Earth Science

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Earth Science
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Earth Science

• Earth Science
• Earth science is the study of planet Earth,
  including its structure, components, and
  essential characteristics.
• Earth science fields of study are further
  classified according to specific topics, such
  as
• geography study of Earths landforms, features,
  climates, and environment.
• geology study of Earths crust, including its
  composition and development.
• meteorology study of Earths atmosphere,
  including its composition and weather patterns.
• oceanography study of Earths water, including
  fresh and salt water.

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Earth Science

• The multidisciplinary Earth sciences are
  generally classified according to one of four
  general spheres, or domains, of Earth
• lithosphere the outermost layer of rocky land.
• hydrosphere the combined water (solid, liquid,
  and gas) found on and under the surface.
• atmosphere the enveloping layer of protective
  gas around the surface.
• biosphere the region that supports and nurtures
  life (includes portions of lithosphere,
  hydrosphere, and atmosphere).

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Earth Science

• Geologic Calendar
• Represents scientific understanding of age and
  history of Earth.
• Primarily divided into two eons Precambrian and
  Phanerozoic.

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Earth Science

• PRECAMBRIAN
• Lasted from formation of Earth (about 4.6 billion
  years ago) to 570 million years ago.
• Abundant life forms algae, bacteria, fungi,
  worms, and sponges.

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Earth Science

• PHANEROZOIC
• Lasted from 570 million years ago until the
  present.
• Divided into three eras
• Paleozoic
• Mesozoic
• Cenozoic.

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The Three Eras of the PHANEROZOIC

• Paleozoic
• 570245 million years ago
• Lack of fossil preservation
• Diversity of life relatively unknown

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The Three Eras of the PHANEROZOIC

• Mesozoic
• 245 - 66 million years ago
• First mammals and flowering plants appear
• Dinosaurs flourish

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The Three Eras of the PHANEROZOIC

• Cenozoic
• 66 million years ago until the present
• Mammals diversified and ruled the surface of
  Earth
• Primates first appeared

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The Lithosphere

• Elements
• Collection of atoms of the same type.
• Simplest form of matter that
• Cannot be formed from simpler substances.
• Cannot decompose into simpler substances.
• Organized on the Periodic Table of the Elements
• Periodic Table contains 115 elements
• 92 elements found naturally.
• 23 elements created artificially in laboratories.

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The Lithosphere

• Minerals
• Naturally occurring, inorganic, solid substances.
• Formed when groups of atoms bond together.
• Characterized by composition and arrangement of
  atoms.
• Classified by physical properties (composition)
• Crystal habit, hardness, color, cleavage, luster
• Classified by composition and crystal structure
  (arrangement of atoms)
• Native elements, silicates, carbonates, halides,
  oxides, sulfides, sulfates

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The Lithosphere

• Rocks
• Collections of minerals.
• Classified into three natural types
• igneous,
• metamorphic
• sedimentary
• Distinguished by rock structure and mineral
  composition.

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The Lithosphere

• IGNEOUS ROCK
• Forms as minerals from magma (hot, liquid rock)
  crystallize.
• Originates deep inside Earth.
• Is pushed to surface by magma.
• Has a texture that is determined by its rate of
  cooling.

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The Lithosphere

• METAMORPHIC ROCK
• Forms as a result of extreme pressure and/or
  temperature.
• Can alter and change pre-existing, older rocks.
• Can begin as either igneous or sedimentary rock.

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The Lithosphere

• SEDIMENTARY ROCK
• Originates as detritus (loose sediment) formed
  from wind and water erosion.
• Forms as detritus accumulates and compacts to a
  solid mass.

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Layers of the Earth

• Layers of the Earth
• Earth is generally divided into three regions
  crust, mantle, core.
• These layers are separated by density.

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Layers of the Earth

• CRUST
• Acts as Earths hard Outer shell.
• Divided into two parts by density continental
  and oceanic.
• Continental
• Located beneath surface not covered with water
• Approximately 3040 km thick o much older than
  oceanic crust
• Consists mostly of igneous rocks o composed
  mostly of granite and basalt
• Oceanic
• Located beneath the oceans o approximately 611km
  thick
• Composed mostly of basalt

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Layers of the Earth

• MANTLE
• located under crustis almost 3,000 km thick.
• contains nearly 80 percent of Earths total
  volume.
• is divided into inner and outer mantle.
• has temperatures ranging from 2,500F5,400F
• heat from core travels through the mantle to the
  crust in circles called convection currents.
• Convection currents are responsible for plate
  tectonics.

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Layers of the Earth

• CORE
• located approximately 3,000 km beneath surface.
• divided into inner and outer core.
• outer core composed of molten nickel-iron.
• inner core is solid because of intense pressure.
• temperatures reach 6,700F.
• Outer core spins around inner core with rotation
  of Earth.
• Earths magnetic field is generated by rotation
  of ions in molten core.

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Plate Tectonics

• Plate Tectonics
• Lithosphere broken into large, rigid plates.
• major plates African, North American, South
  American, Eurasian, Australian, Antarctic,
  Pacific
• minor plates Arabian, Nazca, Philippines
• Seismic energy from two plates interacting with
  each other causes earthquakes. Intensity of
  earthquakes measured on the
• Richter scale
• categorizes earthquakes on a numeric scale.
• each increase in number represents a 30x increase
  in energy release.
• Plates interact by colliding into, moving away
  from, and rubbing against each other. These
  interactions create earthquakes, volcanoes,
  mountain ranges.

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Plate Tectonics

• CONVERGENT PLATE BOUNDARIES
• Occur when plates collide or move into each
  other.
• Results include earthquakes, Andes and Himalayan
  mountains.

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Plate Tectonics

• DIVERGENT PLATE BOUNDARIES
• Occur when plates move away from each other.
• Results include oceanic ridges, East African rift
  valley, Rio Grande rift.

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Plate Tectonics

• TRANSFORM PLATE BOUNDARIES
• Occur when two plates rub against, or move
  parallel to, each other.
• Results include earthquakes along the San Andreas
  Fault.

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Plate Tectonics

• Distribution of Earths land developed through
  movement of lithospheric plates.

250 million years ago All land is connected t-one super continent (Pangaea)
200 million years ago Pangaea divides into northern Laurasia and southern Gondwanaland
100 million years ago Laurasia and Gondwanaland break apart
50 million years ago continents closely resemble current distribution
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Geologic Processes

• SURFACE-MODIFYING PROCESSES
• leave behind evidence of activity on Earths
  surface.
• are dynamic processes that continually change
  Earth.
• can be slow and steady (e.g., erosion, sediment
  transport).
• can be sudden and disastrous (e.g., earthquake,
  volcanoes).
• human activity can speed up, cause, or otherwise
  affect natural geologic processes
• farming and mining can speed up wind and water
  erosion.
• deforestation can increase the occurrence of
  landslides and mudflows.
• global warming and climate change can both lead
• directly to rising temperatures, melting
  glaciers, and rising sea levels.
• indirectly to floods, earthquakes, hurricanes,
  and increased volcanism.

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SURFACE-MODIFYING PROCESSES

• Tectonism
• fracture and deformation of Earths crust
• Volcanism
• molten rock reaches surface
• basaltic lava flows (fluid eruptions of molten
  rock)
• pyroclastic flows (eruptions of solid debris such
  as rock and ash)
• Water-modifying / fluvial force
• water erosion
• sediment transport
• sandbar formation

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SURFACE-MODIFYING PROCESSES

• Aeolian process
• wind erosion
• rock carving and shaping
• sand dune formation
• sediment transport
• Glacial process
• landscape leveling
• sediment and rock transport
• creation of fjords, crevasses, cliffs, rock
  formations
• Gravitational processes
• landslides, mudflows, avalanches