Announcements

1
Announcements

• Zachs Friday lab
• Oops!
• Handouts available here now
• If YOURE not here, get from Zach Monday or
  Tuesday
• Due in lab next Friday
• Class Web page
• Inaccessible due to hacking
• Announcements on PowerPoint Page
• Test scores on PowerPoint page also

2
Pluvial Lakes
3
Sea Levels

• Oceans are closed-basin lakes!
• Sea level ?constant!
• Change with ice volume and other factors

4
Long-term Sea Levels

• 10,000 years
• 500,000 years

5
Future Sea Levels

• Geologic context
• Current data
• Future Models

6
Pleistocene Climates and Change

• Record from
• Ice cores/chemistry
• Lake sediments/biota
• Ocean sediments/biota
• Cycles!
• 100,000 years
• 40,000 years
• 20,000 years
• Cause?

7
Astronomical cycles

• Eccentricity of the orbit
• 100,000 yr
• Tilt
• 40,000 yr
• Wobble
• 20,000 yr
• Affects seasonal insolation
• Hemispheres!

8
Weather
9
Soils and Their Classification
10
Whats a soil?

• Pedon (3-D)
• Profile (2-D)
• Horizons (layers)
• O, A, E, B, C, R
• Solum
• B horizon and above
• Farm soils, not fields

11
Soil formation

• Hans Jennys 5 soil-forming variables
• Parent mat.
• Topography
• Organisms
• Climate
• Time

12
Parent material

• Soil texture
• Triangle (100)
• Sand
• Silt
• Clay
• Affects
• Nutrients
• Water
• Strength

13
Soil Classification

• U.S. Soil Taxonomy
• Descriptive
• Agricultural
• Started (1975) with ten soil orders
• Added Andisols and Gelisols since then
• Can interpret process

14
(No Transcript)
15
Soils of the World

• Another map, similar to ?
• Note areas of nonsoils (dont support life)

16
Soil occurrence

• Compare U.S. and world
• Discuss in order of U.S. frequency

17
Soils of the United States

• Why only ten orders listed?
• Whats missing?
• What controls U.S. soil patterns?
• P.M.
• Topography
• Organisms
• Climate
• Time

18
Mollisols 22

• Deep, rich A horizon
• Prairie soils
• Global distribution
• Climate?
• U.S. distribution
• Suborders

Bs - Steppe
19
Alfisols 14

• E horizon (leaching)
• Forest soils
• Global distribution
• Climate?
• U.S. distribution
• Suborders

D-Humid Cont.?
20
Entisols 12

• No B horizon
• Young soils - deposits
• Global distribution
• Climate?
• U.S. distribution
• Suborders

No - time
21
Ultisols 10

• Deep, leached soils
• Humid soils
• Global distribution
• Climate?
• U.S. distribution
• Suborders

C Mild midlat.
22
Inceptisols 9

• Weak B horizon
• Young soils - hillslopes
• Global distribution
• Climate?
• U.S. distribution
• Suborders

No - topography
23
Aridisols 9

• Almost no A horizon
• Desert soils
• Global distribution
• Climate?
• U.S. distribution
• Suborders

Bw - Desert
24
Gelisols 7.5

• Frozen soils
• Permafrost soils
• Global distribution
• Climate?
• U.S. distribution
• Suborders

D/ESubarc/Tundra
25
Spodosols 3.3

• Rich B horizon
• Moist soils leached E
• Global distribution
• Climate?
• U.S. distribution
• Suborders

D Humid cont.?
26
Andisols 1.7

• Soils in volcanic ash
• Andesitic soils
• Global distribution
• Climate?
• U.S. distribution
• Suborders

No parent material
27
Vertisols 1.7

• Mixed soils
• Soils in (certain) clays
• Global distribution
• Climate?
• U.S. distribution
• Suborders

NO Parent material
28
Histosols 1.3

• Organic soils
• Bog/marsh/peat soils
• Global distribution
• Climate?
• U.S. distribution
• Suborders

D Severe cont.?
29
Oxisols 0

• Residual soils
• Soils w/ only oxides left
• Global distribution
• Climate?
• U.S. distribution
• Suborders

A Tropical!
30
My Favorite Soil Petrocalcic Paleargid
A
Bt

• Minimal A horizon (Aridisol)
• Clay accumulation in the B horizon (argillic)
• Strong horizon development old (paleo)
• Accumulation of carbonate (calcic)
• Cementation of carbonate (rock-like petro)

Bk
calcic
Petro
id
arg
Pale
31
Soil degradation

• Erosion salinization