WHAT’S IN THE ROCKS!. Bell Ringer 9-22-14 If you were to put the following events in to a time sequence of first to last, how would you do it? What else.

WHAT’S IN THE ROCKS!

Bell Ringer 9-Bell Ringer 9-22-1422-14If you were to put the following events in to If you were to put the following events in to

a time sequence of first to last, how would a time sequence of first to last, how would you do it? What else would you add?you do it? What else would you add?

Go to schoolGo to school

Wake upWake up

Eat lunchEat lunch

Put clothes onPut clothes on

StateState Performance Performance IndicatorsIndicatorsSPI 0807.5.5 SPI 0807.5.5 Compare fossils Compare fossils

found in sedimentary rock to found in sedimentary rock to determine their relative agedetermine their relative age

TOC: TOC: Geologic History Notes Geologic History Notes

ObjectivesObjectivesDescribe the process of relative dating to determine the age of rocks

Apply geologic principles by using fossils to date sedimentary rocksCompare and Contrast different types of fossils in sedimentary rock to determine their relative age

Sedimentary RockSedimentary RockSedimentary rocks cover cover 75% of the Earth’s land of the Earth’s land area.area.

Layer after layer of eroded Layer after layer of eroded earth is earth is deposited on top of on top of each. Theseeach. These layers are are pressed down more and pressed down more and more through time, until more through time, until the bottom layers slowly the bottom layers slowly turn into turn into rock..

PlastiglomeratePlastiglomerateExample of a sedimentary rockExample of a sedimentary rock

Now researchers have discovered an unexpected way that some plastic waste is persisting: as a new type of stone.

Researchers have collected samples of plastiglomerate rock material from the polluted Kamilo Beach in Hawaii

Relative DatingRelative DatingScientists use Scientists use differentdifferent methods methods to determine the to determine the ageage of objects of objects

in sedimentary rocks. in sedimentary rocks. One method, One method, RelativeRelative datindatingg, ,

examines a fossilexamines a fossil’’s s positionposition within rockwithin rock layerslayers to estimate to estimate

its age.its age.

The The bottombottom layers of rock are layers of rock are usually theusually the oldestoldest, and the , and the toptop layers are usually the layers are usually the youngestyoungest..

Scientists can use the Scientists can use the orderorder of of rock layers to determine the rock layers to determine the relativerelative age of objects within the age of objects within the layers.layers.

Discuss with elbow partner Discuss with elbow partner which layer is the oldest in which layer is the oldest in this rock column and which this rock column and which is the youngest.is the youngest.

Identify the type of rock in Identify the type of rock in the oldest and youngest the oldest and youngest layers. layers.

Which is the biggest fossil in Which is the biggest fossil in the rock column? Is the the rock column? Is the fossil young or old relative fossil young or old relative to the other fossils in the to the other fossils in the rock column?rock column?

The Geologic The Geologic ColumnColumnTo make relative dating To make relative dating

easier, easier, geologistsgeologists combine data from all of combine data from all of

the the knownknown rock rock sequences around the sequences around the

world.world.

From this information, From this information, geologists created the geologists created the geologicgeologic columncolumn — an ideal — an ideal sequence of rock layers that sequence of rock layers that contains contains allall of the known of the known fossilsfossils and and rockrock formations on formations on Earth, arranging layers from Earth, arranging layers from oldest to youngest.oldest to youngest.

PalaeontologyPalaeontologyPalaeontologyPalaeontology is the science is the science

involved with the study of past involved with the study of past life. life.

Scientists who study past life are Scientists who study past life are called called palaeontologistspalaeontologists. .

Palaeontologists collect Palaeontologists collect datadata by by studying studying fossilsfossils..

Dinos ‘quickly’ shrunk into birds Paleontologists researched a new analysis of bones, feathers and

teeth from 120 dinosaur species suggest a string of adaptive changes and shrinkages that led to birds!

Bet y

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know

!

A fish out of water! Future Fossil News Alert

Recently, this fish, a Senegal bichirs can walk – and breathe on land!

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Section 2 Section 2 Looking at Looking at

FossilsFossils

The The remainsremains or or physical physical evidenceevidence of an of an organism organism preservedpreserved by by geologic geologic processes is processes is called acalled a FossilFossil..

Fossils in rocks happen when organisms Fossils in rocks happen when organisms die, the fleshy parts decompose and are die, the fleshy parts decompose and are buried quickly in sedimentary rocks.buried quickly in sedimentary rocks.

The hard parts are left to become The hard parts are left to become fossils.fossils.

Fossils in Fossils in Amber occurs when occurs when insects get insects get stuck in stuck in tree sap that that hardens quickly. quickly.

Petrification is the is the process in which process in which minerals minerals replace an organisms an organisms tissues.

One form of One form of petrification is petrification is called called permineralization, , which is the which is the process in which process in which minerals filling filling pore spaces of an pore spaces of an organism’s tissues. organism’s tissues.

Frozen fossils occur when occur when animals are frozen animals are frozen in ice and die. We in ice and die. We find them 1000s of find them 1000s of years later when years later when it thaws.it thaws.

Fossils in Asphalt occurs when occurs when animals are animals are preserved in thick, preserved in thick, sticky pools of sticky pools of asphalt. asphalt.

Trace fossils are any are any naturally preserved naturally preserved evidence of an animal’s evidence of an animal’s activity.

Three types:Three types:

1.Track- - footprintfootprint2.Burrows- shelters made by shelters made by animalsanimals

3.Coprolites- preserved preserved animal dunganimal dung

Discuss with Discuss with your elbow your elbow partner partner discuss discuss analyze why analyze why are tracks are tracks and coprolites and coprolites considered considered trace fossils? trace fossils?

BurrowBurrow

CoprolitCoprolitee

Some fossils do not contain any original Some fossils do not contain any original material of the original organism. material of the original organism. MoldsMolds form when sediments cover the form when sediments cover the organism, such as shell, and the hard organism, such as shell, and the hard part is alter removed by weathering or part is alter removed by weathering or erosion.erosion.

A A castcast is an object that is is an object that is created when created when sedimentsediment fills fills a mold and becomes a mold and becomes rockrock..

History of Changing History of Changing OrganismsOrganisms

Scientists study the Scientists study the relationshipsrelationships between fossils to interpret how between fossils to interpret how

life has life has changedchanged over time. over time.Since the fossil record is Since the fossil record is

incompleteincomplete, palaeontologists , palaeontologists look for look for similaritiessimilarities between between

fossils over time to try to track fossils over time to try to track changechange.

Using Fossils to Date Using Fossils to Date RocksRocks

Scientists have found Scientists have found that that particularparticular types of types of fossils appear only in fossils appear only in certain certain layerslayers of rock. of rock.

By dating rock layers By dating rock layers aboveabove and and belowbelow these fossils, scientists these fossils, scientists can determine the can determine the timetime span in span in which the organism which the organism livedlived..

If the organism lived for a If the organism lived for a relatively relatively shortshort period of time, period of time, its fossils would show up in its fossils would show up in limitedlimited layers. layers.

Index fossils are fossils of are fossils of

organisms that organisms that lived for a lived for a relatively relatively short, well short, well

defined defined geologic geologic

timespan. timespan. TrilobiteTrilobitess

Using Fossils to Interpret Using Fossils to Interpret the Pastthe PastFossils can reveal changes in the Fossils can reveal changes in the

environment.environment.Scientists have found marine fossils Scientists have found marine fossils on mountaintops (e.g. Yoho National on mountaintops (e.g. Yoho National Park) Park)

The presence of these fossils means The presence of these fossils means that rocks were once below the that rocks were once below the surface of an ocean.surface of an ocean.

Middle TN, specifically Murfreesboro, Middle TN, specifically Murfreesboro, was once covered by a shallow sea.was once covered by a shallow sea.

Marine fossils found in the limestone Marine fossils found in the limestone tell scientists that. tell scientists that.

FINDASAURUS ACTIVITY Scenario: A paleontologist from Tennessee went on vacation to Montana where

he discovered dinosaur bones in a particular layer of rock. He wondered if the same layer existed in Tennessee so he could find bones closer to home. If that particular rock appears on Earth’s surface, continuously, all the way from Montana to Tennessee he would be able to walk along the layer to follow it. That would be easy, but unfortunately, the easy way never seems to work. Erosion would make it impossible to follow the layer all the way from Montana to Tennessee. One of the most reliable ways to locate fossils is with other fossils. Index fossils can be used to track a layer from Montana to Tennessee, or from Montana to France. Relative dating places events in sequence within the rock layers while the process of determining if layers in different places are the same is called correlation.  

1.There are two stacks of rock layers, one in Montana and one in France. Your job is to determine: Which layers in Montana correlate with layers in France by matching the letters. Which layer in France contains the same dinosaur fossil as layer “d” in Montana.  

2.Draw the fossils in the layers shown on the chart. For example, index fossil #2 should be drawn only in layers c and i. Make your best effort at reproducing the drawing.  

3.Using colored pencils connect the borders of the rock layers in Montana with those in France.

2-minute journal reflection using accountable talk ( I hypothesize that ...) on which layer is correct and what you learned today.

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