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American Museum of Natural History
Course: American Museum of Natural History > Unit 1
Lesson 4: Dinosaur fossils- Fossil preparation
- What Is a fossil?
- How do we know where to look for dinosaur fossils?
- How do we know where to look for dinosaur fossils?
- How are dinosaur fossils discovered and collected?
- How are dinosaur fossils discovered and collected?
- How are dinosaur fossils prepared in the laboratory?
- How are dinosaur fossils prepared in the laboratory?
- Preparing dinosaur fossils
- Inside the Collections: Paleontology and the Big Bone Room
- Can we clone extinct dinosaurs from DNA preserved in their fossils?
- Can we clone dinosaurs from DNA?
- Barnum Brown: The man who discovered Tyrannosaurus rex
- Quiz: Dinosaur Fossils
- Exploration Questions: Dinosaur Fossils
- Answers to Exploration Questions: Dinosaur Fossils
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How do we know where to look for dinosaur fossils?
Dinosaur fossils are found almost exclusively in sedimentary rocks, which form when sand, silt, mud, and organic material settle out of water or air to form layers that are then compacted into rock. Paleontologists look for fossils in sedimentary rocks that were deposited on the continents, primarily by rivers and streams, or in lakes into which the streams emptied. Occasionally, dinosaur fossils are also found in sedimentary rocks representing ancient, desert sand dunes. The sedimentary rocks must have been formed or deposited during the Mesozoic Era, the geologic time period when nonavian dinosaurs lived. Created by American Museum of Natural History.
Want to join the conversation?
- Have many fossils been found underwater or in oceans?(2 votes)
- There is the unusual case of the North Sea, up by the UK. Much of it was dry land during the last ice age, and it's shallow enough that dredging can bring up fossils. It's nowhere near old enough to have any dinosaurs, though.(1 vote)
- I don't understand this how do they find them? even underwater? omg idk!(1 vote)
- why would foot prints be fossils if there just footsteps(1 vote)
- because footsteps give the scientist info if this creature traveled in herds or going solo(1 vote)
Video transcript
The search for dinosaur fossils, as is
the search for any kind of fossils, is partly based on knowledge, partly based on good strategy, and partly based
on luck. You can't just dig anywhere on the surface of the earth and find them.
Basically, dinosaurs lived during the Mesozoic era, and so you have to find rocks that are exposed on the surface of
the earth that are of that age, and then you can
plan your expedition to go to these localities and look for the particular
kinds of dinosaurs that lived during a particular period of time that your studying. Secondly, you have to have rocks of a particular type, when I say particular type, they are
usually sedimentary rocks rocks that are deposited by the action of streams
or lakes or wind so that they're laid down, and bury these animals. We have found dinosaurs in some very unlikely places, but in general the best dinosaur fossils,
and the most abundant fossils, have been found in particular kinds of terrain, mainly deserts. Deserts, that have a lot of cliffs, a lot of hills,
a lot of relief, why? Because there's a simple mathematical
fact that relates to prospecting. The more surface area you have to look for
something, the better your chances are to find a fossil. So walking along a cannon or a cliff face lets you look at more rock per unit area that's why the great, the famous, dinosaur
fossil territories are places like the Rocky Mountains and the
basins of western North America, the Gobi Desert, and other deserts in
central Asia, and South America the deserts in
Argentina, especially Patagonia, these are great fossil, dinosaur fossil, hunting territory.