Title: Intro to Geology
1Intro to Geology
- EARTHS CRUST
- and
- INTERIOR
Summer 2008
2Earth
- 4.55 Billion years old
- Average diameter 12,742 km
You are here
3a still-active planet
significant heat-driven motions above and below
the surface
615
4Lecture 1 Density and Gravity
- A geologists view of mountains
5Purpose
- to explain Earths surface form
- to teach scientific method and logic
- physical geology
- rocks and minerals
-
Img_0179
6Sugarloaf Peak, Box Springs Mountains
molten rock reservoir beneath a volcano i.e. must
have solidified and been uplifted many kilometers
7Sierra Nevada and Owens Valley
- a chain of ancient magma chambers
originally below a line of volcanoes like the
Cascade Range i.e. volcanoes can be turned off
and worn off the face of Earth
8Hawaiian Islands
9Hawaii cont
10Mt. Ruapehu
1995
Ruapehu
Ngauruhoe
eruptions not always good for conical shape
Tongariro
- active volcanoes in a line
11Mt. St. Helens, WA
May 17, 1980
12Mt. Ngauruhoe, New Zealand
13Mt. Ngauruhoe, New Zealand
i.e. young, not yet worn away active?
dormant?
14Mt. Doom, Mordor
- volcano with conical shape
15Other Volcano Shapes
small dome of viscous lava
Hawaii
huge flat shield volcano
Puu Heewa
explosions build cones lava builds shields and
domes
tiny cinder cones
fluid lava flow
- Shape is a clue to eruptive style
16There are chains of volcanoes on the ocean floor
too!
17Marble Mountains, Mojave Desert (old Route 66)
- ancient sea-floor deposits, resting on rocks of
ancient magma chamber
18Marble Mountains, Mojave Desert (old Route 66)
- ancient sea-floor deposits, resting on rocks of
ancient magma chamber
i.e. oceans may expand and contract ocean
floor may be tilted and uplifted onto continent
19The French Alps
- more layered oceanic sediment
i.e. many mountains are constructed from ocean
floors
20Mt Everest, Himalaya Mountains
- more layered oceanic rocks
i.e. uplift may reach nearly 9 kilometers above
sea level
21Monument Valley, Arizona/Utah
- horizontal layered sediments
i.e. requires huge volumes to be worn away
(eroded) requires long-term stability
22The white cliffs of Dover
23Just a Place to Ski and Climb?
24The Steinplatte, Austria
i.e. sea floor was uplifted, then the soft
mud-rocks around the reef were worn away
25Glacier National Park
faces of peak carved by ice of glaciers flowing
by i.e. evidence of recent climate
change
26(No Transcript)
27Patterns for mountain formation?
- observations mountains form
- at volcanoes (on land and at sea)
- from the uplifted roots of volcanoes
- by pushing rocks up above sea level
- by folding/compressing rocks
- by erosion of soft rocks by rivers
- by erosion of hard rocks by glaciers
heat from below
tectonics
surface processes
- these factors are interrelated, as we shall see
28Next up
Earths Crust and Interior