Earth Exact Age of Earth Geologic Dating Methods

Earth Exact Age of Earth: _______

Geologic Dating Methods I: Radioactive Decay http: //www. btinternet. com/~j. doyle/SR/Emc 2/decay_a-decay. gif

Geologic Dating Methods II: Known Rates of Radioactive Decay http: //people. hofstra. edu/j_b_bennington/2 cnotes/halflife. J PG

Geologic Dating Methods III: Radiocarbon half-lifes Ratios of Parent : Daughter Atoms

EARTH’S OLDEST ROCKS 4. 03 BYA (Acosta Gneisses) 3. 7 – 3. 8 BYA 3. 4 – 3. 5 BYA 3. 4 – 3. 6 BYA http: //pubs. usgs. gov/gip/geotime/age. html

Earth’s Oldest Known Rocks (Probably do NOT date to Earth’s Formation)

Geologic Forces (e. g. , Plate Tectonics)

Origin of Solar System

IRON METEORITES (Canyon Diablo) Age: 4. 53 -4. 58 BYA (U > Pb) http: //pubs. usgs. gov/gip/geotime/age. html

Canyon Diablo Crater (Near Flagstaff AZ)

LUNAR ROCKS Oldest Moon Rocks: 4. 4 -4. 5 BYA http: //pubs. usgs. gov/gip/geotime/age. html

Earth’s Origin (~ 4. 5 -4. 6 BYA)

500 Million Years After Origin of Earth (Artistic Rendition) http: //www. arcadiastreet. com/cgvistas/earth/images/earth_ancient_volcano_6 00. jpg

The Earth Cools (Artistic Rendition) http: //www. cartage. org. lb/en/themes/Sciences/Paleontology/Paleo zoology/Precambrian. htm

Atmospheric Oxygen Levels http: //ncbi. nlm. nih. gov

Predominantly Non-Oxidized Sediments

Ancient Evidence for Free Oxygen • Isua Rock (Greenland): ~ 3. 7 Billion Years Old • Metamorphosed Sediments • Abundant Free Uranium – Likely Only in Oxidizing Environment

Oxygen Liberating Process?

Ancient Fossil “Cyanobacteria” (3. 47 BYA) Apex Chert in Western Australia (Pilbara Formation) http: //www. cartage. org. lb/en/themes/Sciences/Paleontology/ Paleozoology/Precambrian/Apex. Chert. jpg

Fossil Stromatolites (3. 5 BYA)

Living Stromatolites (Shark Bay Australia)

Living Stromatolites (Cross-Section)

Fossil Stromatolites (with Fossil Microorganisms) Gunflint Chert – Ontario, Canada (2 BYA)

Origin of the Cell?

Origin of Organic Macromolecules?

Hypothesis I: Terrestrial Accretion (Miller – Urey Experiments 1950 s)

Hypothesis II: Meteoric and Cometary Infall of Organic Molecules formed Elsewhere (Present Day Meterites can contain 1% Organic Molecules)

Hypothesis III: Meteoric and Cometary Infall of Cells formed Elsewhere (e. g. , Mars)

Origin of Cell Membrane?

Hypothesis: Drying, Rehydrating of Tide Pools Fig. 2. 4 in Willis and Mc. Elwain 2002