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Index fossils are the fossils of short-lived species which, because of their short lives, can be used by scientists to identify the age of the rock strata in which they're found. (For example, if you know a certain species only lived in the Cambrian period, and you find some fossils of this species in some rock, then you know the other fossils you find in that rock must also have come from the Cambrian period.) Some examples of species that left behind index fossils, and their related historical periods, are:
- Billingsella corrugagta - Cambrian period, Palaeozoic era
- Cactocrinus multibrachiatus - Mississippian period, Palaeozoic era
- Scaphites hippocrepia - Cretaceous period, Mesozoic era
- Neptunea tabulata - Quarternary period, Cenozoic era
See the links below for more examples and info.
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∙ 12y ago
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∙ 7y agoIndex fossils are fossils contained within a rock unit that can be used to find the age of a rock. Since the rock must have been deposited within that organisms lifespan in order for it to be in the rock, that rock layer MUST have been deposited at some point while that organism was alive. If we know when an organism lived, we can thus get an approximate age for the rock. Index fossils can also be useful when comparing the ages of rocks that are not directly next to or connected to each other. As long as two rocks contain the same index fossil, they must have been deposited around the same time.
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∙ 8y agoIndex fossils (also known as guide fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages).
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∙ 12y agoalso known as guide fossils, they are fossils that are used to define and identify geologic periods
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∙ 9y agoto place events on the geologic time scale
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∙ 13y agoIndex fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geological periods
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Why did scientists use trilobites as index fossils?
Trilobites were rapidly evolving and widespread organisms, making them ideal index fossils.
What are the three criteria that must be met in order for a fossil to be considered an index fossil?
An index fossil is organisms that is a signature for certain geographical eras. Index fossils are a charting of time that is used to describe other organisms found in that time era. The fossils were found in the stones that are determinations by carbon indexing and therefore are index fossils.
Are trilobites used as index fossils?
because they changed slowly through time(:
Index fossils during triassic period?
Tropites subbullatusMonotis subcircularis
Trilobites are index fossils because they?
because they change slowly through time
Fossil used to compare the relative ages of fossils?
index fossils
What are index fossils and how are they used to determine the absolute age of sedimentary rock?
Index fossils can be used to help determine the relative age of rock layers. Index fossils are from species that only existed for a short time. Index fossils are found in rock layers. Trilobites and Graptolites are index fossils.
What are index fossils and how are they used to determine the absolute age of sedimentary rocks?
Index fossils can be used to help determine the relative age of rock layers. Index fossils are from species that only existed for a short time. Index fossils are found in rock layers. Trilobites and Graptolites are index fossils.
Why are index fossils more useful then other fossils to paleontologist?
It is because the index fossils has better minds than the paleontologist.
What are index fossil and how are they used to determined the absolute age of sedimentary rock?
Index fossils can be used to help determine the relative age of rock layers. Index fossils are from species that only existed for a short time. Index fossils are found in rock layers. Trilobites and Graptolites are index fossils.
Which are the remains of species that existed on Earth for relatively short periods of time were abundant and were wide spread geographically?
They are called index fossils, an aid to relative dating of rock.
What is fossils organisms that lived a short period of time called?
They are called index fossils.
What fossil used to compare the relative ages of fossils?
An index fossil. An index fossil's age is known, allowing scientists to know the relative age of other fossils based on their position relative to the index fossil. (Ex. If a fossil is deeper in the earth, it is older than the index fossil)
What is a an important tool scientists use to study the relative age of rocks?
Index fossils are used, and are of significant importance in finding the relative age of rock.
Why did scientists use trilobites as index fossils?
Trilobites were rapidly evolving and widespread organisms, making them ideal index fossils.
What fossils are useful in determining the relative age of rocks?
Index fossils
What are index fossils useful for?
Because organisms that became index fossils lived only during specific intervals of geologic time, geologists can estimate the ages of rock layers based on the particular index fossils they contain.
