Rock and Rock Cycle

8/6/2019 Rock and Rock Cycle

1/78

ROCK

AND

ROCK CYCLE

Ma. Victoria Delis-Naboya


2/78

Rocks

Rocks are any solid massof mineral or mineral-like

matter occurringnaturally as part of our

planet.


3/78

ROCK is a naturally formedsolid material that isusually made of

minerals


4/78

1.MINERAL COMPOSITION

- composed of mineralswith

a. physical propertiesb. chemical properties

ROCKCHARACTERISTICS


5/78

2. TEXTURE

- is the size and shape of themineral crystals or grains in arock

SIZE SHAPE

a. coarse a. angular

b. Fine b. rounded

c. glassy


6/78

3. STRUCTURE

- is the arrangement of themineral crystals or grains in arock

a. crystalline or granular structure= spread throughout the rock

b. Fragmental

= grains are cemented togetherby another material in thespaces between them


7/78

3. STRUCTURE

- is the arrangement of the

mineral crystals or grains in a rock

a. crystalline or granular structure= spread throughout the rock

a. Fragmental= grains are cemented together by

another material in the spaces

between them


8/78

The Rock Cycle

Types ofRocks

1. Igneous rock is formed by the

crystallization of molten magma

or lava


9/78

Rocks

The Rock Cycle

Types of Rocks

2. Sedimentary rock is formed from the

weathered products of preexisting rocks that

have been transported, deposited, compacted,

and cemented.

3. Metamorphic rock is formed by the alterationof pre-existing rock deep within Earth (but still

in the solid state) by heat, pressure, and/or

chemically active fluids.


10/78

The Rock Cycle

The Rock Cycle

Shows the interrelationships among the three

rock types (igneous, sedimentary, andmetamorphic)

Magma is molten material that forms deep

beneath the Earths surface.

Lava is magma that reaches the surface.Weathering is a process in which rocks are

broken down by water, air, and living things.

Sediment is weathered pieces of Earth

elements.


11/78

The Rock Cycle


12/78

Energy That Drives the Rock Cycle

The Rock Cycle

Processes driven by heat from the Earthsinterior are responsible for forming both

igneous rock and metamorphic rock.

External processes produce sedimentary

rocks.

Weathering and the movement of weathered

materials are external processes powered byenergy from the sun.


13/78

Formation ofIgneous Rocks

Igneous Rocks

1.Intrusive igneous rocks are formedwhen magma hardens beneath Earths

surface.

2. Extrusive igneous rocks are formed

when lava hardens.


14/78

Classification ofIgneous Rocks

Igneous Rocks

1. Texture

Igneous rocks can be classified basedon their composition and texture.

Coarse-grained texture is caused by slow

cooling resulting in larger crystals. Fine-grained texture is caused by rapid

cooling resulting in smaller, interconnected

mineral grains.


15/78

Course-Grained Igneous Texture


16/78

Fine-Grained Igneous Texture


17/78


Igneous Rocks

1. Texture (continued) Glassy texture is caused by very rapid cooling. Porphyritic texture is caused by different rates

of cooling resulting in varied sized minerals.

2. Composition

Granitic composition rocks are made mostly

of light-colored quartz and feldspar.


18/78

Obsidian Exhibits a Glassy Texture.


19/78

Porphyritic Igneous Texture


20/78


Igneous Rocks

2. Composition (continued)

Basaltic composition rocks are made mostly

of dark-colored silicate minerals and

plagioclase feldspar.

Andesitic composition rocks are between

granitic light-color minerals and basalticcomposition dark-colored minerals.

Ultramafic composition rocks are made mostly

from iron and magnesium-rich minerals.


21/78

Basalt


22/78



23/78

Igneous rocks are formed from the

solidification of molten rock material.

There are two basic types: 1) intrusive

igneous rocks such as diorite, gabbro,

granite and pegmatite that solidifybelow Earth's surface; and 2) extrusive

igneous rocks such as andesite, basalt,

obsidian, pumice, rhyolite and scoria

that solidify on or above Earth's

surface.


24/78

ANDESITE Andesite is a fine-

grained, extrusiveigneous rock

composed mainly of

plagioclase with

other minerals such

as hornblende,pyroxene and

biotite.


25/78

BASALT Basalt is a fine-

grained, dark-colored extrusive

igneous rockcomposed mainly

of plagioclase andpyroxene.


26/78

DRIORITEDiorite is a coarse-

grained, intrusive

igneous rock that

contains a mixtureof feldspar,

pyroxene,

hornblende and

sometimes quartz.


27/78

GABBRO Gabbro is a

coarse-grained,dark colored,

intrusive igneous

rock that

contains feldspar,

augite andsometimes

olivine.


28/78

GRANITE Granite is a

coarse-grained,light colored,

intrusive igneous

rock that

contains mainly

quartz andfeldspar

minerals.


29/78

OBSIDIANObsidian is a dark-

colored volcanic

glass that forms

from the very

rapid cooling ofmolten rock

material. It cools so

rapidly that

crystals do not

form.


30/78

PEGMATITE Pegmatite is a light-

colored, extremely coarse-grained intrusive igneous

rock. It forms near the

margins of a magma

chamber during the final

phases of magma chamber

crystallization. It often

contains rare mineralsthat are not found in other

parts of the magma

chamber.


31/78

PERIDOTITEPeridotite is a coarse-

grained intrusiveigneous rock that is

composed almost

entirely of olivine. It

may contain small

amounts ofamphibole, feldspar,

quartz or pyroxene.


32/78

PUMICE Pumice is a light-

colored vesicularigneous rock. It

forms through very

rapid solidification ofa melt. The vesicular

texture is a result of

gas trapped in themelt at the time of

solidification.


33/78

RHYOLITE Rhyolite is a light-

colored, fine-grained, extrusive

igneous rock thattypically contains

quartz and

feldspar minerals.


34/78

SCORIA Scoria is a dark-colored,vesicular, extrusive igneous

rock. The vesicles are aresult of trapped gas within

the melt at the time of

solidification. It often formsas a frothy crust on the top

of a lava flow or as material

ejected from a volcanic vent

and solidifying while

airborne.


35/78

TUFF Welded Tuff is a rockthat is composed of

materials that were

ejected from a volcano,

fell to Earth, and then

lithified into a rock. It is

usually composed mainly

of volcanic ash and

sometimes contains

larger size particles such

as cinders.


36/78

Formation ofSedimentary Rocks

Sedimentary Rocks

Erosion involves the weathering and the

removal of rock.

Deposition occurs when an agent of

erosionwater, wind, ice, or gravityloses

energy and drops sediments.

Weathering, Erosion, and Deposition


37/78

Formation ofSedimentary Rocks

Sedimentary Rocks

Compaction is a process that squeezes, or

compacts, sediments.

Cementation takes place when dissolved

minerals are deposited in the tiny spaces

among the sediments.

Compaction and Cementation


38/78

Classification ofSedimentary Rocks

Sedimentary Rocks

1. Clastic sedimentary rocks are composed

of weathered bits of rocks and minerals.

Classified by particle size

Two Main Groups

- Shale (most abundant)

Common rocks include

- Conglomerate

- Sandstone


39/78

Shale with Plant Fossils


40/78

Conglomerate


41/78

Classification ofSedimentary Rocks

Sedimentary Rocks

Two Main Groups

2. Chemical sedimentary rocks form whendissolved substances precipitate, or

separate, from water.

Common rocks include

- limestonemost abundant chemical rock- microcrystalline quartz known as chert, flint,jasper, or agate

- evaporites such as rock salt or gypsum

- coal


42/78

Fossiliferous Limestone


43/78

Classification of

Sedimentary Rocks


44/78

Features ofSome Sedimentary Rocks

Sedimentary Rocks

Features of sedimentary rocks are cluesto how and where the rocks are formed


45/78

Sedimentary Rocks

Sedimentary rocks form at or near the

Earth's surface.

R

ocks made from particles of erodedsediment are called clastic sedimentary

rocks, rocks made from the remains or

living things are called biogenicsedimentary rocks, and those that form

by minerals precipitating out of solution

are called eva orites.


46/78

LIMESTONE Limestone is

usually made of thetiny calcite

skeletons ofmicroscopic

organisms that once

lived in shallow

seas like today's

Bahamas.


47/78

SANDSTONE Sandstone forms

where sand is laiddown and

buriedbeaches,dunes and

seafloors. Usuallysandstone is

mostly quartz.


48/78

ROCKSALT

Rock salt is anevaporite

composed mostlyof the mineral

halite, source oftable salt, as well

as sylvite.


49/78

SHALE Shale is a

claystone that isfissile, splitting in

layers. Shale isusually soft and

does not crop outunless harder

rock protects it.


50/78

SILTSTONE Siltstone is made

of sediment that is

between sand and

clay in the

Wentworth grade

scale; it's finer

grained thansandstone but

coarser than shale.


51/78

TRAVERTINE Travertine is a

kind of limestonedeposited by

springs. It is anodd geological

resource that can

be harvested and

renewed.


52/78

ROCK GYPSUMRock gypsum is an

evaporite rock that

forms as shallow sea

basins or salt lakesdry up enough for

the mineral gypsum

to come out of

solution.

.


53/78

PEAT Peat is soft, made

of plant remains,but it's hard

enough to beconsidered a

rock. With heat

and long burial,

peat becomes

coal.


54/78

BRECCIA Breccia is a clasticsedimentary rock that

is composed of large

(over two millimeter

diameter) angular

fragments. The spaces

between the large

fragments can be filled

with a matrix of

smaller particles or a

mineral cement which

binds the rock to ether.


55/78

CHERTChert is a microcrystalline or

cryptocrystalline sedimentary

rock material composed ofsilicon dioxide (SiO

2). It

occurs as nodules and

concretionary masses and less

frequently as a layereddeposit. It breaks with a

conchoidal fracture, often

producing very sharp edges.

Early people took advantageof how chert breaks and used

it to fashion cutting tools and

weapons.

C l i i


56/78

COALCoal is an organic

sedimentary rock

that forms mainlyfrom plant debris.

The plant debris

usually accumulates

in a swamp

environment.C

oal iscombustible and is

often mined for use

as a fuel.

C l t i


57/78

CONGLOMERATEConglomerate is a

clastic sedimentary rock

that contains large(greater then two

millimeters in diameter)

rounded particles. Thespace between the

pebbles is generally

filled with smallerparticles and/or a

chemical cement that

binds the rock together.

IRON ORE


58/78

IRON ORE Iron Ore is a chemicalsedimentary rock that

forms when iron and

oxygen (and sometimes

other substances)

combine in solution and

deposit as a sediment.

Hematite (shown

above) is the mostcommon sedimentary

iron ore mineral.


59/78

Formation of Metamorphic Rocks

Metamorphic Rocks

Metamorphism means to change

form.

Conditions for formation are found a fewkilometers below the Earths surface and

extend into the upper mantle.

Most metamorphic changes occur at

elevated temperatures and pressures.


60/78


Metamorphic Rocks

Contact metamorphism occurs when

magma moves into rock.

Changes are driven by a rise in temperature.

Occurs near a body of magma


61/78


Metamorphic Rocks

Regional metamorphism results in

large-scale deformation and high-grade

metamorphism.

Directed pressures and high temperatures

occur during mountain building.

Produces the greatest volume of metamorphic

rock


62/78

Agents of Metamorphism

Metamorphic Rocks

Heat

Pressure

Provides the energy needed to drive chemical

reactions

Causes a more compact rock with greaterdensity

Origin of Pressure in


63/78

Origin ofPressure in

Metamorphism


64/78

Agents of Metamorphism

Metamorphic Rocks

Hot water-based solutions escaping from the

mass of magma

Promote recrystallization by dissolving original

minerals and then depositing new ones

Hydrothermal Solutions


65/78

Classification of Metamorphic Rocks

Metamorphic Rocks

1. Foliated Metamorphic Rock

2. Nonfoliated Metamorphic Rock

Two main categories

Has a banded or layered appearance

Does not have a banded texture

Classification of


66/78

Classification of

Metamorphic Rocks

Gneiss Typically Displays a


67/78

Gneiss Typically Displays a

Banded Appearance

Marble A Nonfoliated


68/78

MarbleA Nonfoliated

Metamorphic Rock

AMPHIBOLITE


69/78

AMPHIBOLITEAmphibolite is a non-

foliated metamorphicrock that forms through

recrystallization under

conditions of highviscosity and directed

pressure. It is composed

primarily of amphiboleand plagioclase, usually

with very little quartz.

GNEISS


70/78

GNEISSGneiss is foliated

metamorphic rock thathas a banded

appearance and is

made up of granularmineral grains. It

typically contains

abundant quartz orfeldspar minerals.

HORNFELS Hornfels is a fine-


71/78

HORNFELS Hornfels is a fine-grained nonfoliated

metamorphic rock withno specific composition.

It is produced by

contact metamorphism.Hornfels is a rock that

was "baked" while

near a heat source suchas a magma chamber,

sill or dike.


72/78

PHYLLITE Phyllite is a foliate


73/78

PHYLLITE Phyllite is a foliatemetamorphic rock that

is made up mainly ofvery fine-grained mica.

The surface of phyllite

is typically lustrous andsometimes wrinkled. It

is intermediate in grade

between slate andschist.

QUARTZITE


74/78

QUARTZITEQuartzite is a non-

foliatedmetamorphic rock

that is produced bythe metamorphism

of sandstone. It is

composed primarilyof quartz.

CHLORITE SCHIST


75/78

CHLORITE SCHIST

Schist is metamorphic

rock with well developedfoliation. It often

contains significant

amounts of mica whichallow the rock to split

into thin pieces. It is a

rock of intermediatemetamorphic grade

between phyllite and

gneiss.

MUSCOVITE SCHIST


76/78

MUSCOVITE SCHIST

Schist is metamorphic

rock with well developedfoliation. It often

contains significant

amounts of mica whichallow the rock to split

into thin pieces. It is a

rock of intermediatemetamorphic grade

between phyllite and

gneiss.

G SC S S hi t i t hi k


77/78

GARNETSCHIST Schist is metamorphic rock

with well developed foliation.

It often contains significantamounts of mica which allow

the rock to split into thin

pieces. It is a rock of

intermediate metamorphic

grade between phyllite and

gneiss. The specimen shown

above is a "garnet schist"because it contains a

significant amount of garnet.

SLATE


78/78

SLATESlate is a foliated

metamorphic rockthat is formed

through themetamorphism of

shale. It is a low

grade metamorphicrock that splits into

Rock and Rock Cycle

Documents

Transcript of Rock and Rock Cycle