SIO 10 midterm studying Flashcards
Geologists see
How rocks transformed.
Layers were once horizontal re now tilted.
Erosion has created high cliffs.
Part of the history of the Earth.
Geology
Is the study of this part of the Earth. Also called Geosciences or Earth Sciences.
Geologists
Someone who studies the Earth exploring diverse regions
Geology sub-disciplines
Environmental Geology Geochemistry Geophysics Sedimentary Structural Geology Tectonics Volcanology
Major Divisions
Eons and Eras
Eons
Phanerozoic
Proterozoic
Archean
Hadean
Eras
Cenozoic, Mesozoic, Paleozoic, PreCambrian
Scientific Method
Series steps for analyzing scientific problems
Scientific Method steps
Recognize have problem or sparse data that appear to correlate.
Collect More Data
Propose Hypothesis
Test hypothesis
Theory
Scientific idea supported by an abundance of facts especially from diverse fields.
Have a physical model for the facts.
Earth
Is unique. Temperature, composition, atmosphere favor life. Dynamic and ever changing. Long and complex history. Dynamic and ever changing. Long and complex history.
Conscious thought
Leads to curiosity and insight, developed across thousands of generation.
Cosmology
Study and structure of evolution of the Universe. Very complicated science.
Renaissance
Rebirth of rational thinking
Foucault’s Pendulum
Proved that the Earth rotates
Earth’s Circumference
˜40,000 km
Eratosthenes Calculations
The sun went directly down a deep well at Syene (at the beginning of summer)
Measures the angle of the shadow at the Alexandria Tower.
The Doppler Effect
Waves compress or relax with relative motion (sound and light).
Moving towards, sound wave compressed gives higher frequency.
Moving away, waves expand gives lower frequency.
Visible wavelengths
400 (blue) 700 (red) nanometers.
Moving star displays Doppler shifted light
Stars moving towards Earth are shifted blue, and vice versa (red)
Hubble
In 1929 recognized this as a Doppler Shift. Concluded Galaxies were moving away rapidly.
Led to Big Bang Theory.
Big Bang
It exploded 13.7 Ga Been expanding ever since.
Light Elements
He, Li, Be, B
Gravity resulted in
Increases in temperature, density and rate of rotation
Nebulae
Formed flattened discs. Heat and mass from collapse ignited nuclear fusion.
Stardust
Stars are true element factories
Heavier Elements
C-Fe #6-#26
Planet
large solid body orbiting a star, nearly spherical, no objects around it.
Small, dense, rocky
Mercury, Venus, Earth and Mars
Terrestrial Planets
Jovian Planets (Jupiter like)
large, low density, gas-giant *jupiter, saturn, uranus, neptune
Solar system formation
The ball at the center grows dense and hot
Fusion reaction begins; the Sun is born
Dust in rings condenses into particles.
Particles coalesce to form planetesimals
Atmosphere and Oceans
The atmosphere develops from volcanic gases. Enough moisture condenses, oceans are formed.
A slice through the Earth
A thin atmosphere, a thin crust of low density rocks, a core of very dense iron alloy.
Kuiper Belt
Diffuse band of icy objects at 35-55 Au. Neptune defines the inner band.
Asteroid Belt
lies between Jupiter and Mars
Magnetic field
Field like giant dipole bar magnet. Extend into space, weaken with distance, forms magnetosphere.
Deflects deadly cosmic radiation
Magnetic Field of Van Allen
Aurora Australis
Southern lights
Atmosphere
Mostly N2 and O2
Atmosphere layers
Troposphere, stratosphere, mesosphere, thermosphere
Earth layers
Atmosphere, hydrosphere, cryosphere, biosphere, lithosphere
Earth’s elemental composition
Fe (32) O (30) Si (15) Mg (14) Others (9)
inorganic earth materials
minerals, comprise rocks and hence most of earth, most rocks are silicates
igneous
cooled from a liquid
Sedimentary
Debris cemented pre-existing rock
Metamorphic
Rock altered by pressure and temperature
Organic earth materials
contain carbon
Volatiles
material that become gas at the surface
Earth’s layers
The crust, the mantle, the core (outer and inner)
With depth
temperature and velocity increase
Layers are made of
crust, upper, transitional and lower mantle, liquid outer and solid inner core.
Crust
Outermost skin of the planet
Continental Crust
Felsic, average thickness 35-40, 2.7 density
Oceanic Crust
Mafic, more dense
Mantle
Solid rock, 82% of Earth’s volume
Upper, Transitional and lower.
Core
Outer- Liquid, Inner-Solid
Lithosphere
Makes up plates, the outermost, made up of both crust and mantle.
Asthenosphere
Mantle below lithosphere
Wegeners theory
Land masses move slowly, once a major continent called Pangea.
Continental drift
Oceans and continents move, split apart and recombine. Sea floor spreading proves this.
Against Continental drift
Viscosity too high, continents and oceans were fixed.
Matching geological Units
Mountain belts across the Atlantic, Appalachians, Caledonides.
The Magnetic field
Can have normal or reverse polarity, inclination.
Paleomagnetism
declination and inclination in rocks often varies from that expected at present position.
Polar Wandering
Layered basalts record magnetic charges over time. Inclination and declination indicate changes in position
Ocean Floor
Mid-ocean ridges
Trenches
Fracture zones
Ocean Crust
Covered by sediments, high heat flow
Marine Magnetic Anomalies
Anomalies created by positive and negative alienation in seafloor basalts. Proves that sea floor spreading does occur
Plate Tectonics
Moving plates change the face of Earth. Fragments of lithosphere.
˜20 tectonic plates
Wegener
Evidence supporting drift
Holmes
Arguing for convection in the mantle
Hess/Dietz
Sea-floor spreading hypothesis.
Archimedes
The principle of buoyancy
Plate boundaries
Location on Earth where tectonic plates meet.
Continental Margin
Where lands meets ocean
Divergent
Tectonic plates move apart. Ex: The Red Sea.
Convergent
Tectonic plates move together
Transform
tectonic plates slide sideways
Formation of Oceanic Crust
Sea floor spreading opens the axial rift valley. Rising asthenosphere melts, forms mafic magma.
Pooled magma solidifies to oceanic crustal rock.
Pillow Basalt
Magma quenched at the sea floor
Dikes
Preserved magma conduits
Gabbro
Deeper magma, same composition as basalt.
MORs
Mid-Ocean Ridges
Ridges
Hot asthenosphere lies at base of MOR/
Hoy asthenosphere moves up at ridge axis.
Subduction
One plate dives into mantle. Recycles oceanic lithosphere, Earth maintains a constant circumference
Subduction features
Accretionary prism, volcanic arc, back arc basin, oceanic trenches
Accretionary Prism
Deformed sediment wedges
Volcanic Arc
A chain of volcanoes on the overriding plate
Back-arc Basin
A marginal sea behind an arc
Triple junctions
Places where 3 plate boundaries coincide
Transform Boundaries
Plates slide past, not created or destroyed. Ex: The San Andreas Fault
Hot Spots
Volcanoes create seamounts
Continental Rifting
Rifting of plates. Places where continent is being stretched.
Plate Collision
Subduction consumes ocean basins
Driving mechanisms
Ridge push, slab pull and mantle convection
Volcano
A vent where molten rock comes out of earth
Igneous rock
Formed by cooling from melt
Magma
Melted rock below the ground
Lava
Melted rock above the ground
Major types of rocks
Felsic, Intermediate, Mafic and Ultramafic
Extrusive
cooling outside of surface
Introsive
Cool at depth
