Fossils

This category is for questions about the bones, fragments, imprints, and other remainders from a different time. The questions and answer you will find here are history set in stone -- our past, immortalized in solid rock. You will also be able to find questions pertaining to the locations of these fossils, how you might identify them, and how they were formed.

11,401 Questions
Geology
Paleontology
Fossils

How do you determine the age of a sedimentary rock or a fossil contained within it?

This an area of common misconception. Most sedimentary rock, and the fossils contained therein cannot be dated directly with radiometric techniques, but can be dated indirectly. Here's the facts:

  • Because most sedimentary rock is composed of particles of pre-existing rock of various types, each particle can be a different age.
  • Carbon-14 or carbon dating techniques can only be used to date organic material which is of a maximum age of 70,000 years; this leaves out the vast majority of fossils found in rock, and only covering roughly .000016 percent of geologic time.
  • The dating of fossils was originally done by their placement in a geologic column of rock strata. Because of the Law of Superposition, the deeper the stratum, the older it is (in an undisturbed body of rock or sediment). Fossils which were evident in a particular stratum, but missing from other strata were noted as "index" fossils. The presence of these fossils indicated the age of the stratum relative to other layers. The layers of stratum were placed in a geologic column, subdivided, and assigned names based on the presence of different types of fossil organisms. The use of fossils in this manner is known as biostratigraphy and is the basis of "relative dating" of rock layers and fossils, a dating technique that was in effect until the advent of radiometric techniques in the twentieth century.
  • Radiometric dating of rock involves the measurement of the amount of decay in radioactive elements which are present in the rock. Radioactive elements decay at unique rates, depending on the isotope. This rate of decay is known as half-lives, it is the time necessary for ½ of the atoms to decay in a particular element. The decay follows a geometric scale, in that in the first half-life of an element, ½ of the atoms decay, yet in the second half-life, ½ of those remaining decay and so forth. By measuring this decay, and knowing the half life of an element, scientists can date a sample. Radiometric dating is particularly useful in dating igneous and metamorphic rock.
  • Because of geologic events such as plate tectonics and volcanism, suitable material for radiometric dating, such as volcanic tuff, solidified lava, and igneous intrusions have been found as layers on, in, and cut through layers of sedimentary rock. Intrusions are always younger than the rock body they penetrate, meaning that the sedimentary rock in which intrusions are found will be older than a radiometrically dated sample of the intrusion. Lava flows and volcanic ash which form layers in rock will be younger than the rock below and older than the rock above. The solidified intrusions and lava flows can be dated with radiometric techniques.
  • The radiometric dating of suitable rocks (i.e. igneous or metamorphic) in proximity to their sedimentary counterparts, therefore allows the sedimentary rock to be dated as well.
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Global Warming
Fossil Fuels
Fossils

How can fossil fuels harm the environment?

  • Burning fossil fuels creates pollution and pollution is bad for the environment.
  • they produce harmful greenhouse gasses
  • Burning fossil fuels releases carbon dioxide emissions that add to the greenhouse effect. This is causing global warming and climate change.
  • Fossil Fuels are fuels formed by natural resources. It harms the environment because every time we use it, carbon dioxide goes into the air.

A:

What is the environmental impact of the extraction, transport and use of fossil fuels?

The major fossil fuels we use are oil, natural gas and coal.

The oil spill now occurring in the Gulf of Mexico is an unintended consequence in the extraction of fossil fuels. Tanker accidents resulting in oil spillage are another way that fossil fuels impact our environment.

These impacts may harm the ecosystem, but the ecosystem may recover from spills. One of the largest oil spills occurred during the Kuwait war (see associated link), but the Persian sea (Arabian sea) has recovered.

The environmental impacts of burning fossil fuels has resulted in acid rain. The combustion process produces sulfur dioxide, nitrogen oxide and carbon dioxide, which combined with water vapor in clouds produces various acids.

The carbon dioxide from the burning of fossil fuels is considered by many scientific organization to add to climate change or global warming. There is considerable information and technical reports available on the internet. The impacts of acid rain and global warming may be much more long lasting as they are difficult to reverse. A number of related links are included.

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Dinosaurs
Fossils

Why were there never dinosaurs found in Louisiana?

The eastern United States is primarily composed of marine deposits from the Paleozoic, meaning that most fossils are of fish, mollusks, and arthropods.

Dinosaurs have only been found in four states east of the Great Plains: Alabama, Maryland, Missouri, and New Jersey.

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Dinosaurs
History of Science
Fossils

Where was the first fossil in Alberta found?

It was found near the Badlands in Drumheller.

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Paleontology
Fossils

How do fossils form in 5 ways?

Freezing,

Amber,

Tar seeps,

Casts and molds

Petrification

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Geology
Fossils

What is trough cross-bedding?

A common variety of cross bedding. Generally at a relatively low angle it resembles scooped grooves. It is formed by sand dune migration (large or small scale)

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Geology
Paleontology
Fossils

Would horseshoe crabs be useful as an index fossil?

No,

Index fossils are used to date certain rock layers where the fossil is found. So it's usefull when you can find a certain index fossil only in a small period of time. So you can get the most precise dating for the rock layer.

Horseshoe crabs are known as a 'living fossil', the first fossils of horse shoe crabs are found 450 millions years ago.

So when you find a fossil of a horse shoe crab in a rock or sediment, you can't say anything about the age of the rock.

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Geology
Paleontology
Fossils

How are fossils formed?

There are multiple methods of fossilization, but fossils generally are formed by rapid burial of organisms or traces of organisms by sediments.

Fossils occur when the organic material is filled with minerals or the cells of an organism is replaced by the minerals in water. Most of the minerals came from rocks and sands.

Here are the conditions for fossilization or permineralization:

1. Mineral-rich water like flood water or ground-erupted water.

2. Lack of oxygen - to prevent decomposition by oxygen.

3. Pressure - particularly in woods so that minerals can seep deep inside.

4. Usually occur within a few years - fossilization must occur quickly before decomposition takes place.

When a Plant or animal dies in a watery environment and is buried in sediment or soft tissues quickly decomposed leaving the hard bone or shells behind.

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Paleontology
Tanzania
Fossils

Where is the tanzanian fossil site?

olduvai gorge

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Fossils
Geology
Paleontology

How reliable is fossil evidence?


The answer depends on how the word 'reliable' is interpreted in the question:


(1) Is the fossil evidence 'reliable' in interpreting the history of life on Earth?


Fossil evidence IS our understanding of the history of life. Fossils on which this understanding is based include skeletons, roots, leaves, bark, chemical signatures, imprints, carbon residues, burrowing and trail marks, petrified wood, footprints, eggs, gastric stones, fecal matter, and many others, found preserved mainly in stone, but sometimes in ice. There are many ways that fossils can be formed. They include freezing, carbonization, petrification, mineral replacement, unaltered preservation,

recrystallization, andauthigenicpreservation.


The fossil record of life recorded in rock is full of periods of intense diversification, appearances of new lifeforms, and extinction events that affected large percentages of the biota on a worldwide scale.


(2) Are the modern methods used to determine the age of the fossil 'reliable'?Radiometric dating of rock involves the measurement of the amount of decay in radioactive elements which are present in the rock. Radioactive elements decay at unique rates, depending on the isotope. This rate of decay is known as half-lives; it is the time necessary for ½ of the atoms to decay in a particular element. The decay follows a geometric scale, in that in the first half-life of an element, ½ of the atoms decay, yet in the second half-life, ½ of those remaining decay and so forth. By measuring this decay, and knowing the half life of an element, scientists can date a sample. Radiometric dating is particularly useful in dating igneous and metamorphic rock, but not so much for sedimentary rocks and fossils.


Because of geologic events such as plate tectonics and volcanism, suitable material for radiometric dating, such as volcanic tuff, solidified lava, and igneous intrusions have been found as layers on, in, and cut through layers of sedimentary rock and fossils. Intrusions are always younger than the rock body they penetrate, meaning that the sedimentary rock in which intrusions are found will be older than a radiometrically dated sample of the intrusion. Lava flows and volcanic ash which form layers in rock will be younger than the rock below and older than the rock above. The solidified intrusions and lava flows can be dated with radiometric techniques.


The radiometric dating of suitable rocks (i.e. igneous or metamorphic) in proximity to their sedimentary counterparts, therefore allows the sedimentary rock to be dated as well. Radiometric dating techniques are constantly being refined and improved with a resulting increase in accuracy and date range.


Scientific inquiry and the scientific method have contributed greatly to our lives in the fields of electronics, physics, engineering, chemistry, manufacturing, and medicine. This same scientific method is being used in genetics and Earth sciences to broaden our knowledge and understanding of Earth's history, including the origin and evolution of life.

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Fossils

Why can fossils be found in ancient river beds?

water saves bones

Because as the river erodes the soil beneath it and on the banks, the fossils that lie buried there are exposed and wash into the river; then the suspended soil settles onto the fossils in the river bed and covers them again.

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Nuclear Energy
Fossil Fuels
Fossils

Why is nuclear energy better than fossil fuels?

It is better for the environment because it does not release polluting gases like fossil fuels do.

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Fossils

What is a fossil flyer?

pterodactyl

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Paleontology
Fossils

Are mold and cast examples of trace fossil?

Yes, they are.

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Fossils

How do fossil records back up evolution?

Fossil records back up evolution by showing the ancestors of extant species. If species didn't evolve, the fossils would be of species currently living, since none of them would have changed.

Extant = Currently living

Extinct = No longer living

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Fossils
Pugs
The Difference Between

What is paperboard used for?

The most extensive use of paperboard is to make shipping containers, cartons, and packaging. U.S. paper-board producers manufacture the vast majority of paper-board consumed in the United States.

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Tiger Woods
Fossils

Is petrified wood tigers eye?

no

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Fossils

What is a fossil?

A fossil is any evidence of ancient life that is preserved in stone or other material. Fossils can include molds, casts, defecation material, stomach stones, bones, footprints, trails and burrows. Fossils can be preserved in sedimentary rock (and rarely metamorphic and igneous rock), tar pits, and amber, and are usually the result of the organism being covered rapidly upon death. Fossils are very important in helping us trace the history of life on Earth and the evolutionary relationships between organisms of the past and present.

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Geology
Fossils
Rocks and Minerals

How do scientists find the absolute date of fossils?

layer in soil and radioactivity measure

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Geology
Paleontology
Fossils

In what type of rock do most fossils appear?

Rarely a fossil may appear in metamorphic or igneous rock, but the vast majority of fossil evidence presents itself in sedimentary rock. Remains or evidences of life are often preserved by being covered in sediments before decaying or being consumed by predators. The sediments may turn to rock through the process of lithification over time, leaving a record of their presence.

Limestone - by far

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Paleontology
Fossils

Where are most the fossil preserved?

In amber

199200201
Paleontology
Fossils

Why ar trilobites considered index fossils?

Because they changed slowly over time :D

199200201
Geology
Fossils

What type of rock are most fossils found?

Fossils will be found almost exclusively in sedimentary rocks. Sedimentary rocks are formed by the compression and cementation of sediments over millions of years. Organisms that die on, in, or near a body of water have a better chance of becoming fossils due to the fact that fossilization requires that the organism be covered relatively quickly in sediments. Once covered in sediments, some of these remains remain intact and can be discovered to have formed fossils or fossilized remains within the layers of the rock. Shale is a particularly good rock for this to occur in, and some limestones like chalk, are composed almost entirely of fossilized marine animal remains.
false!
sedumntary

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Paleontology
Fossils

What type of fossil forms when tree resin becomes hardened?

If you've seen Jurrasic Park, you would know it's amber.

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Pokemon Ruby Sapphire and Emerald
Fossils

How do you find the fossil in the sand once you choose the other one in emerald?

After getting the first fossil talk to the fossil maniac who lives west from fallarbor town after you speak to him go back to the desert you should find Mirage Tower has appeared go in there with the Mach Bike to find the other fossil.

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