FridayFebruary 17, 2012

(Quiz 20)

Launch PadFriday, 2-17-12

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Quiz 18 S5 2/3 2/3 2/3 2/17

WS – Igneous Rocks (Part 1) F 2/9 2/13

Quiz 19 S6 2/10 2/10 2/10 2/24

WS – Sedimentary Rocks (Part 1)

F 2/15 2/17

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Quiz 20

The Carbon Cycle and Sedimentary Rocks

The Carbon Cycle and Sedimentary Rocks

Stages in the Formation of

Coal

Lithification of SedimentSedimentary rocks are produced through

the processes of lithification. Lithification occurs when loose sediments

are transformed into solid sedimentary rock.

Common lithification processes include:compaction

cementation by calcite, silica, or iron oxide

Features of Sedimentary RocksAt the Earth’s surface, layer upon layer of sediment

accumulates.Each layer records the nature of the environment at

the time that layer was deposited.These layers, called sedimentary strata, or beds, are the most characteristic feature of sedimentary rocks.Separating the strata are bedding planes, flat surfaces

along which rocks tend to separate or break.Each bedding plane marks the end of one episode and

the beginning of another.

Fossils in Sedimentary RocksFossils are the traces or remains of

prehistoric life, and are perhaps the most important inclusions found in some

sedimentary rocks.Fossils help to determine past

environments, are used as time indicators, and are useful for matching rocks from

different places.

WorksheetSedimentary Rocks

(Part 2)

The Launch PadThursday, 1/27/11

Define the terms “sedimentary strata” and “bedding plane.”

Each layer records the nature of the environment at the time that layer was deposited. These layers, called sedimentary strata, or beds.

Separating the strata are bedding planes, flat surfaces along which rocks tend to separate or

break. Each bedding plane marks the end of one episode and the beginning of another.

LabSedimentary Rocks

The Launch PadFriday, 1/28/11

Name the following sedimentary rocks.Conglomerate

BrecciaSandstoneShale

CoquinaCoal

Metamorphic Rocks Metamorphic rocks are those that have changed their form

due to external environmental issues.Metamorphic rocks are produced from preexisting igneous,

sedimentary, or even other metamorphic rocks. Metamorphism takes place where preexisting rock is subjected to temperatures and pressures unlike those in which it formed.

There are different degrees of metamorphism which can be seen in the rock’s texture and in its mineralogy.

An example of low-grade metamorphism is shale becoming slate.

In high-grade metamorphism, obliteration of the rock’s original features occurs.

Metamorphic Rocks Most metamorphism occurs in one of two settings:

When rock is intruded by a magma body, contact, or thermal metamorphism may take place.

Here, change is driven by a rise in temperature within the host rock surrounding a molten igneous body.

During mountain-building, great quantities of rock are subjected to directed pressures and high

temperatures associated with large-scale deformation called regional metamorphism.

What Drives Metamorphism?

The driving agents of metamorphism include heat, pressure (stress) from burial (confining pressure) or from differential stress during mountain

building, and chemically active fluids (mainly water and other volatiles.)

Pressure as a Metamorphic Agent

Metamorphic TexturesThe degree of metamorphism is reflected in the

rock’s texture and mineralogy.When rocks are subjected to low-grade

metamorphism, they become more compact and more dense (like slate.)

Under more extreme conditions, stress caused certain minerals to re-crystallize. Consequently,

many metamorphic rocks consist of visible crystals, much like coarse-grained igneous

rocks.

Metamorphic TexturesThe crystals of some

minerals will recrystallize with a

preferred orientation, essentially

perpendicular to the direction of the

compression force.

The resulting mineral alignment usually gives

the rock a layered or banded appearance

termed foliated texture

Metamorphic TexturesSome metamorphic rocks have a

nonfoliated texture.

Metamorphic rocks composed of only one mineral that forms

equidimensional crystals are, as a rule, not visibly foliated (examples:

limestone and marble.)

Common Metamorphic Rocks

Classification of Metamorphic Rocks

Worksheet

Metamorphic Rocks

The Launch PadMonday, 1/31/11

Name the following metamorphic rocks.slate

marble

schist

anthracite

phyllite

gneiss

quartzite

foliated

nonfoliated

LabMetamorphic Rocks

Classification of Metamorphic Rocks