GEOLOGY Quizz questions

II. Planet Earth Structure (Ch 1)

A. Interior Structure

Earth is made up of layers. The layers of the Earth formed > 4 billion years ago.

LAYERS DIVIDED BY
PHYSICAL PROPERTIES	CHEMICAL COMPOSITION
Atmosphere 97% within 29km -gas Hydrosphere ave. depth ~5km -liquid Lithosphere - brittle solid --- 100 km----(60mi) Asthenosphere- plastic (non-rigid) solid --- 350 km---- (210mi) Mesosphere - rigid solid --- 2883km----(1730 mi) Outer Core - liquid Inner Core - solid metal -center - 6371km(3823 mi)----	N2, O2 water Crust - high Si rock ---~8-70km----(5 - 42mi) Mantle - high Mg rock --- 2883km--------(1730 mi) Core - iron

Crust: continental 20-70km thick, average: ~35km (~12 - ~42 mi) (~21 mi); oceanic ~8 km thick (min ~5mi)

Isostasy: read p.329-331

B. Plates and Plate Tectonics (Chapter 2)

A plate is a section of lithosphere which moves as a unit. - internally rigid Deformation occurs at plate boundaries. àresultsin earthquakes Earthquake map:

Plate map:

Plate tectonics has to do with the motions and deformation of platesè

3 types of plate boundaries

1. Divergent margin: - moving apart

Plate A ç

Plate B è

spreading center: mid-ocean ridge

2. Convergent margin- moving towards each other

Plate C è

Plate D ç

subduction zone oceanic trench ==> Aleutian trench and Islands= island arc

3. Transform-fault Margin- moving past each other, side-by-side

Plate E é

Plate F ê

example: San Andreas and Hayward Faults, California

C. Driving Force for Plate Tectonicè Why do plates move? Convection - heat within Earth "trying" to get out. è Speed: 2cm/yr - 20cm/yr