1. From Fossils To Space Geology #1

2. What Do We Know?

9. Solar Nebula Theory

10. The Solar System

11. The Primordial Earth

14. The Solar Nebula Theory 5,000 Ma4,600 MaFusion 4,500 MaMars-sized impactor Present

15.  Central disk: Sun (98.8%) Hadean Earth  accretion and differentiation

16. Hadean Earth  Solid inner & liquid outer core generate magnetic field  deflect solar wind Formation of Moon followed differentiation.

17. Hadean Earth  Solid inner & liquid outer core generate magnetic field  deflect solar wind Formation of Moon followed differentiation.

18. Hadean Earth  Composition & Timing

19. Hadean Earth  Meteorites—leftovers Ordinary chondrites 4,600 Ma Carbonaceous chondrites (5% organics) Iron (nickel) meteorites Stony-iron meteorites

20. Earth to Sun  90,000,000 miles (150 mill Km) Earth to Moon  225,000 miles (380,000 Km) Planet density decreases with distance--solar wind

21. Earth’s position in the Solar System: Earth to Sun  90,000,000 miles (150 mill Km) Extremely important: further away  ice closer in  steam

22. Hadean Atmosphere  outgassing CO 2 (carbon dioxide), H 2 O (water vapor), CO (carbon monoxide), H 2 (hydrogen gas), HCl (hydrogen chloride), N 2 (nitrogen gas), CH 4 (methane), NH 3 (ammonia), CH 2 O formaldehyde), HCN (cyanide)

23. Hadean Atmosphere  What’s missing? Oxygen generated by: 1. photochemical dissociation 2. photosynthesis

24. Oxygen Revolution  Archean Evidence: 1. Banded iron formations  ocean sediments start ~3,000 Ma: end ~1,800 Ma –UV radiation, purple bacteria, cyanobacteria

25. Oxygen Revolution  Archean Evidence: 1. Banded iron formations  ocean sediments start ~3,000 Ma: end ~1,800 Ma –UV radiation, purple bacteria, cyanobacteria

26. Oxygen Revolution  Proterozoic Evidence: 1.Banded iron formations  2.Terrestrial red beds  red rocks on land start ~2,300 Ma continues today

27. Oxygen Revolution  Proterozoic Evidence: 1.Banded iron formations  2.Terrestrial red beds  red rocks on land 3.Unstable minerals  Uraninite not present since 2,300 Ma

28. Oxygen Revolution  Proterozoic Evidence: 1.Banded iron formations  2.Terrestrial red beds  red rocks on land 3.Unstable minerals  Uraninite 4.Marine copper deposits  only with oxygen began ~1,700 Ma

29. Oxygen Revolution  Proterozoic Evidence: 1.Banded iron formations  2.Terrestrial red beds  red rocks on land 3.Unstable minerals  Uraninite 4.Marine copper deposits  only with oxygen 5.Presence of limestones  Proterozoic ocean (2,000 Ma) carbon dioxide rich  no carbonates

30. Oxygen Revolution  Phanerozoic Evidence: 1.Banded iron formations  2.Terrestrial red beds  3.Unstable minerals  4.Marine copper deposits  5.Presence of limestones  Free oxygen leads to ozone  UV protection

33. Hadean Hydrosphere Hydrologic cycle: Water sweated from interior & condensed as rain Oceans estimated at 4.2 BYA, Australian zircons

34. Ancient crust 4,000 Ma marks beginning of Archean

35. Anatomy of a Tectonic Plate

37. Formation of Archean Continental Crust Granulites: strongly metamorphosed and deformed— tonalite  10% quartz Strongly metamorphosed volcanics and sedimentary rocks

38. Formation of Archean Continental Crust Granulites: strongly metamorphosed and deformed— tonalite  10% quartz Greenstones: Strongly metamorphosed volcanics and sedimentary rocks

39. Formation of Archean Continental Crust Greenstones: What does the variation in composition suggest  subduction zone separation

40. Formation of Archean Continental Crust

42. Time line Hadean 4,600 MaSolar Nebula, Earth forms 4,500 MaMoon forms 4,400 MaAnoxic atmosphere forms 4,200 MaOceans start forming Archean 4,000 MaCrustal differentiation 3,000 MaBIF’s, atmospheric oxygen

43. QUESTIONS?