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31 Cards in this Set
- Front
- Back
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Archbishop James Usher |
deduced that the age of the earth was 6,000 years based on counting generations in the bible |
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James Hutton |
considered to be the "Father of Geology" and realized that geologic processes take vast amounts of time |
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Uniformitarianism |
processes at work today, like deposition, erosion, and tectonism, were also at work in the past |
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Charles Lyell |
published a series called "Principles of Geology" that explain relative age of dating principles |
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Charles Darwin |
published "On the Origin of Species" describing evolution of species by natural selection |
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Lord Kelvin |
undertook the colossal task of calculating an actual age of the earth using thermodynamics |
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Arthur Holmes |
used radioactive isotopes to determine the actual age of the earth |
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Earth |
4.54 Billions years old |
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Superposition |
In an undisturbed sequence of sedimentary rocks, the oldest is on bottom and the youngest is on top |
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Original Horizontality & Lateral Continuity |
A sedimentary rock layer will remain at a constant thickness and will continue until it tapers out |
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Cross Cutting Relationships |
a rock formation must be older than a fault that cuts through it or an igneous intrusion that invades it |
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Inclusions |
a piece of some pre-existing rock, must be older than its surroundings |
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Igneous Intrusion |
this is only possible due to the fact of younger rocks surrounding sedimentary rocks, magma intruding and then cooling and solidifying |
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Faunal Succession |
a rock's relative age can be determined by the fossil's types it contains |
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Succession of Landscape Development |
Erosional features such as canyons and river channels must be younger than the rock formations they erode
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Conformity |
represents no missing time between formations |
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Unconformity |
represents missing time in "rock record." |
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Disconformity |
a type of unconformity often recognized by "Erosional," and the contact is parallel, but the contact surface shows signs of erosion-often shows that a very minimum amount of time is missing |
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Angular Unconformity |
underlying layers are tilted relative to overlying layers, represents missing time due to tectonics |
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Nonconformity |
contact between eroded igneous or metamorphic layer and overlying sedimentary rocks-usually displays a very large gap of missing time. |
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Absolute Age Dating |
determining an actual age, in years, for geologic events or formations |
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Radiometric Dating |
determining the absolute ages by how much radioactive decay has occurred |
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Atomic Number |
Number of protons defines the element |
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Atomis Mass |
Number of protons + neutrons |
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Alpha Decay |
loss of an "alpha particle," which is equivalent of 2 protons and 2 neutrons -Results in atomic number decreasing by 2 and atomic mass decrease by 4 |
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Beta Decay |
loss of a "beta decay," and is equivalent of the loss of an electron from the nucleus -Results in atomic number increasing by 1 and no change in atomic mass |
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Electron Capture |
Electron obtained by the nucleus, Proton becomes a Neutron -Results in an atomic number decrease by 1 and no change in atomic mass |
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Half Life |
The time it takes for half of the radioactive element in a sample to decay from parent to daughter |
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Hadean Eon |
Earth Forms- it is completely molten and no rocks would survive from this time |
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Archean Eon |
Life (early prokaryotic-single celled), oceans, and continents become part of this eon |
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Proterozoic Eon |
Stromatolites form, oxygen becomes abundant in the atmosphere, Banded Iron formations, Rodinia (first super continent) forms, Snowball Earth forms |
