What do index fossils indicate

Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email. Andrew Alden. Geology Expert. Andrew Alden is a geologist based in Oakland, California. He works as a research guide for the U. Geological Survey. Updated August 09, Featured Video. Cite this Article Format. Alden, Andrew.

Geologic Maps of the 50 United States. Learn About the Different Dinosaur Periods. Tectonic Plates' Effect on Evolution. The Permian-Triassic Extinction Event.

Your Privacy Rights. To change or withdraw your consent choices for ThoughtCo. At any time, you can update your settings through the "EU Privacy" link at the bottom of any page. These choices will be signaled globally to our partners and will not affect browsing data. A good index fossil is one with five characteristics: it is distinctive globally widespread abundant limited to a particular geologic time and is robust and preserves well Most fossil-bearing rocks formed in the ocean as being buried in sediment is easiest there.

So the major index fossils are marine organisms global and universal and only a very few terrestrial organisms are index fossils limited to young rocks in specific regions and not universal for example: quickly evolving rodent teeth.

Floating eggs and infant stages riding on ocean currents are helpful in giving index fossil worldwide distribution. Good index fossils need to be both -- abundant and vulnerable Abundant and globally widespread over a relatively short period of time. Vulnerable to environmental change and extinction. Explanation: Index fossils are fossils of organisms that lived during only one short period of time.

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