The GeosphereHonors BiologyChapter 3

DefinitionThe solid part of the earth, including all rock, soil, and sediments6378 km radiusDetermined by seismic studies

CompositionCrust 70 km thick; light elements; brittle (1% of mass)Mantle 2900 km thick; medium density materials; fluid (64% of mass)Core 3400 km radius; densest metals (35% of mass)

5 Layer StructureLithosphere 15-300km; cool and rigid; crust and upper mantle; divided into the tectonic plates

5 Layer StructureAsthenosphere- 250km; plastic layer that can flex and allows plates to move on it

5 Layer StructureMesosphere 2550km; lower mantle

5 Layer StructureOuter core 2200km; liquid nickel and iron

5 Layer StructureInner core 1228 km radius; solid nickel and iron

Plate TectonicsInternal forces move platesDivergent, convergent, and transform fault boundariesCauses mountain building, seafloor spreading (below), earthquakes and volcanism

Mountain Building

EarthquakesFault crack along which movement occursQuake vibrations from movementMagnitude amount of energy released, measured by Richter Scale (2.0 felt and 9.5 largest measured); 7.0 is 31.7 times more energy than 6.0Majority occur on crustal plate boundaries

VolcanoesMountain built from magma/lavaOften near tectonic plate boundaries that are separating or collidingOccur on land and under the sea

Erosion of the GeosphereRemoval and transport of materialsRemovable because of weatheringSmooths and rounds featuresDone by numerous agents: wind, water, gravity

The Wai'anae and Ko'olau mountain ranges no longer have rounded tops. They are two extinct jagged mountain ranges that have been cut into by streams and rain washing away rocks and dirt. This is called erosion.

The End (for now)