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| Religious perspectives on age of Earth |
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Definition
Until 1800s, most accepted church concept of Earthbeing a few thousand years old.
Chinese and Hindu believed the age of Earth was beyond comprehension. |
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Definition
"the present is the key to the past"
father of geology
realized that geologic features could be explained through present day processes.
our mountains are not permanent and can be worn down.
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Term
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Definition
gave Hutton's ideas attention in Principles of Geology.
"present is the key to the past" |
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Definition
geologic processes operating at present are the same processes that operated in the past.
relationship to process and rate.
hutton's concept. |
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Definition
physical laws are independent of time and location.
similar to uniformitarianism. |
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absolute age
age given in years or some other unit of time. |
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Definition
| sequence in which events took place, rather than number of years involved. |
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Definition
surfaces separating two different rock types or rocks of different ages.
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| bodies of rock of considerable thickness with recognizable characteristics that make each distinguishable from adjacent rock units. |
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Definition
beds of sediment dposited in water formed as horizontal or nearly horizontal layers.
sedimentary rocks originally formed in horizontal layers. |
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Definition
| younger sed rocks are on top of older sed rocks. |
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Definition
| an original sedimentary layer extends laterally until it tapers at its edges. |
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Term
| cross cutting relationships |
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Definition
| a disrupted pattern is older than the cause of disruption |
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Definition
| fragments included in a host rock are older than the host rock. |
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Definition
a surface that represents a gap in the geologic record, with the rock unit immediately above the contact being much younger than the rock beneath.
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Definition
contact representing missing rock strata separates beds that are parallel to one another.
unconformity between parallel sed layers, can be hard to tell, need fossil record to be sure. |
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Definition
a contact in which younger strata overlie an erosion surface on tilted or folded layered rock.
unconformity between sed rocks with different bedding orientations (usually inclined beds with parallel on top) |
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Definition
a contact in which an erosion surface on plutonic or metamorphic rock has been covered by younger sed or volcanic rock.
unconformity between layers of sed rocks and sitting on top of older igneous or meta rocks. |
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Definition
determining time equivalency of rock units.
principles and use in relative dating. |
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Definition
can trace a particular formation continuously
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Definition
| can be used to correlate formations of similar age. |
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Term
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Definition
fossils change in predictable manner over geologic time.
allowed rock layers in different places to be correlated based on their fossils. |
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Term
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Definition
a fossil from a very short lived geographically widespread species known to exist during a specific period of geologic time.
fossils from short lived wide spread species. |
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Definition
several different fossil species in a rock layer.
groups of fossils that coexisted can be diagnostic of a particular geologic time. |
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Term
| standard geologic time scale |
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Definition
a worldwide relative time scale.
has three eras
which are divided into periods
and subdivided into epochs. |
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Definition
| denotes the vast amount of time that preceded the paleozoic era |
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Term
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Definition
| began with the appearance of complec life. |
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Term
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Definition
followed the paleozoic.
dinosaurs became dominant animals on land |
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Term
| we live in the ____epoch of the ______period of the ______ era. |
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Definition
quaternary
cenozoic
pleistocene |
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Term
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Definition
| contains most recent ice ages, part of the Quaternary period. |
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Term
| isotopic principles and radioactive decay mechanisms |
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Definition
| decay of unstable parent isotope into stable daughter isotope through alpha decay, beta decay, and electron capture |
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Definition
| loss of alpha particle particle consisting of two protons and two neutrons |
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Definition
| loss of an electron from a neutron to produce a proton |
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Definition
| capture of a electron by a proton to produce a neutron. |
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Definition
| determining the age of a rock through its radioactive elements |
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Term
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Definition
| different numbers of neutrons but same number of protons of a given element. |
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Definition
| the spontaneous nuclear change of isotopes with unstable nuclei |
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Term
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Definition
the time it takes for a given amount of a radioactive isotope to be reduced by one half.
the time it take for half of existing parent isotope to decay to daughter product, is constant for a given radioactive isotope |
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Term
| common isotopic dating systems |
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Definition
uranium thorium lead
potassium argon
rubidium strontium
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Term
| the major subdivisions of the precambrain |
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Definition
hadean
archean
proterozoic
each is regarded as an eon. a fourth and youngest eon is the Phanerozoic |
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