Distinctive, widespread, abundant and limited in geologic time.
a fossil found in rocks one time period. Index fossils are commonly found, widely distributed fossils that are limited in time span. They help in dating other fossils found in the same sedimentary layer. For example, if you find a fossil from an unknown era near a fossil from a known time, you can assume that the two species were from about the same time. fossils are preserved animals or plants. but index fossils are fossils have wide distribution,many of them,evolves rapidly, and very easy to recognize. Ammonites are index fossils. The fossils were made only in a certain short time period. 1. index fossil-a fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found. guide fossil. fossil-the remains (or an impression) of a plant or animal that existed in a past geological age and that has been excavated from the soil. 1  Facebook. index fossil-a fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found. guide fossil. fossil-the remains (or an impression) of a plant or animal that existed in a past geological age and that has been excavated from the soil. Definition: While every fossil tells us something about the age of the rock it's found in, index fossils are the ones that tell us the most. Index fossils (also called key fossils or type fossils) are those that are used to define periods of geologic time. A good index fossil is one with four characteristics: it is distinctive, widespread, abundant and limited in index fossil-a fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found. guide fossil. fossil-the remains (or an impression) of a plant or animal that existed in a past geological age and that has been excavated from the soil. 1  Facebook.
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what makes a fossil an index fossil