6 - Geologic time(geochronology Earth is ~4.6 Ga(billion years old.compressed into 1 year Jan 1 Earth formed Feb 21 life formed Oct 25 complex organisms

6 - Geologic time(geochronology Earth is ~4.6 Ga(billion...

This preview shows page 1 - 5 out of 21 pages.

1 Geologic time (geochronology) Earth is ~4.6 Ga (billion years old) Jan 1: Earth formed Feb 21: life formed Oct 25: complex organisms Dec 7: reptiles evolved Dec 25: dinosaurs extinct Dec 31, 11:00 pm: homo sapiens appear Dec 31, 11:59:59.97: Columbus discovers Americas • typical university course: 0.0000011% of Earth ʼ s history ..compressed into 1 year Historical perspective Ussher, 1625: Sat evening, 22 Oct, 4004 BC (Bible genealogy; catastrophism ) Hutton, 1770-80’s: like, really 'old' Kelvin, 1890’s: 24-40 Ma ( cooling molten earth model) Joly, 1890’s: 90-100 Ma ( ocean salinity model) eo-1900’s: 3 Ma to 1600 Ma ( sediment deposition model) Becquerel & Currie, 1896: radioactivity discovered; first age estimate = 1640 Ma Geologic time (geochronology)
2 1) relative dating compare 2 or more entities to determine which is older 2) numerical dating specifying the actual number of years (± years) that have passed since an event occurred (also known as absolute age dating ) Geologic time (geochronology) We learned how to classify rocks.. now we need to classify time
3
4

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture