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Time Scales

Time Scales. Time Perspectives Chronostratigraphy Geologic Time Scale Radioactive Decay Radiometric Dating Pilot Knob Lab. Text: Manual, p. 3, 29, 131-136; Boggs, Ch. 18. Time Perspectives. Catastrophism . http://www.meteorcrater.com/. Time Perspectives.

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Time Scales

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  1. Time Scales • Time Perspectives • Chronostratigraphy • Geologic Time Scale • Radioactive Decay • Radiometric Dating • Pilot Knob Lab Text: Manual, p. 3, 29, 131-136; Boggs, Ch. 18

  2. Time Perspectives Catastrophism http://www.meteorcrater.com/

  3. Time Perspectives Uniformitarianism

  4. Time Perspectives How Much is a Billion? save $100 / day ? how may years to save 1 billion $

  5. Time Scales The Geologic Time Scale: an arrangement of the earth’s geologic record into a standard sequence of units. • relative age order • boundaries based on fossils, lithology, polarity • absolute ages by radiometric dating

  6. Time Scales • Time Perspectives • Chronostratigraphy • Geologic Time Scale • Radioactive Decay • Radiometric Dating • Pilot Knob Lab Text: Manual, p. 3, 29, 131-136; Boggs, Ch. 18

  7. Chronostratigraphy Chronostratigraphy: establish time relationships among rock units Geologic Time Units • Geochronologic Units - time interval • Chronostratigraphic Units - rock body representative of time interval

  8. Chronostratigraphy Geochronologic Unit – time interval Eon Era *Period Epoch Age Chron

  9. Chronostratigraphy Geochronologic Unit – time interval Eon – Phanerozoic Era – Mesozoic *Period – Cretaceous Epoch – Late Cretaceous Age – Campanian Chron – Orbitoides tissoti

  10. Chronostratigraphy Chronostratigraphic Unit – rock bodies representative of time interval Eonothem Erathem *System Series Stage Chronozone

  11. Chronostratigraphy Chronostratigraphic Unit – rock bodies representative of time interval Eonothem Erathem *System – Cretaceous System Series – Upper Cretaceous Series Stage Chronozone

  12. Chronostratigraphy Period Subdivisions System Subdivisions Early and Late Lower and Upper

  13. Time Scales • Time Perspectives • Chronostratigraphy • Geologic Time Scale • Radioactive Decay • Radiometric Dating • Pilot Knob Lab Text: Manual, p. 3, 29, 131-136; Boggs, Ch. 18

  14. Geologic Time Scale

  15. (Harland et al., 1990)

  16. Maastrichtian Campanian Santonian Coniacian Turonian Cenomanian Albian Aptian Barremain Hauterivian Valanginian Ryazanian Geologic Time Scale Ages of Cretaceous Period Even More Detail…

  17. Geologic Time Scale Precambrian Events millions of years ago after (http://www.ucmp.berkeley.edu/precambrian/precambrian.html)

  18. 3.8 4.0 3.5-3.7 3.5 3.6 4.4 Geologic Time Scale World’s Oldest Rocks (Age in Billion Years)

  19. Geologic Time Scale Precambrian Events millions of years ago after (http://www.ucmp.berkeley.edu/precambrian/precambrian.html) www.calm.wa.gov.au/national_parks/hamelin_pool_mnr.html

  20. Geologic Time Scale Precambrian Events millions of years ago after (http://www.ucmp.berkeley.edu/precambrian/precambrian.html) http://www-rohan.sdsu.edu/~rhmiller/depositionfeatures1/

  21. Geologic Time Scale Precambrian Events millions of years ago after (http://www.ucmp.berkeley.edu/precambrian/precambrian.html) http://www.ucmp.berkeley.edu/vendian/pter.gif

  22. Geologic Time Scale Amphibians Land Plants Animals with Hard Parts http://www.inhandmuseum.com/images/Geologic_Timeline.GIF http://palaeo.gly.bris.ac.uk/Palaeofiles/Lagerstatten/Burgess/gallery.html

  23. Primates Break-up of Pangea Dinosaurs Amphibians Land Plants Animals with Hard Parts http://www.inhandmuseum.com/images/Geologic_Timeline.GIF

  24. Human Civilizations Ice Ages Grasses Primates Break-up of Pangea Dinosaurs Amphibians Land Plants Animals with Hard Parts http://www.inhandmuseum.com/images/Geologic_Timeline.GIF

  25. Relative Time Absolute Ages

  26. Time Scales • Time Perspectives • Chronostratigraphy • Geologic Time Scale • Radioactive Decay • Radiometric Dating • Pilot Knob Lab Text: Manual, p. 3, 29, 131-136; Boggs, Ch. 18

  27. Radioactive Decay radioactive radiogenic Parent Daughter • loss of particle from nucleus • statistical behavior of population • constant decay rate

  28. Radioactive Decay Some Types of Radioactive Decay Beta Decay: N  P and lose e- Alpha Decay: lose 2P + 2 N AGI, 1999

  29. Radioactive Decay 87Rb  87Sr

  30. Radioactive Decay Half Life: The time required for half of the amount of parent to decay to daughter “Close the Box”

  31. Radioactive Decay 100 80 60 40 20 0 M&M Experiment Number of Parents 0 1 2 3 4 Number of Half Lives

  32. Radioactive Decay

  33. Time Scales • Time Perspectives • Chronostratigraphy • Geologic Time Scale • Radioactive Decay • Radiometric Dating • Pilot Knob Lab Text: Manual, p. 3, 29, 131-136; Boggs, Ch. 18

  34. Radiometric Dating Parent-Daughter Pairs

  35. Radiometric Dating Analytical Methods isolate parent and daughter measure amount of parent and daughter

  36. Radiometric Dating What event are you dating? volcano2_und_nodak_edu NPS

  37. Radiometric Dating Considerations • choose right mineral • assume a closed system zircon

  38. Radiometric Dating 14C-dating Concerns variable production rates of 14C old C in oceans selective uptake of 14C

  39. Radiometric Dating absolute date Calibrate the Time Scale relative age biozone absolute date relative age biozone http://www.talkorigins.org/faqs/dating.html

  40. Radiometric Dating Assign ages to relative time period boundaries USGS

  41. Time Scales • Time Perspectives • Chronostratigraphy • Geologic Time Scale • Radioactive Decay • Radiometric Dating • Pilot Knob Lab Text: Manual, p. 3, 29, 131-136; Boggs, Ch. 18

  42. Pilot Knob Lab • basalt • pyroclastics

  43. Pilot Knob Lab

  44. Pilot Knob Lab Kavachi, Solomon Islands NOOA

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