UNIT 1 - Geology Flashcards
Memorization
Geo means?
Earth
Logos
Discourse or study
Theory of Uniformitarianism
The present is the key to the past
Formulated by James Hutton
Theory of Uniformitarianism
Main Branches of Geology
Physical, Historical
Deals with materials that make up the Earth, its structure, surface features, and processes that have given the Earth its present structure and appearance
Physical Geology
Deals with history of the earth, its changing face and structure, and changing forms of living things whose remains are found as fossils in rocks
Historical geology
study of the formation and extraction of earth materials that have some economic potential in society
Economic geology
Earth is?
3rd planet in solar system, only planet that can support life, length of year is 365.2422 years, oblate spheroid or geoid and about 4.5-4.6 billion years old
Greatest ocean depth over 11,000
marianas trench
greatest height of land (8,848 m)
mt everest
tallest mountain if measured from the base
mauna kea
how do we determine the age of materials on the planet?
relative dating and absolute dating
based on the natural radioactive decay of elements found on earth, a process whereby atoms of an element lose particles from their nuclei and become atoms of other elements
radiometric dating
number of years it takes for half of the original atoms of a material to decay
half life
what are the principles of relative dating?
Law of superposition
Original horizontality
Crosscutting relationships
Inclusion
Faunal sucession
in a series of undisturbed sedimentary rocks, the topmost layer is always the youngest and the lowermost layer is always the oldest
law of superposition
sediments are deposited in approximately horizontal, flat lying layer. therefore, a dipping or folded rock must have been displaced or deformed after deposition and solidification
principle of horizontality
if an igneous rock cut across layers of sedimentary rock, the secondary rock must have been there first, the igneous rock introduced after
principle of cross cutting relationships
when a fault cuts through another rock, the faults or intrursion is younger that the rocks with it cuts
principle of crosscutting relationships
if an igneous rock contains pieces of other rock types, those pieces must have been picked up as solid chunks by the invading magma and are older than the igneous rock
principle of inclusion
implies that when one finds exactly the same type of fossil preserved in two rocks, there are of the same age even if the rock are different
law of faunal sucession
what are the theories on earth or solar system formation
close encounter hypothesis
cataclysmic event theory
random capture theory
solar nebular theory
also known as collision theory that is proposed by george lucas leclerc buffon
close encounter hypothesis
also known as collision theory
close encounter hypothesis
the gravity of the passing star tears a succession of bolts from the solar surface
close encounter hypothesis
the sun was once component of a binary star (double star) system
A visiting star or some other phenomenon led to the break-up of the suns companion
debris formed from the planets
Cataclysmic event theory
hannes alfven and gustaf arrhenius
suggested a normal sun which instead of breaking up, captured inerterstellar materials from which the planets and other objects in the solar system were formed
random capture theory
postulated that the sun and planets originated from interstellar dusts and gas called “nebulae” condensation of the gas as it rotates led to the formation of the planets and their stabilization
solar nebular theory
major division of the earth
lithosphere, hydrosphere, atmosphere
solid zone of the earth, made up rocks and soil, includes both the crust and the uppermost part of the mantle, thinnest part is found underneath the ocean (~50 km) thicker in continents (100+km)
lithosphere
cover 70% of the earths surface, 97% is comprised of seas and oceans, only 1% are freshwater (rivers and lakes) 2% snow and glaciers
hydrosphere
layer of air covering the earths surface
atmosphere
8 to 14.5 km, air temperature decreases as height increases
troposphere
14.5 to 50 km temperature is fairly constant
stratosphere
85 to600 km, temperature increases with height
thermosphere
50 to 85 km temperature decreases with height
mesosphere
600 to 10,000 km temperature is high, region where earths atmosphere merges with interplanetary gases
Exosphere
Atmospheric zone base on electrical properties
magnetosphere
this zone, the behavior or ions anatomic particles is contolled almost enirely by the earths magnetic field
magnetosphere
thin outermost layer of the earth
crust
20 to 2,900 km thick, quite hot, temperature range from 879 c
mantle
400 km deep with traces of diamond and olivine, partially molten or soft resulting to the slower travel of seismic waves
upper mantle
400 to 2900 km thick dense highly elastic allowing faster movement of seismic waves
lower mantles
central portion of the earth (radius of -3,500 km)
core
transition zone between crust and mantle
moho layer
Type of seismic waves
P waves, S waves, L waves
Shake or secondary
Moves particles in its path at right angles to the direction of advance, can only travel through solid
S waves
push-pull or primary
Moves particles along its path back and forth
Travel at a soeed of 6.11 km the fastest, can travel to any material
P waves
surface (rayleigh waves or love waves)
Moves particles in its path in a motion forward,. up and back down
travel at a speed of 3.5 km sec
can travel along the surface of any material
L waves
vibration of earth produce by the rapid release of energy from rocks
takes the form of waves, radiates in all direction
can be generated by bomb blasts, volcanic eruptions
earthquake
