Lecture 1 (Intro)

And some rin uphill and down dale,Knapping the chucky stones to pieces wi’ hammers,

Like sae mony roadmakers run daft –They say it is to see how the warld was made.

- Sir Walter Raleigh

Of Igneous rocks and volcanoes

Webpage for course (daytime)

Webpage for course (nighttime)

Difference between rocks and minerals

Three types of rocks:

Minerals in igneous rock

Fig. 3.2Minerals distributed randomlyCrystals grow into one another

Continental vs. oceanic crust

Mineral composition of earth crust

Continental crust

Feldspar 58%

Chain silicates 13%

Quartz 11%

Micas (incl. clays)10%

Calcite, Gypsum,

Halite 3%

Olivine 3%

Misc. 2%

Oceanic crust

Olivine 30%

Chain silicates 30%

Plagioclase

feldspars 40%

Types of Igneous environments Volcanic (extrusive)

fine-grained

Plutonic (intrusive)

coarse-grained

Mineral compositions Continental Intermediate Oceanic

Volcan

ic Plu

tonic

Three types of volcanoes

due to mineral characteristics

Continental Composite Oceanic

shield

Three types of volcanoes

pyroclastic composite

< http://www.clas.ufl.edu/users/pciesiel/

gly3150/mt_st_helens2.gif >

< http://upload.wikimedia.org/wikipedia/commons/0/

06/Mauna_Kea_cinder_cone.jpg >

Fig. 3.14b

Fig. 3.15a

obsidian

pumice

History of a volcano

Eroded volcano – volcanic neck

http://www.destination360.com/north-america/us/wyoming/devils-tower-national-monument

Example: Devil’s Tower, Wyoming

Volcanic crater - caldera

http://www.dustydavis.com/longride/2004

Example: Crater Lake, Oregon

“Ring of Fire”

Where do composite volcanoes occur?

Fig. 4.33

Unusual volcanoes - kimberlites

http://volcano.oregonstate.edu/book/export/html/170&usg

Associated with hotspots

Unusual volcanoes - kimberlites

Loper and McCartney hypothesis of dinosaur extinction

http://www.astro.virginia.edu/class/oconnell/astr121/marsImages.html&usg