CO6 GEO

father of geology

bald

the present is the key to the past

This principle developed in the early 1800’s

led Earth scientist to realize the Earth was very old – at least

millions of years old

more modern term of uniformitarianism

actual age given in years or other unit of time

the sequence in which events took place

surfaces separating successive rock layers (beds)

bodies of rock of considerable thickness with

recognizable characteristics allowing them to be

distinguished from adjacent rock layers

order of events or objects, from oldest to youngest

beds of sediment deposited in water are initially formed as

horizontal or nearly horizontal layers

within an undisturbed sequence of sedimentary or volcanic rocks, layers get younger from bottom to top

original horizontal layer extends laterally until it tapers or

thins at its edges

a disrupted pattern is older than the cause of the disruption

• Intrusions and faults are younger than the rocks they cut through

contacts between igneous intrusions and surrounding rocks, where surrounding rocks have experienced contact metamorphism

fragments embessed in host rock are older than the host rock (»????)_

surface (contact) that represents a gap in the geological record

the unconformity contact separates beds that are parallel

the unconformity contact seperates a younger layer above from a lower layer that is tilted

an unconformity

in which an erosional surface on

plutonic or metamorphic rock has

been covered by younger

sedimentary or volcanic rock

The determination of

the time – equivalency of rock units

physically

tracing a continuous exposure of a

rock

puts absolute values

(for example, millions of years) on the

ages of rocks and geologic time periods

varieties of the same element

that have different numbers of neutrons

in the nucleus

the spontaneous

nuclear change of isotopes with

unstable nuclei.

• Alpha emission, Beta emission and

Electron capture

time it takes for a given

amount of radioactive isotope to be

reduced by half.

represents 87 % of geologic time and is divided into

three Eons (Hadean, Archean, Proterozoic)

most recent eon that includes all geologic time with

abundant fossil record

• composed of

  • Paleozoic

  • Mesozoic

  • • Cenozoic

“Earth created in 4004 B.C. based on the Bible”

Today numerical dating gives age for Earth of _____

• Earth and the rest of the solar system was very likely formed at this time

are more favorable for fossil preservation than are continental environment, because the rate of sediment deposition tends to be higher

aka guide fossils or indicator fossils

• basis for defining boundaries in the geological time scale and the time correlation of strata

It provides a method for measuring geologic time

directly in terms of a specific number of years

may be emitted from

the nucleus. ___________ consists of

two protons and two neutrons. After

emission, the mass number of isotope is

reduced by four and the atomic number is

decreased by two.

When _______ or electron is

given off from a nucleus, the mass

number remains unchanged because

electrons have practically no mass. The

atomic number increases by one because

the nucleus contains one more proton

than before

geological time scale from longest to shortest

• Hadean

• Archean

• Proterozoic

_ 87% of earth’s history

• named after hades

  • • The Earth undergone differentiation

    • The Moon formed (perhaps based on the Impact Theory)

    • The surface was an ocean of magma until 4.4 Ga based on zircon

    • Outgassing occurred forming the first ocean

“Beginning”

- Starts at around 3.85 Ga where there is a substantial

amount of crustal rocks.

The advent of the _____ marked the time when the

crust was locally cool and stable for rocks to survive

• plate tectonics occured at this time

by the end of this eon, 80% of the earth’s continental land had formed

developed at around 3.2 Ga due to

cyanobacteria secreting a mucus-like substance to

which sediment settling from water sinks.

an exobiologist,

achieved the laboratory

synthesis of amino acids.

• He simulated the early

atmosphere in a laboratory

flask and then sent sparks of

electricity into the mixture.

• The liquid yielded amino acids

and other complex

compounds.

• Spans from 2.5 Ga to 542 Ma

• Encompasses almost half of the Earth’s history

• The surface environment changed from fast-moving

plates, small continents, and an oxygen-poor

atmosphere to an environment similar to today’s world

• The continents formed by at slower rates

• The interior of continents started to cool and strengthen

thus becoming relatively stable

first supercontinent on Earth, formed during 1 Ga

Rodinia’s formation triggered a mountain building

event known as the _____

Rodinia broke away and formed a short-lived supercontinent called ______

At the beginning, life on earth was ______

Alternating

layers of quartz

and iron rich

layers

Near the end of the Proterozoic, 90% of entire Earth was

covered in ice in an event known as the _________ OR SNOWBALL EARTH

occurred 40 million years after the Cambrian Explosion

• New species, genus, family, and order different

taxonomic levels diversified.

• The first crinoids and first vertebrate animals (the

jawless fish) appeared during this time.

the west of the US collided with an island arc

thus causing the ________—

Early land plants appeared during this time.

• The first jawed fish evolved known as the Acanthodians

• Age of the Fish

• First Amphibians

• First Insects

• Mass extinction near the end of this period

First appearance of gymnosperms

• Proliferation of coal-forming swamps

• Diversification of amphibians

• Appearance of reptiles

The largest mass extinction in the Earth’s history.

• happened in permian period

• 95% of marine species died

• One hypothesis is due to massive volcanism in now

Siberia where volcanic flood basalts formed known as

“Siberian Traps”

• PANGEA WAS FORMED

• Bird-hipped dinosaurs

• BIRDS DID NOT EVOLVE FROM THEM

• Lizard-hipped

dinosaurs

A remarkable diversification of life occurred during this

time.

• The reason for the abrupt diversification of life during

this time is unknown for certain.

• However, it is known that the evolution of hard parts

such as shells occurred this time as well the rise of new

phyla

Due to a brief glaciation and associated sea-level

lowering, a mass extinction occurred at the end of the

Ordovician period.

appearance of the first mammals

• during this period, ammonites began to be very abundant

• aka the age of the ammonites

• appearance of the first feathered birds

• start of the great diversification of dinosaurs

peak of the dinosaur evolution

boundary between crataceous and paleogene (pg)

dinosaurs vanished along with 90% of plankton species and up to 75% of plant species

The cause is likely due to the aftermath of a meteorite

impact as evidenced by high concentrations of Iridium

(normally found in meteorites)

A 16-km-deep meteorite crater is found in Mexico

known as _______

Subdivided into several epochs

Three periods

• Paleogene

• Neogene

• Quaternary

The appearance of Earth gradually

produced what we could see

today

• Formation of the largest orogenic

  belt due to the closure of the

  Tethys Sea forming the AlpineHimalayan Chain.

• The predominance of mammals wherein they would

  dominate.

  Dominance of angiosperms

  First appearance of:

  • Horses (Eocene Epoch)

  • Primates and Monkeys (Eocene Epoch)

  • Whales (Eocene Epoch

• 1/3 of the Earth’s

surface was covered in

ice

• Sculpted many

glaciated terranes

• Cause could have

been due cycles in the

Earth’s movements

• changes in the earth’s precession, orbital eccentricity, and axial tilt

• Way the Earth’s axis

of rotation wobbles

The orbital path

describes what the atmosphere is doing over

short timescales

– the average weather pattern in a region over long

periods of time

climate change related to

human activities

also called the

ionosphere

percentage of radiation reflected from the surface

the intensity and wavelength of emitted

electromagnetic radiation depends on temperature

include water vapor, carbon dioxide, methane,

nitrous oxide, and other

Changes in Earth’s orbital patterns

determine input and distribution of solar radiation over long

time scales

the tilt of Earth’s axis varies on a ______ year

timescale

are dark areas on the Sun’s surface that are hotter than

average

Approximately __% of the Sun’s

radiation is reflected back into

space

conversion

of high albedo snow and ice to

lower albedo surfaces

Snow and Ice have high

albedo (true/false)

Darker surfaces have lower

albedos (true/false)

each

greenhouse gas survives in the

atmosphere for different amounts of

time

a relative

measure of each gases ability to trap

heat in the atmosphere

small particles suspended in the

atmosphere.

releases particles and gases into the

atmosphere

alters surface albedo and ocean

circulation over million-year timescales

the study of ancient climates

measuring

temperatures deep in the ground

to infer what temperatures must

have been in the past.

• Large-scale intentional efforts to modify Earth’s climate