WednesdayNovember 14,

2012(Introduction to the Geologic Time Scale;

Begin Lab – The Geologic Time

Scale)

The Launch PadWednesday, 11/14/12

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..

Announcements

Assignment Currently Open

Summative or

Formative?Date Issued Date Due Date Into

GradeSpeed Final Day

Quiz 10 S5 11/2 11/2 11/16Video Activity –

Fearless Planet – Earth Story

F1 11/6 11/9 11/16

Quiz 11 S1 11/9 11/9 11/30WS – Origin of the Atmosphere and

OceansF2 11/13 11/16 11/16

Recent Events in ScienceHappy Little Crater on Mercury

www.nasa.gov/multimedia/imagegallery/image_feature_2392.html

Read All About It!

It looks like this little crater on Mercury is happy!

The central peaks of this complex crater have formed

in such a way that it resembles a smiling face.

This image taken by the MESSENGER spacecraft is oriented so north is toward

the bottom.

The Geologic Time Scale

The Geologic Time ScaleThe Geologic Time Scale is a system of

chronological measurement that relates stratigraphy to time.

Stratigraphy is a branch of geology which studies rock layers and layering

(stratification.)

It is primarily used in the study of sedimentary and layered volcanic

rocks.

Stratigraphy includes two related subfields: lithologic stratigraphy or lithostratigraphy, and biologic

stratigraphy or biostratigraphy, and is used by geologists, paleontologists, and

other earth scientists to describe the timing and relationships between events

that have occurred throughout Earth's history.

The Geologic Time ScaleThis scale divides geologic history into units, with the

following subdivisions:Eons are the greatest expanse of time. There are three (or four) eons:

Hadean - the first eonPrecambrian - further subdivided into the Achaean and Proterozoic

eonsPhanerozoic - the most recent and current eon

Eras are subdivisions of an eon. For example, the eras of the Phanerozoic eon are:

the Cenozoic (“recent life”) the Mesozoic (“middle life”)the Paleozoic (“ancient life”)

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

The Geologic Time ScaleEon

ErasPeriodsEpochs

The Geologic Time Scale

Figure 11.19

The Geologic Time Scale

Begin Lab- The Geologic Time Scale