quiz 1 1) what is the theory of uniformitarianism? 2) this principle states that in an undisturbed...

Quiz 1Quiz 1

1)1) What is the Theory of What is the Theory of Uniformitarianism?Uniformitarianism?

2)2) This principle states that in an This principle states that in an undisturbed sequence of rocks, the undisturbed sequence of rocks, the youngest layer is always on top.youngest layer is always on top.

3)3) Give 1 Steno’s LawGive 1 Steno’s Law

4)4) William Smith contributed what law?William Smith contributed what law?

5)5) How old is the earth?How old is the earth?

ILLUSTRATE THE ILLUSTRATE THE

GEOLOGIC TIME SCALEGEOLOGIC TIME SCALE

NEPTUNISM NEPTUNISM

(Johann Lehmann/Abraham Werner)(Johann Lehmann/Abraham Werner)

Majority of the earth’s rocks had been Majority of the earth’s rocks had been chemically precipitated in a universal chemically precipitated in a universal sea.sea.

PLUTONISM: PLUTONISM:

Successive rocks of the earth were Successive rocks of the earth were formed by igneous fusionformed by igneous fusion

CATASTROPHISM:CATASTROPHISM:

Sudden violent forces or catastrophes Sudden violent forces or catastrophes had shaped the earth’s surface.had shaped the earth’s surface.

UNIFORMITARIANISM (James Hutton)UNIFORMITARIANISM (James Hutton)

‘‘Present is the key to the past.’Present is the key to the past.’

Theory of the Earth (James Hutton, Theory of the Earth (James Hutton, 1788)1788)

Principles of Geology (Charles Lyell, Principles of Geology (Charles Lyell, 1830)1830)

GEOLOGIC MAPS GEOLOGIC MAPS

(William Smith, late 18(William Smith, late 18thth century) century)

““the same strata were found always in the same strata were found always in the same order and contained the the same order and contained the same peculiar fossils”same peculiar fossils”

-PRINCIPLE of FAUNAL and FLORAL -PRINCIPLE of FAUNAL and FLORAL SUCCESSIONSUCCESSION

GEOLOGIC TIMEGEOLOGIC TIME

Relative Time vs Geologic Time ScaleRelative Time vs Geologic Time Scale

STENO’S LAWSSTENO’S LAWS

Principle of…Principle of…► Original Original

HorizontalityHorizontality► SuperpositionSuperposition

► Lateral ContinuityLateral Continuity► Cross Cutting Cross Cutting

RelationshipsRelationships► InclusionsInclusions

Nicholas StenoNicholas Steno

1. Principle of Original 1. Principle of Original HorizontalityHorizontality

A stratigraphic A stratigraphic section of section of Ordovician rock Ordovician rock exposed in exposed in central central Tennessee, USA. Tennessee, USA. The sediments The sediments composing these composing these rocks were rocks were formed in an formed in an ocean and ocean and deposited in deposited in horizontal layers.horizontal layers.

2. Principle of Superposition2. Principle of Superposition

Youngest Strata

Oldest Strata

Stratigraphic Stratigraphic column on north column on north shore of Isfjorden, shore of Isfjorden, Svalbard, Norway. Svalbard, Norway. Since there is no Since there is no overturning, the overturning, the rock at the rock at the bottom is older bottom is older than the rock on than the rock on the top by the the top by the Principle of Principle of Superposition.Superposition.

3. Principle of Lateral 3. Principle of Lateral Continuity Continuity

Lateral ContinuityLateral Continuity

4. Principle of Cross Cutting 4. Principle of Cross Cutting RelationshipsRelationships

5. Principle of Inclusions5. Principle of Inclusions

EARLY ESTIMATES OF THE EARLY ESTIMATES OF THE DURATION OF GEOLOGIC TIMEDURATION OF GEOLOGIC TIME

1)1) Rate of Deposition (5Rate of Deposition (5thth century BC) century BC)

Herodotus: delta must be thousand of Herodotus: delta must be thousand of years old, given the yearly rate of years old, given the yearly rate of deposition of sediment (1 ft of deposition of sediment (1 ft of sediment per 1000 yrs for 450,000 ft sediment per 1000 yrs for 450,000 ft would yield an age of beginning of would yield an age of beginning of Cambrian)Cambrian)

Loophole: Pre-cambrian deposits are not Loophole: Pre-cambrian deposits are not included; thickness of strata is difficult included; thickness of strata is difficult to measure accurately in concorted to measure accurately in concorted and fractured formation.and fractured formation.

2) Salt in Oceans 2) Salt in Oceans

-involved the calculation of total -involved the calculation of total amount of salt in the ocean (16 amount of salt in the ocean (16 quadrillion) tons) compared with the quadrillion) tons) compared with the amount of salt added yearly (160 amount of salt added yearly (160 million tons).million tons).

- 100 million years- 100 million years

Loophole: Calculations ignore the vast Loophole: Calculations ignore the vast quantities of salt present in quantities of salt present in sedimentary sequences in many parts sedimentary sequences in many parts of the world.of the world.

3) Rate of Cooling (Lord Kelvin, 193) Rate of Cooling (Lord Kelvin, 19thth century)century)

-assumed that the earth originated as a -assumed that the earth originated as a molten ball which had been pulled out molten ball which had been pulled out of the sun and that the original of the sun and that the original temperature of the earth was that of a temperature of the earth was that of a melting point of an average igneous melting point of an average igneous rockrock

-70 million years-70 million years

Loophole: it was assumed that no Loophole: it was assumed that no internal source of heat existed within internal source of heat existed within the earth. It was not known by then the earth. It was not known by then that radioactive decay releases a that radioactive decay releases a significant amount of heatsignificant amount of heat

ASSIGNMENT : READ ABOUT ASSIGNMENT : READ ABOUT RADIOACTIVE DATING. Cite and RADIOACTIVE DATING. Cite and explain two examples.explain two examples.

BASIC PALEONTOLOGYBASIC PALEONTOLOGYI.I. Nature of FossilsNature of Fossils

II.II. Moneran and Protistan KingdomsMoneran and Protistan Kingdoms

III.III. Animal and Plant KingdomAnimal and Plant Kingdom

IV.IV. Requisites of FossilizationRequisites of Fossilization

FOSSILS - Latin: fossus, having been dug FOSSILS - Latin: fossus, having been dug up up

- preserved remains or traces of - preserved remains or traces of animals, plants and other organisms from animals, plants and other organisms from the pastthe past

FOSSIL RECORD – totality of fossils and FOSSIL RECORD – totality of fossils and their placements in rock formationstheir placements in rock formations

““must be older than 10,000 years”must be older than 10,000 years”

FOSSIL FOSSIL EXAMPLE:EXAMPLE:

Three small Three small ammonite ammonite fossils, each fossils, each approx. 1.5cm approx. 1.5cm accrossaccross

FOSSIL FOSSIL EXAMPLE:EXAMPLE:

Eocene Eocene fossil fish fossil fish Priscacara Priscacara liopsliops from from Green Green River River Formation Formation of Utahof Utah

FOSSIL FOSSIL EXAMPLE:EXAMPLE:

Petrified Wood. Petrified Wood. The internal The internal structure of the structure of the tree and bark tree and bark are maintained are maintained in the in the permineralizatiopermineralization processn process

►Places of exceptional fossilizationPlaces of exceptional fossilization

Worldwide, some of the best examples Worldwide, some of the best examples of near-perfect fossilization are the of near-perfect fossilization are the Cambrian Maotianshan shales and Cambrian Maotianshan shales and Burgess Shale, the Devonian Hunsrück Burgess Shale, the Devonian Hunsrück Slate, the Jurassic Solnhofen limestone, Slate, the Jurassic Solnhofen limestone, and the Carboniferous Mazon Creek and the Carboniferous Mazon Creek localities.localities.

BURGESS SHALE - one of the world's BURGESS SHALE - one of the world's most celebrated fossil localities, and is most celebrated fossil localities, and is famous for the exceptional famous for the exceptional preservation of the fossils found within preservation of the fossils found within it, in which the soft parts are it, in which the soft parts are preserved. It is 505 million years preserved. It is 505 million years (Middle Cambrian) in age, making it (Middle Cambrian) in age, making it one of the earliest fossil beds to one of the earliest fossil beds to preserve the soft parts of animals. preserve the soft parts of animals.

►BURGESS SHALE - rock unit is a black BURGESS SHALE - rock unit is a black shale, and crops out at a number of shale, and crops out at a number of localities near the town of Field in the localities near the town of Field in the Canadian Rockies in the Yoho National Canadian Rockies in the Yoho National Park of British Columbia, CanadaPark of British Columbia, Canada

FOSSIL FOSSIL EXAMPLE :EXAMPLE :

Marrella, the Marrella, the most most abundant abundant Burgess Burgess Shale Shale organismorganism

Age: Middle Age: Middle CambrianCambrian

OLDEST FOSSILOLDEST FOSSILSTROMATOLITES – Earth’s oldest fossilsSTROMATOLITES – Earth’s oldest fossils

- from Greek στρώμα, - from Greek στρώμα, strōmastrōma, , mattress, bed, stratum, and λιθος, mattress, bed, stratum, and λιθος, lithoslithos, , rock) are layered accretionary structures rock) are layered accretionary structures formed in shallow water by the trapping, formed in shallow water by the trapping, binding and cementation of sedimentary binding and cementation of sedimentary grains by biofilms of microorganisms, grains by biofilms of microorganisms, especially cyanobacteria (commonly known especially cyanobacteria (commonly known as blue-green algae). They include some of as blue-green algae). They include some of the most ancient records of life on Earth.the most ancient records of life on Earth.

OLDEST OLDEST FOSSILSFOSSILS

Lower Lower Proterozoic Proterozoic StromatoliteStromatolites from s from Bolivia, Bolivia, South South AmericaAmerica

OLDEST OLDEST FOSSILSFOSSILS

Pre-Cambrian Pre-Cambrian stromatolites stromatolites (commonly (commonly referred to as referred to as "Mary Ellen "Mary Ellen jasper") on display jasper") on display at the North at the North American Museum American Museum of Ancient Life. The of Ancient Life. The fossil was originally fossil was originally excavated in the excavated in the Iron Range of Iron Range of Minnesota.Minnesota.

TYPES OF PRESERVATIONTYPES OF PRESERVATIONI) I) PERMINERALIZATIONPERMINERALIZATION - - occurs after occurs after

burial, as the empty spaces within an burial, as the empty spaces within an organism (spaces filled with liquid or organism (spaces filled with liquid or gas during life) become filled with gas during life) become filled with mineral-rich groundwater and the mineral-rich groundwater and the minerals precipitate from the minerals precipitate from the groundwater, thus occupying the groundwater, thus occupying the empty spaces. empty spaces.

For permineralization to occur, the organism For permineralization to occur, the organism must become covered by sediment soon must become covered by sediment soon after death or soon after the initial after death or soon after the initial decaying process. The degree to which the decaying process. The degree to which the remains are decayed when covered remains are decayed when covered determines the later details of the fossil. determines the later details of the fossil. Some fossils consist only of skeletal Some fossils consist only of skeletal remains or teeth; other fossils contain remains or teeth; other fossils contain traces of skin, feathers or even soft tissues. traces of skin, feathers or even soft tissues. This is a form of diagenesis.This is a form of diagenesis.

PERMINERALIZATIONPERMINERALIZATION

A A permineralizepermineralized trilobite.d trilobite.

II) CASTS and MOLDS – when original II) CASTS and MOLDS – when original remains of the organism have been remains of the organism have been completely dissolved or otherwise completely dissolved or otherwise destroyed and all that is left is an organism-destroyed and all that is left is an organism-shaped hole in the rock, it is called an shaped hole in the rock, it is called an external moldexternal mold. If this hole is later filled with . If this hole is later filled with other minerals, it is a other minerals, it is a castcast. An . An internal moldinternal mold is formed when sediments or minerals fill is formed when sediments or minerals fill the internal cavity of an organism, such as the internal cavity of an organism, such as the inside of a bivalve or snail.the inside of a bivalve or snail.

CASTS and CASTS and MOLDSMOLDS

External External mold of a mold of a bivalve from bivalve from the Logan the Logan Formation, Formation, Lower Lower CarboniferouCarboniferous, Ohio.s, Ohio.

III) REPLACEMENT and RECRYSTALLIZATIONIII) REPLACEMENT and RECRYSTALLIZATION

occurs when the shell, bone or other tissue is occurs when the shell, bone or other tissue is replaced with another mineral. In some cases replaced with another mineral. In some cases mineral replacement of the original shell occurs mineral replacement of the original shell occurs so gradually and at such fine scales that so gradually and at such fine scales that microstructural features are preserved despite microstructural features are preserved despite the total loss of original material. A shell is said the total loss of original material. A shell is said to be to be recrystallizedrecrystallized when the original skeletal when the original skeletal minerals are still present but in a different minerals are still present but in a different crystal form, as from aragonite to calcite.crystal form, as from aragonite to calcite.

IV) COMPRESSION FOSSILS - such as those IV) COMPRESSION FOSSILS - such as those of fossil ferns, are the result of chemical of fossil ferns, are the result of chemical reduction of the complex organic reduction of the complex organic molecules composing the organism's molecules composing the organism's tissues. In this case the fossil consists of tissues. In this case the fossil consists of original material, albeit in a original material, albeit in a geochemically altered state. Often what geochemically altered state. Often what remains is a carbonaceous film. This remains is a carbonaceous film. This chemical change is an expression of chemical change is an expression of diagenesis.diagenesis.

COMPRESSIONCOMPRESSION

Fossil seed Fossil seed fern leaves fern leaves from the from the Late Late CarboniferouCarboniferous of s of northeastern northeastern Ohio.Ohio.

V) BIOIMMURATION - a skeletal V) BIOIMMURATION - a skeletal organism overgrows or otherwise organism overgrows or otherwise subsumes another organism, subsumes another organism, preserving the latter, or an impression preserving the latter, or an impression of it, within the skeleton.of it, within the skeleton.

Usually it is a sessile skeletal organism, Usually it is a sessile skeletal organism, such as a bryozoan or an oyster, which such as a bryozoan or an oyster, which grows along a substrate, covering grows along a substrate, covering other sessile encrusters.other sessile encrusters.

BIOIMMURATIONBIOIMMURATION

The star-shaped The star-shaped holes (holes (Catellocaula Catellocaula vallatavallata) in this ) in this Upper Ordovician Upper Ordovician bryozoan represent bryozoan represent a soft-bodied a soft-bodied organism preserved organism preserved by bioimmuration by bioimmuration in the bryozoanin the bryozoan skeleton.skeleton.

OTHER TYPES OF FOSSILSOTHER TYPES OF FOSSILS►TRACE FOSSILS - are the remains of TRACE FOSSILS - are the remains of

trackways, burrows, bioerosion, eggs trackways, burrows, bioerosion, eggs and eggshells, nests, droppings and and eggshells, nests, droppings and other types of impressions. Fossilized other types of impressions. Fossilized droppings, called coprolites, can give droppings, called coprolites, can give insight into the feeding behavior of insight into the feeding behavior of animals and can therefore be of great animals and can therefore be of great importance.importance.

TRACE TRACE FOSSILSFOSSILS

ChirotheriuChirotheriumm footprints footprints in a in a Triassic Triassic sandstone.sandstone.

TRACE TRACE FOSSILSFOSSILS

EubrontesEubrontes, a , a dinosaur footprint dinosaur footprint in the Lower in the Lower Jurassic Moenave Jurassic Moenave Formation at the St. Formation at the St. George Dinosaur George Dinosaur Discovery Site at Discovery Site at Johnson Farm, Johnson Farm, southwestern Utah.southwestern Utah.

TRACE TRACE FOSSILSFOSSILS

ClimactichnitesClimactichnites probably probably trackways from a trackways from a slug-like animal, slug-like animal, from the late from the late Cambrian, central Cambrian, central Wisconsin. Wisconsin. Ruler Ruler in background is in background is 45cm long.45cm long.

MICROFOSSILS - applied to fossilized MICROFOSSILS - applied to fossilized plants and animals whose size is just at plants and animals whose size is just at or below the level at which the fossil or below the level at which the fossil can be analyzed by the naked eye. A can be analyzed by the naked eye. A commonly applied cut-off point commonly applied cut-off point between "micro" and "macro" fossils is between "micro" and "macro" fossils is 1 mm, although this is only an 1 mm, although this is only an approximate guide. approximate guide.

Microfossils may either be complete (or Microfossils may either be complete (or near-complete) organisms in themselves near-complete) organisms in themselves (such as the marine plankters foraminifera (such as the marine plankters foraminifera and coccolithophores) or component parts and coccolithophores) or component parts (such as small teeth or spores) of larger (such as small teeth or spores) of larger animals or plants. Microfossils are of critical animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate importance as a reservoir of paleoclimate information, and are also commonly used information, and are also commonly used by biostratigraphers to assist in the by biostratigraphers to assist in the correlation of rock units.correlation of rock units.

MICROFOSSILSMICROFOSSILS

MicrofossilMicrofossils about 1 s about 1 mmmm

FOSSIL RESIN – (colloquially called FOSSIL RESIN – (colloquially called amber) is a natural polymer found in amber) is a natural polymer found in many types of strata throughout the many types of strata throughout the world, even the Arctic. The oldest fossil world, even the Arctic. The oldest fossil resin dates to the Triassic, though resin dates to the Triassic, though most dates to the Tertiary.most dates to the Tertiary.

The excretion of the resin by certain The excretion of the resin by certain plants is thought to be an evolutionary plants is thought to be an evolutionary adaptation for protection from insects adaptation for protection from insects and to seal wounds caused by damage and to seal wounds caused by damage elements. Fossil resin often contains elements. Fossil resin often contains other fossils called inclusions that were other fossils called inclusions that were captured by the sticky resin. captured by the sticky resin.

These include bacteria, fungi, other These include bacteria, fungi, other plants, and animals. Animal inclusions plants, and animals. Animal inclusions are usually small invertebrates, are usually small invertebrates, predominantly arthropods such as predominantly arthropods such as insects and spiders, and only insects and spiders, and only extremely rarely a vertebrate such as extremely rarely a vertebrate such as a small lizard. Preservation of a small lizard. Preservation of inclusions can be exquisite, including inclusions can be exquisite, including small fragments of DNA.small fragments of DNA.

RESIN RESIN FOSSILFOSSIL

A mosquito A mosquito and a fly in and a fly in Baltic Baltic amber that amber that is between is between 40 and 60 40 and 60 million million years oldyears old

CLASSIFICATION of FOSSILSCLASSIFICATION of FOSSILS- according to system used by biologists according to system used by biologists

for living organisms for living organisms

Carlos Linnaeus – formulated the general Carlos Linnaeus – formulated the general principles of biologic classification which principles of biologic classification which includes the ordering and naming of includes the ordering and naming of plant and animal groups.plant and animal groups.

Kingdom - AnimaliaKingdom - Animalia

Phylum - ChordataPhylum - Chordata

Class - MammaliaClass - Mammalia

Order – PrimatesOrder – Primates

Family - HominidaeFamily - Hominidae

Genus - Genus - HomoHomo

Species - Species - sapienssapiens