Earth’s Geologic Processes Earth is a dynamic planet

The Earth Is a Dynamic Planet 1.Three major concentric zones of the earth a. core inner most zone; solid inner mass surrounded by molten material b. mantle Including the asthenosphere c. crust outermost and thinnest Continental crust – underlies continents including continental shelf Oceanic crust: 71% of crust 2. Lithosphere - crust & outermost part of the mantle (above asthenosphere)

Major Features of the Earth’s Crust and Upper Mantle Fig. 14-2, p. 348

Tectonic Plate Boundaries Three types of boundaries between plates: a. Divergent boundaries Move apart Magma Oceanic ridge b. Convergent boundaries Collide together Subduction zone Trench c. Transform boundaries: Slide past each other San Andreas fault

Oceanic and Continental Plates 1. When oceanic plate collides with continental plate continental plates rides on top of oceanic plate & oceanic plate is pulled into mantle (subduction) 2. When oceanic plates move apart: Magma flows up through cracks and creates trenches EX: Mid-Atlantic Ridge) 3. When oceanic plates collide: Trenches form at the boundary between the plates 4.When continental plates collide: Mountains form EX: Himalayans are a result of Indian plate being pushed into Tibet Be able to locate these areas on a world map!

Earth’s Major Tectonic Plates Fig. 14-4, p. 349

Himalayan Mountains Results of Indian plate colliding with Tibet plate

Volcanoes 1.Occur where magma reaches earth’s surface through a central vent 2.Many occur along plate boundaries 3.Ring of Fire 4.Intraplate volcanism a.volcanism within the plate interiors b.Called hotspots c.Most hotspots are thought to be underlain by a large plume of anomalously hot mantle d.The Big Island of Hawaii is one example located within the Pacific Plate

1.Nazca plate is colliding with the South American plate – creating Andes Mtns 2.Cocos plate is crashing into the North American – creating volcanoes 3.Pacific, Juan de Fuca, and Gorda plates have built the Cascades (Mt. St. Helens) 4.Subduction of the Pacific plate under the Eurasian plate is responsible for Japanese islands and volcanoes (Mt. Fugi)

Volcanisms and Intraplate Hotspots Big Island of Hawaii and Yellowstone volcanoes formed as intraplate hotspots

Vocabulary of Earthquakes

2 Earthquakes September 24, 2013 Magnitude 7.7 Pakistan – Pakistan's remote south-west province. – Killed at least 208 people – Many houses were flattened and thousands of people have spent the night in the open. September 25, 2013 Magnitude 7.0 Peru – Centered off Peru's sparsely populated southwestern coast – minor damage and light injuries were reported.

Richter Scale An earthquake with a magnitude of 7 is 1000 times stronger than one with a magnitude of 4

Earthquake Risk in the United States Figure 16, Supplement 8

World Earthquake Risk Figure 17, Supplement 8

Earthquakes on the Ocean Floor Can Cause Huge Waves Called Tsunamis Tsunami, tidal wave – Travels several hundred miles per hour Detection of tsunamis – Buoys in open ocean December 2004: Indian Ocean tsunami – Magnitude 9.15 and 31-meter waves at shore – Role of coral reefs and mangrove forests in reducing death toll

Formation of a Tsunami and Map of Affected Area of Dec 2004 Tsunami Fig. 14-8, p. 352

Rock Cycle Change of rocks from one type to another type Slowest of all of Earth’s cycles Rocks verses Minerals Rock: composed of 1 or more minerals Minerals: solid chemical substances with uniform structures that forms under specific temperatures & pressures

Formation of Rocks Rock: forms when magma from Earth’s interior reaches the surface, cools, and hardens At surface, rock masses are broken up, moved, and deposited elsewhere New rock can be formed from deposited material Magma is the original source of all rock

Igneous Rocks Both form directly from magma Basaltic:  Dark colored  Dominant rock type of oceanic plates Granitic  Lighter colored  Dominant rock type of continental plates  Forms sand when it breaks down  Soils are permeable (helps move water through) Form bulk of earth’s crust but covered with sedimentary rock Basaltic Rock Granitic Rock

Sedimentary Rock Forms when sediments (mud, sands, & gravel) are compressed by over-lying sediments Occurs over long periods of time when environments are buried (creates pressure on material below) Rock may be very uniform in composition or very heterogeneous

Metamorphic Sedimentary, igneous, or metamorphic rock are subjected to high temperatures & pressures  May cause partial melting Pressure causes great physical and chemical changes in rock  May reshape internal crystalline structure Pressure caused by overlying rock layers or by plate tectonics EX: slate, marble, anthracite limestone marble

Physical Weathering Mechanical breakdown of rocks and minerals Caused by wind, water, or temperature changes Coarse grained or metamorphic rock tends to weather more quickly over time Plant roots (trees) break apart rock Increases the surface area for chemical weathering

Chemical Weathering Lichen slowly release acid onto rock A plant’s roots or animal cells undergo cell respiration and the CO 2 produced diffuses into soil, reacts with H 2 O & forms carbonic acid (H 2 CO 3 ). Acid rain also reacts with rock and breaks it down Lichen growing on rock

Erosion Physical removal of rock fragments such as sediment, soil, and other particles from the ecosystem Caused by:  Non-living things: wind, water, and ice transport soil & minerals down slope  Living things such as animals that burrow under soil Erosion is a natural process (carves canyons) Erosion by stream flow