Term
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Definition
| the science that deals with determining the ages of rocks is called ___. |
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Term
| relative dating and absolute dating |
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Definition
| What are the two methods of dating rocks? |
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Term
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Definition
| this type of rock dating uses fundamental principles of geology to determine which rocks are older and which are younger. |
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Term
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Definition
| this type of rock dating quantifies the date of the rock in years. this is done primarily by radiometric dating (or analysis of the breakdown of radioactive elements in the rocks over time). |
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Term
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Definition
| ___ on the time scale are drawn where important changes occur in the fossil record, such as extinction events. |
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Term
| eons, eras, periods and epochs |
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Definition
| The geologic time scale is divided into a number of types of units of differing size. from the largest units to the smallest units, they are ____. |
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Term
| eons, eras, periods, and epochs |
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Definition
| What are the geochronologic units? |
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Term
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Definition
| ___ are the largest division of geologic time. |
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Term
| archean eon, proterozoic eon, and phanerozioc eon |
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Definition
| In order from oldest to youngest, the three eons are: ___, ___, and ___. |
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Term
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Definition
| The eon which is "ancient or archaic" oldest rocks on earth |
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Term
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Definition
| This Eon is "beginning life" (2.5 billion to 542 million years ago) |
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Term
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Definition
| This eon is "visible life" (542 million years ago to present) |
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Term
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Definition
| The ___ and the ___ are together referred to as the Precambrian, meaning "before the Cambrian Period" |
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Term
| Precambrian; before the Cambrian period |
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Definition
| The Archean and Proterozoic are together referred to as the ___, meaning "___". |
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Term
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Definition
| the Precambrian covers __% of geologic history |
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Term
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Definition
| The ___ covers 87% of geologic history |
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Term
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Definition
| there are ___ eras in the Phanerozoic Eon. |
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Term
| paleozoic era, mesozoic era, and cenozoic era |
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Definition
| the three eras in the phanerozoic eon from oldest to youngest are: ___, ___, and ___. |
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Term
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Definition
| the era in the phanerozoic eon that means "ancient life" (such as trilobites) |
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Term
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Definition
| the era in the phanerozoic eon that means "middle life" (such as dinosaurs) |
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Term
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Definition
| the era in the phanerozoic eon that means "recent life" (such as mammals) |
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Term
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Definition
| eras are divided into ___. |
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Term
| Permian Period, Carboniferous Period (Mississippian and Pennsylvanian Periods in North America), Devonian Period, Silurian Period, Ordovician Period, and the Cambrian Period |
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Definition
| What are the periods in the Paleozoic Era from youngest to oldest? |
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Term
| Permian Period, Carboniferous Period (Mississippian and Pennsylvanian Periods in North America), Devonian Period, Silurian Period, Ordovician Period, and the Cambrian Period |
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Definition
| What are the periods in the Paleozoic Era from youngest to oldest? |
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Term
| cretaceous period, jurassic period, triassic period |
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Definition
| what periods are in the mesozoic era? |
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Term
| neogene period and the paleogene period |
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Definition
| What periods are in the cenozoic era? |
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Term
| quaternary period and tertiary period |
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Definition
| On maps and in publications prior to 2003, you will see the two periods of the Cenozoic Era listed as:___ |
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Term
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Definition
| What is the biblical calculation of the earth? |
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Term
| He was one of the fist people to attempt to calculate the age of the earth, which he said was created on October 23, 4004 B.C. |
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Definition
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Term
| It was based on the calibration of solar and lunar cycles against dates and events recorded in the Old Testament |
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Definition
| How did James Ussher figure out the biblical calculation of the earth? |
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Term
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Definition
| What was the exact age of the earth according to James Ussher? |
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Term
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Definition
| When did geologists show that Archbishop James Ussher's calculation of the earth could not be correct? |
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Term
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Definition
| Elements with various numbers of neutrons (but the same number of protons) are called __ of that element |
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Term
| Elements with various numbers of neutrons but the same number of protons |
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Definition
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Term
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Definition
| What are radioactive isotopes? |
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Term
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Definition
| Unstable isotopes undergo ___, releasing particles and energy |
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Term
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Definition
| Unstable isotopes undergo radioactive decay, releasing ___ and ___. |
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Term
| radioactive (unstable and non-radioactive (stable) |
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Definition
| Some elements have both ___ and ___ isotopes |
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Term
| The radioactive parent element is unstable and undergoes radioactive decay to form a stable daughter element |
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Definition
| What happens when atoms decay? |
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Term
| argon 40; 1.25 billion years |
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Definition
| Potassium 40, a radioactive parent isotope, turns into ___, and has a half life of ___. |
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Term
| strontium 87; 48.8 billion years |
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Definition
| Rubidium 87, a radioactive parent isotope, turns into ___, and has a half life of ___. |
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Term
| lead 208; 14 billion years |
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Definition
| thorium 232, a radioactive parent isotope, turns into ___, and has a half life of ___. |
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Term
| lead 207; 704 million years |
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Definition
| uranium 235, a radioactive parent isotope, turns into ___, and has a half life of ___. |
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Term
| lead 206; 4.47 billion years |
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Definition
| uranium 238, a radioactive parent isotope, turns into ___, and has a half life of ___. |
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Term
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Definition
| carbon 14, a radioactive parent isotope, turns into ___, and has a half life of ___. |
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Term
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Definition
| what is argon 40's parent isotope? |
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Term
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Definition
| what is strontium 87's parent isotope? |
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Term
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Definition
| what is lead 208's parent isotope? |
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Term
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Definition
| what is lead 206's parent isotope? |
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Term
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Definition
| what is nitrogen 14's parent isotope? |
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Term
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Definition
| The decay rates of the various radioactive isotopes are measured directly using a ___. |
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Term
| The mass of a quantity of a radioactive element is measured. then, after a particular period of time, it is analyzed again. the change in the number of atoms over time gives the decay rate. |
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Definition
| How does the mass spectrometer work? |
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Term
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Definition
| many radioactive elements can be used as ___. each radioactive element decays at its own constant rate. |
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Term
| the length of time over which decay has been occurring. |
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Definition
| Once the rate at which an element occurs is measured, geologists can estimate ___. |
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Term
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Definition
| a ___ is the time it takes for half of the parent radioactive element to decay to a daughter product. |
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Term
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Definition
| ___ are the best kinds of rocks for age dating. |
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Term
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Definition
| The dates that igneous rocks give tell when the magma cooled. |
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Term
| the weathering of igneous rocks |
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Definition
| Radioactive mineral grains in sedimentary rocks are derived from ___. |
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Term
| cooling of the magma that formed the igneous rock |
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Definition
| The dates of sedimentary rocks are at the time of the ___. |
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Term
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Definition
| The date of sedimentary rocks do not tell anything about when the sedimentary rock was ___. |
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Term
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Definition
| if the sedimentary rock has a ___ that formed on the seafloor as the rock was cemented, then it may be possible to date it. |
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Term
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Definition
| The greensand mineral, glauconite, contains potassium, and can be dated using the ___ technique. |
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Term
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Definition
| The ___ mineral, glauconite, contains potassium, and can be dated using the potassium-argon technique. |
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Term
| potassium; potassium-argon |
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Definition
| The greensand mineral, glauconite, contains ___, and can be dated using the ___ technique. |
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Term
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Definition
| The greensand mineral, ___, contains potassium, and can be dated using the potassium-argon technique. |
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Term
| relative and absolute dating |
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Definition
| The ages of sedimentary rocks and fossils are determined using both ___ and ___ dating. |
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Term
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Definition
| The ___ was established by combination of absolute and relative dating repeatedly for many locations around the world |
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Term
| absolute and relative dating |
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Definition
| The geologic time scale was established by using a combination of ___ and ___. |
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Term
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Definition
| The oldest rocks that have been dated are ___. |
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Term
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Definition
| Meteorites date from about the origin of the solar system and the earth, about ___ years. |
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Term
| origin of the solar system and the earth |
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Definition
| Meteorites date from the time of the ___, which is about 4.6 billion years old |
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Term
| 3.3 to about 4.6 billion years |
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Definition
| Moon rocks have similar dates to meteorites, which are about ___. |
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Term
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Definition
| The oldest dates of Earth rocks are ___, which was old detrital zircon grains in sandstone in western Austraila |
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Term
| In old detrital zircon grains in sandstone in western Australia |
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Definition
| In what type of rock was the oldest dates of Earth rock found? |
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Term
- The earth is geologically active. The older rocks may have been eroded away.
- Older rocks may have been deeply buried under sedimentary rocks, or beneath thrust sheets.
- Older rocks may have been heated, metamorphosed, or melted, and their dates "reset" to the time of heating, metamorphism, or melting. |
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Definition
| Why are Earth Rocks Younger than Meteorites and Moon Rocks? |
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