The document discusses several topics related to earth science including: 1. The instructor will post a problem set by Monday and it will be due on February 9th. 2. It clarifies that the angle of the Earth's tilt does not change during the year as seen from the sun's perspective. 3. Formulas are provided for calculating the sun angle at different latitudes and seasons based on the Earth's 23.5 degree tilt and the declination.

1. Announcements I will be writing PS #1 over the weekend, and posting it by Monday… It will be due Feb 9 th .

2. Clarification: The angle of Earth’s tilt does not change during the year! Views of the Earth from the Sun’s perspective It only looks that way from the sun’s frame of reference .

3. The axis is always parallel to itself.

4. Quiz 2!

5. 2. Sun Angle: insolation curves

6. 2. Sun Angle: insolation curves Winter Summer Autumn Spring Winter

7. Insolation 23.5 o axis tilt 0 o axis tilt

8. An Equation for the Sun Angle On an equinox Declination = 0 °

9. An Equation for the Sun Angle On an equinox Declination = 0 ° At the equator Lat = Sun angle = 0 ° 90 °

10. An Equation for the Sun Angle On an equinox Declination = 0 ° At the north pole Lat = Sun angle = 90 °N 0 °

11. An Equation for the Sun Angle On an equinox Declination = 0 ° At some latitude x Lat = Sun angle = x °N 90 °- x° x ° 90 °- x°

12. But then we have to adjust for declination! Equator is sub-solar point North pole tilted toward the sun North pole tilted away from the sun Equator is sub-solar point Summer Winter Fall Spring

13. But then we have to adjust for declination! Sun Angle = 90 °-x° Sun Angle = 90 °-x° Sun Angle = 90 °-x°-23.5° Sun Angle = 90 °-x°+23.5° Summer Winter Fall Spring

14. Final Formula Sun Angle at Noon = 90 ° - Latitude° + declination° Summer Note: this formula is for the angle with the southern horizon, so it makes the most sense to only use it in the Northern Hemisphere

15. Lithosphere: solid Earth

18. Grand Canyon Layers

20. A roadcut photo that I stole… WV maybe?

22. Roadcut near Moab, UT

23. A B C D Events: A deposited B deposited C deposited D deposited Faulting Erosion of Surface X Erosion of Canyon But in what order? Order of Events: D deposited C deposited B deposited Faulting Erosion of Surface X A deposited Erosion of Canyon X

24. Events: A deposited B deposited C deposited D deposited E deposited F deposited G deposited Folding Erosion of Surface X Order of Events: G deposited F deposited E deposited D deposited C deposited Folding Erosion of Surface X B deposited A deposited A B C D X E F G

25. Events: A deposited B deposited C deposited D deposited E deposited F deposited Folding Faulting Erosion of Surface X Erosion of Surface Y Order of Events: F deposited E deposited D deposited C deposited Folding Erosion of Surface Y B deposited Faulting Erosion of Surface X A deposited A B C D X E F Y

26. Events: Cooling of Granite A Deposition of Sandstones B, E, & I Deposition of Shales C & H Deposition of Limestone D & F Cooling of Basalt G Folding (Tilting) Faulting Erosion of surfaces X, Y, Z Formation of mesa Order of Events: 1 . A 9 . E 2 . X 10 . F 3 . B 11 . Z 4 . C 12 . G 5 . D 13 . H 6 . fold/tilt 14 . I 7 . Y 15 . mesa 8 . fault