FridayNovember 11,

2011

(?? )

The Launch PadFriday, 11/11/11

List the major steps in the development of Earth’s atmosphere and oceans that lead to life on Earth as we

know it today.Earth’s primitive atmosphere was formed by a process called

“outgassing.” Water vapor condensed to form clouds and rainwater that formed

the oceans. Oxygen levels in the atmosphere steadily increased as a result of photosynthetic bacteria in the

ocean.Outgassing produced acidic conditions that caused an accelerated rate of

weathering of Earth’s rocky surface.Products of this weathering were carried to the oceans, thus increasing the salinity

of the oceans..

The Launch PadFriday, 11/11/11

How old is the Universe?

How old is the Earth?

13.6 billion years old

4.5 billion years old

Assignment Currently Open

Summative or Formative

Date Issued

Date Due

Date Into

Grade Speed

Last Day

Project – Moon Features F1 10/18 10/21

Quiz 9 S (last 6-wks) 11/2 11/2 11/3 11/17

Video WS – Fearless Planet – Earth Story F2 11/3 11/10

Activity – Draw Earth’s Internal Structure

F3 11/8 11/9 11/10 10/14

Quiz 10 S1 11/10 11/10 11/11 12/2

AnnouncementsI will be available

today after school until 5:00 PM.

Latest NewsIn 2006, a farmer found a meteorite buried

in a hillside in the Missouri town of Conception Junction (population 202).

Only now has the out-of-this-world value of the space rock discovery come to light.

Geochemist Randy Korotev of Washington University in St. Louis and his colleagues have identified the space rock as a rare

type of pallasite meteorite worth about $3.4 million, the researchers said today. Only

19 other pallasites had ever been found in the United States. The meteorite traveled a long road to find its way into Korotev's hands. Researchers think this meteorite was once part of an asteroid that orbited the sun in the asteroid belt between Mars and Jupiter. At some point, this fragment was knocked into an orbit that crossed

Earth's path, and it was pulled down to our planet by gravity.

The Geologic Time Scale

The Geologic Time ScaleThe geologic time scale divides geologic history into units.Subdivisions of the scale:

• Eon - greatest expanse of time. There are four eons• Phanerozoic (“visible life”) – the most recent eon • Proterozoic • Archean • Hadean – the oldest eon

• Era - Subdivision of an eon. Example: Eras of the Phanerozoic eon • Cenozoic (“recent life”) • Mesozoic (“middle life”)• Paleozoic (“ancient life”)

• Eras are subdivided into periods.• Periods are subdivided into epochs.

The Geologic Time ScaleoEonoEra

oPeriodoEpoch

The Geologic Time Scale

Figure 11.19

The Geologic Time Scale

ActivityMake your own Geologic Time

Scale, labeling all eons, eras, and periods. Include the epochs at

your discretion.

The Launch PadWednesday, 10/20/10

In what eon, era, period, and epoch are we now living?

The Phanerozoic EonThe Cenozoic Era

The Quaternary PeriodThe Holocene Epoch

LabThe Geologic Time Scale

The Launch PadThursday, 10/21/10

What are the names of the eons if we consider there to

have been only two in Earth’s history?If the Earth is 4 500

millions years old, how many years did each

eon occupy?What percentage of Earth’s history did

each occupy?

The Precambrian Eon and the Phanerozoic

EonPrecambrian – 3958

million years, Phanerozoic – 542

million yearsPrecambrian – 88%, Phanerozoic – 12%

LabThe Geologic Time Scale

The Launch PadFriday, 10/22/10

Name an important factor that caused the

Precambrian Eon to change to the

Phanerozoic Eon.

First organisms with shells and other hard

body partsName an important

factor that caused the Paleozoic Era to change

to the Mesozoic Era.

Great Permian extinction

Name an important factor that caused the

Mesozoic Era to change to the Cenozoic Era.

Extinction of dinosaurs and many

other species

The Geologic Time ScaleGeologic time is divided into Eons.

1. Precambrian Eon

a) Archean Eon

b) Proterozoic Eon

2. Phanerozoic Eon

The Geologic Time ScaleEons are further divided into Eras.

1. Archean Eon• Eoarchean Era• Paleoarchean Era• Mesoarchean Era• Neoarchean Era

2. Proterozoic Eon• Paleoproterozoic Era• Mesoproterozoic Era• Neoproterozoic Era

3. Phanerozoic Eon• Paleozoic Era• Mesozoic Era• Cenozoic Era

The Geologic Time ScaleThe Phanerozoic Eon is further divided into Periods.

1. Phanerozoic Eon• Paleozoic Era

• Cambrian Period• Ordovician Period• Silurian Period• Devonian Period• Carboniferous Mississippian Period• Carboniferous Pennsylvanian Period• Permian Period

• Mesozoic Era• Triassic Period• Jurassic Period• Cretaceous Period

• Cenozoic Era• Tertiary Period• Quaternary Period

The Geologic Time ScaleThe Cenozoic Era is further divided into Epochs.

• Cenozoic Era• Tertiary Period

• Paleocene Epoch• Eocene Epoch• Oligocene Epoch• Miocene Epoch• Pliocene Epoch

• Quaternary Period• Pleistocene Epoch• Holocene Epoch

The Precambrian Eon The Precambrian

Eon, which is divided into the Archean and the Proterozoic Eons, spans about 88% of

Earth’s history. Much of Earth’s stable continental crust was created during this time.Partial melting of

the mantle formed volcanic island arcs and ocean

plateaus.

The Precambrian Eon These crustal

fragments collided and accreted to

form larger crustal provinces.

Larger crustal areas were

assembled into larger blocks

called cratons.Cratons form the core of modern

continents.

Formation of Continental Crust

According to one model, the growth of large continental masses were accomplished through the collision and

accretion of various types of terrains, including volcanic arcs and oceanic plateaus.

The Extent of Crustal Materials Remaining From the Archean and Proterozoic Eons

Map showing the major geological provinces of North America and their ages in billions of years

(Ga). It appears that North America was

assembled from crustal blocks that were joined

by processes very similar to modern plate

tectonics. These ancient collisions produced

mountainous belts that include remnant island

arcs trapped by colliding continental fragments.

The Precambrian Eon The

Supercontinents The supercontinents

were large landmasses that consisted of all, or

nearly all, of the existing continents.

Pangaea was the most recent supercontinent, but perhaps an even larger one, Rodinia,

preceded it.Splitting and

reassembling of supercontinents have

generated most of Earth’s major mountain

belts.Supercontinents have

also profoundly affected Earth’s climate over

time.

Possible configuration

of the supercontinent

Rodinia

Figure 12.15

The Precambrian Eon It was during the Precambrian Eon

that life first began on the

Earth.Although the

Precambrian Eon contains some 88%

of Earth's history, its fossil record is poor because organism were soft-bodied during this time, resulting in little

remaining evidence.

The Precambrian Eon The majority of Precambrian fossils are stromatolites that

are often heavily metamorphosed or deeply

buried.However, preserved cells have been discovered at selective sites, such as the 2.0 Ba Gunflint Formation Jasper stromatolites

from Gunflint Formation near Mackies, northern Ontario.

The Precambrian Eon

The first primitive prokaryotic single-celled organisms appeared in the

oceans in the form of bacteria

(eubacteria or Achaea).

The earliest life forms were prokaryotes

that evolved in the seas, possibly as early as 3.8 Ga.

The Precambrian Eon Earth’s first living organisms were probably

chemotrophs existing in an anoxic world and producing H2S or CO2.

The Precambrian Eon Nearly 3.5 Ga, photosynthezing

cyanobacteria began releasing oxygen into the atmosphere as a by-product of the

process of photosynthesis.

The Precambrian Eon The first multi-cellular organisms appeared

toward the end of the Precambrian Eon, sometime prior to 542 Ma.

The Precambrian Eon When the eukaryotes (single-celled

organisms with a nucleus) evolved through endosymbiosis is disputed, with claims as

early as 3.4 Ga, but with less equivocal fossils dating from 1.8 to .8 Ga.

The Precambrian Eon With the eukaryotes comes sexual

reproduction, enabling genetic diversity and the concomitant ability to adapt to and

survive environmental changes.

The Launch PadMonday, 10/25/10

Describe the process by which continents were formed in the

Precambrian Eon.1. Volcanic island arcs and oceanic plateaus rose up in the ancient seas due to the upwelling of

magma from the upper mantle.

3. The crustal provinces then accreted into cratons.4. The cratons then accreted to form the

foundations of the modern continents.

2. The action of plate tectonics caused the arcs to accrete into crustal provinces.

Activity Get your tape from the Lab on the Geologic Time

Scale. On the front side (from Part 1), divide the

Precambrian Eon into Eras. Research what caused the Eras to change and note

this on the tape. On the back side (from Part 2), if you have not done

so already, divide the Phanerozoic Eon into eras, periods, and epochs.

Research what caused the all of the changes and note this on the tape.