in Eastern Europe. Why did they leave?

43. The Black Sea flooded dramatically 5,600 BCE!! Most of these cultures have similar flood myths!!

44. 3000 BCE: Time of alternating droughts and flooding.  Complex societies like Akkadian Empire evolve in order to survive.

45. Story of Joseph warning the Egyptian Pharaoh to prepare for 7 lean years.

46. 2200 BCE: Period of extended drought causes Akkadian Empire to collapse.

47. 1900 BCE: Cold and dry period.  Desertification destroys Indus Civilizations.

48. 1630 BCE: eruption of Mt. Thera * Minoan Culture ends 200 years later, overrun by Myceneans

49. 1200 BCE: Variable atmospheric circulation patterns hurt agriculture.  Mycenean culture collapses.

50. 1200 BCE: Variable atmospheric circulation patterns hurt agriculture.  Also causes mass migrations of Phrygian and Hittite peoples.