What is the Earth System? The atmosphere (Air) extends up from the Earth surface for several hundred kilometers. The biosphere (Life) is all living things, from single-celled bacteria to plants and animals. The geosphere (Land) includes all minerals, rocks, molten rock, sediments, and soils The hydrosphere (Water) includes the ocean, rivers, lakes, streams, groundwater, water vapor. (The cryosphere (Ice) is the frozen part of the Earth system and includes snow, glaciers, and sea ice.)

All systems are connected “When we try to pick out anything by itself, we find it hitched to everything else in the universe.” John Muir “My First Summer in the Sierra” 1911

Energy Starting Point It all starts at the Sun Energy from the Sun is the ultimate source of almost all energy in the Earth system!

Geology – study of the earth

I. Earth’s Structure Layers of the Earth– 1. crust – (.5%) – top layer; thinnest under oceans (Lithosphere) 2. Mantle (67%) - a. Lithosphere - (rigid portion - plates) b. Asthenosphere – flows due to added pressure 3. Outer Core – liquid; (iron & nickel) 4. Inner Core – solid; (iron & nickel)

Layers of the Earth – temp & pressure increase as you move down to center

B. Rocks & Minerals – solid portion of the crust 1. Mineral – solid, inorganic material with the same chemical make-up, crystalline structure, & specific properties like color, hardness; ex. salt, mica, pyrite, quartz, diamond 2. Rock – solid, inorganic material made up of 2 or more minerals

3. Types of Rocks a. Igneous – crystalline solids which form directly from the cooling of magma/lava; ex. basalt, pumice, granite b. Sedimentary - the accumulation/layering & compacting of small broken off pieces of pre-existing rocks; sandstone, limestone, shale c. Metamorphic – rocks subjected to different temperatures & pressures to “change form”; ex. marble, slate, quartzite

Types of Rocks Igneous Sedimentary Metamorphic Marble Slate Pumice Sandstone

4. Rock Cycle

II. Plate Tectonics Theories 1. Continental Drift – 1929 – Alfred Wegener – proposed continents were originally 1 & then moved apart

2. Seafloor Spreading – 1960s – Harry Hess -seafloor itself moves (and carries the continents with it; process that occurs where 2 plates meet - new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. )

B. Earth’s Plates - composed of 7 (8) large or 30 total sections of the lithosphere (upper mantle + crust) that move around on the plastic-like asthenosphere: 2 – 10 cm/yr at different directions & speed

C. Plate Movement The heat from the core of the earth reaches the mantle. Heat is transferred to the fluid layer and the resulting convection currents cause the plates to move. Plate Boundary – place where 2 plates meet & move

D. Types of Plate Movement 1. Convergent Boundary - Place where plates crash or crunch together; can form mts., volcanoes, earthquakes

2. Divergent Boundary - Place where plates are coming apart; rifts or valleys form here (Great Rift Valley in Kenya or the rift near the Rio Grande; can form volcanoes or earthquakes

3. Transform Boundaries – Place where plates slide past each other; cause lots of earthquakes

E. Results of Plate Movement -Volcanoes & Earthquakes Tectonic Plates, Volcanoes & Earthquakes

III. Forces on Earth to cause Landforms (combination) Destructive Forces – processes that destroy landforms; 1. 2 types: weathering (slow) and Erosion (fast) 2. Ex. landslides, volcanic eruptions, earthquakes (faulting), floods B. Constructive forces: forces that build up an existing landform or create a new one. 1. caused by: water, gravity, wind and glaciers. 2. Ex: deposition of sediment, landslides, volcanic eruptions, floods

C. Types of Forces at Work 1. Weathering – breaks rocks into sediments a. Mechanical weathering: the breaking of rock into smaller pieces by forces due to gravity, ice, plant roots, or other physical forces. b. Chemical Weathering: the changing of materials in a rock by chemical processes.

2. Erosion – destructive movement of materials away from one place by wind, water, ice, & gravity Water erosion wind erosion glacial erosion

3. Deposition: the placing of materials in a new place (constructive force). Ex. Sandbars River Deltas – at mouth of Mississippi River Deposition by volcanoes

F. Examples of Forces at Work Landslides – gravity quickly pulls rock & dirt downhill 2. Floods – great flow of water over (usually dry) land

3. Earthquakes - A sudden movement of the earth's crust caused by the release of stress accumulated along geologic faults or by volcanic activity 4. Volcanic Activity - rupture in the crust, which allows hot magma, volcanic ash and gases to escape from the magma chamber below the surface

III. Applied Geology Economic geology – locate & manage earth’s natural resources – ex. petroleum, coal, minerals B. Mining geology – extraction of minerals from the Earth (petroleum geology – petroleum & natural gas) C. Engineering geology –works to design structures based on the features of the Earth

4. Environmental geology – looking at environmental issues related to natural habitat & water issues 5. Natural hazards geology – study of the natural hazards of earth to enact safe building codes & warning systems used to prevent loss of property & life