• Today– Pre Cambrian Geology– DUE: Coastal Geology Project

• Monday– Paleozoic Tectonics– LAB Geology of North America– DUE: Choice of Fossil for Fossil Poster

• Next Wednesday– Paleozoic Climate & Life– Mesozoic Tectonics

Outline of Pre-Cambrian

Time

• Age & Origin of Earth

• Oldest Rocks & Minerals

• Archean Tectonics

• Origin of Atmosphere & Life

The Oldest Terrestrial Rocks: Acasta Gneiss4.0 billion years old!

Source: Sam Bowring/MIT

The Oldest Rocks on Earth : Meteorites4.5 billion years old!

Source: http://www-curator.jsc.nasa.gov/outreach1/expmetmys/slideset/Slides16-20.htm http://pds.jpl.nasa.gov/planets/captions/smallbod/iron.htm

01_13and15.jpg

01_Featured_Art.jpgZoomable ArtPC Mac

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Hadean: Hell on Earth? (Fig. 13-4)

Oldest Rocks & Minerals

Archean Crust

World’s Oldest Rock: Acasta Gneiss 4.0 b.y. (Fig. 12-25)

Source: http://www.gly.fsu.edu/~salters/GLY1000/13Age_of_Earth/Slide19.jpg

World’s Oldest Mineral Grain: Zircon form Jack Hills Australia

Source: http://www.geology.wisc.edu/zircon/Earliest%20Piece/Earliest.html

Australian Craton

Source: http://earthobservatory.nasa.gov/Study/Zircon/

Jack Hills Metaconglomerate

Source: http://www.geology.wisc.edu/zircon/Earliest%20Piece/Earliest.html

World’s Oldest Sedimentary Rock: Isua Metasediments 3.8 b.y.

Source: http://news.bbc.co.uk/2/hi/science/nature/3321819.stm

Source: http://www.geology.wisc.edu/zircon/Earliest%20Piece/Earliest.html

Archean Tectonics

Why so little Archean Crust?

Granulite/gneiss and greenstone belts

Granulite Greenstone Belts

Archean Pillow Basalts

Formation of greenstone beltsArc Model

Formation of greenstone beltsArc Model (Fig. 13-5)

Pre-Cambrian of North America

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For Monday 5/17

• On-line Readings– Early and Late Paleozoic Events