EESA06H3 Chapter 4: EESA06 Chapter 4.pdf
Document Summary
Geophysics: application of physical laws and principles to a study of the earth; can look at the deep parts of the earth. Includes study of seismic waves, magnetic fields, gravity, and heat. What can we learn from the study of seismic waves. Studies of seismic waves have shown that: the crust is thinner beneath the oceans that beneath the continents, that seismic wavs travel faster in oceanic crust than in continental crust. Because of this velocity difference, it"s assumed that the two types of crust are made up of different rock types. Upper part of oceanic crust = basalt, lower part = gabbro. Continental crust = granitic, but the rock types making up continents are diverse. Felsic -> rocks high in feldspar + silicon (continental crust. Mafic -> rocks high in magnesium and iron (oceanic crust. Mohorovicic discontinuity: boundary that separates the crust from the mantle. Upper mantle = ultramafic rock (dense igneous rock)