GEO: PETROLOGY

Petrology

Petrology

is the study of the origin and composition of rocks, with particular emphasis on the physical, chemical, and possibly biological processes that are involved in the formation of rocks.

is the study of rocks - igneous, metamorphic, and sedimentary - and the processes that form and transform them.

Petrology is the ?

Latin word "ignis" FIRE

"Igneous" comes from the __________ which means ____.

"Magmatic Rocks"

Igneous can also be called as?

cooling and solidification

Igneous Rocks are rocks formed through the __________ of molten rock material called magma.

underneath the crust

Magma develops _______; however, Igneous rocks can still be formed from volcanoes or from the surface of the Earth.

naturally solid.

The mantle and crust of the Earth are ___

True

Magma arises when pressure and temperature conditions force a solid rock to melt. True or False?

three main geological settings: midocean ridges, subduction zones, and hotspots.

Arising magma predominantly occurs in 3 main geological settings which are?

less dense cooling, solidification, and crystallization.

Magma is _____ than the surrounding rocks which causes it to rise to the surfaces and undergoes a change in temperature and pressure resulting to a ____________

Extrusive Igneous Rocks Intrusive Igneous Rocks

2 Groups of Igneous Rocks

Extrusive Igneous Rocks

Magma that comes out as lava and cools on the surface

Intrusive Igneous Rocks

Magma cools off beneath the surface

Extrusive Igneous Rocks

Also called as "Volcanic Rocks"

near the surface of the Earth

Extrusive Igneous Rocks are rocks which are formed ?

mineral crystals fine-grained (aphanatic).

Extrusive Igneous Rock: Lava cools down quickly causing the _________ to have a lesser time to grow which makes the formation of rocks _________

microscopic

Extrusive Igneous Rock: The crystals that formed the rocks are _______ and invisible to the naked eye.

basalt.

Most common type of volcanic rocks is

Basalt Obsidian Andesite Dacite Scoria Pumice

Examples of Extrusive Igneous Rocks

Plutonic Rocks

Intrusive Igneous Rocks are also called as?

Intrusive Igneous Rocks

Rocks which are formed within the Earth's crust

course grained rocks (phaneritic).

Intrusive Igneous Rocks: Slowly cooling of magma causes the crystals to grow without reaching the surface resulting to a _________

Intrusive Igneous Rocks

These rocks are visible with an unaided eye.

texture and composition.

Igneous Rocks are classifies according to its ________

➢ Phaneritic ➢ Aphanitic ➢ Porphyritic ➢ Vesicular ➢ Glassy ➢ Pyroclastic

Diff types of texture of igneous rocks

➢ Felsic ➢ Mafic ➢ Ultramafic ➢ Intermediate

Diff types of composition of igneous rocks

composition.

The chemical and mineral make-up of a rock is referred to as its

Felsic, Intermediate, Mafic and Ultramafic.

The composition of igneous rock is classified into four groups:

silica, iron, and magnesium contained in the minerals

These classifications of the composition of igneous rocks are based on the quantities of?

Felsic

Composition: 65-75% silica Poor in Iron and Magnesium

Intermediate

Composition: 55-60% silica Composition between felsic and mafic

Mafic

Composition: 45-50% silica Rich in Iron and Magnesium

Ultramafic

Composition: less than 40% silica have more Iron and Magnesium, less silica

igneous rock

Granite is an ______, which means it forms when the magma of a volcano oxidizes and then slowly solidifies underneath the earth.

Granite

are easily identified as light-colored and coarse-grained as a result of slow cooling under the surface, enabling for bigger crystal formation.

quartz and feldspar

Granite is mainly composed of ________ and ___________ with minor amounts of mica, amphiboles and other minerals.

Countertops Mount Rushmore Tiles Building Stone

Uses of Granite

"Syrene" which means Aswan.

Syenite originally came from the ancient name ____________

Syenite

It is a coarse-grained rock consisting ferromagnesian mineral and alkali feldspar.

Syenetic rocks

are generally found in association with other plutonic rocks.

SYENITE

They produce relatively modest intrusive bodies or are components of bigger intrusions.

The amount of quartz present in both rocks

SYENITE is considered similar to granite, what are their difference?

• Alkali Feldspar • Quartz • Plagioclase feldspar • Feldspathoids

Compositions of Syenitic Rocks

• Nepheline Syenite • Quartz Syenite • Hornblende Syenite

Types of Syenitic Rocks

Nepheline Syenite

is a white to light grey medium-grained igneous rock.

energy consumption

Nepheline Syenite promotes more rapid melting at lower temperatures, thus reducing __________, lengthening the life of the furnace and improving the yield and quality of glass.

Quartz Syenite

is a syenite rock consisting 5-20% of quartz

Hornblende SyeniteFgabbro

has a wide variety of rocks containing calcium and monoclinic

calcium and monoclinic

Hornblende Syenite has a wide variety of rocks containing

Arkansas and Montana in regions in North America

Syenite Rocks are mostly found in:

❑Construction of Roads ❑Flooring ❑Landscaping ❑Monuments, Artefacts ❑Small Figurines

Syenite Rocks can be used in:

DIORITE This allows for more ion transport, leading to much larger crystals. It is produced in volcanic arcs, and in mountain building where it can occur in large volumes as batholiths in the roots of mountains.

is phaneritic, or coarse grained, and forms at depth when andesitic magma has lots of time to crystallize.

ion transport volcanic arcs, batholiths

The process of diorite formation allows for more __, leading to much larger crystals. It is produced in _ and in mountain building where it can occur in large volumes as in the roots of mountains.

buildings and Statues.

One important use of Diorite is as stone that is used for ____________

Diorite

• statue of gudea

• Neolithic ax

• was used extensively by ancient civilizations for vases and other decorative artwork and is still used for art today

GABBRO

intrusive igneous rock that forms from the result of slow cooling of magma inside of a volcano.

basalt, mafic magmas that contain dark colored minerals such as pyroxene, plagioclase, amphibole and olivine.

Gabbro is very similar to the fast cooling, extrusive as they both are formed from

Gabbro

• no quartz

• 45-52% silica content

• A silica-poor intrusive igneous (plutonic) rock chemically equivalent to basalt

❑Consists mainly of calcium rich plagioclase feldspar, clinopyroxene and minor amount of olivine.

Pegmatite

_____ is an igneous rock that form end of the stage a magma's crystallization.

exceptionally large crystals, ave 5cm size, phaneritic

Pegmatites contain___________ and they contain rarely minerals than other types of rocks.

BASALT

is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase and pyroxene minerals.

Tholeiitic basalt - rich in silica and poor in sodium. High and Low Titanium Basalts - classified after titanium content Mid-Ocean ridge Basalt (MORB) High-alumina basalt Alkali basalt Boninite

Types of Basalt

Mid-Ocean ridge Basalt (MORB)

is a tholeiitic basalt commonly erupted only at ocean ridges and is characteristically low in incompatible elements.

High-alumina basalt

BASALT: may be silica-undersaturated or oversaturated

Alkali basalt

BASALT: is relatively poor in silica and rich in sodium

Boninite

is a high magnesium form of basalt that is erupted generally in back-arc basins, distinguished by its low titanium content and trace-element composition.

aggregate dimension stone

USES OF BASALT

DOLERITE

• composed of plagioclase feldspar and pyroxene

is a dark colored igneous rock. It is compositionally equivalent to gabbro and basalt but texturally between them.

Sedimentary Rocks

formed from deposits that accumulates on the surface of the Earth or under the ocean.

pre-existing rocks

Sedimentary Rocks are formed from?

Sediments organic matter.

are composed of minerals or once living matter called ?

Weathering Transport/Transportation Deposition Preservation Lithification

Formation of Sedimentary Rocks

Weathering

the breaking down, disintegration and changing of rocks as a result of their exposure to the environment.

Transport/Transportation

the products are transported away as the weathering process progresses.

Transportation

Sediments move away from its source due to water, wind or ice

Particle Rounding

Abrasion during transportation causes?

reduces

With increased transport distance, the size of the sediment _________

Deposition

sediments of a certain size enter an environment with insufficient energy to convey them, they are deposited.

Deposition

Transported particles settle Accumulation of chemical or organic sediments, typically in water

The location in which deposition takes place beach desert dunes deep sea floor river channel bottom of lake

Environment of deposition

Preservation

sediments are buried successively with other sediments to create sedimentary rocks.

Lithification

process of cementing these rock pieces together.

Lithification involves compaction and cementation of sediments

process in which loose sediments turn into sedimentary rocks

1. Clastic Sedimentary Rock

2. Chemical Sedimentary Rock

3. Organic Sedimentary Rock

Type of Sedimentary Rock (Classification)

detrital sedimentary rocks.

Clastic Sedimentary Rock are also called ?

Clastic Sedimentary Rock

-Formed from cemented sediment grains which come from broken fragments of pre-existing rocks.

Conglomerate Sandstone Shale

Examples of Clastic Sedimentary Rocks

CONGLOMERATE

❑Formed from large sediments ❑Composed of pebbles and boulders, and smaller particles of calcite or quartz cement that binds the rock together.

SANDSTONE

• ❑Medium-grained clastic sedimentary rock

❑Most common type of sedimentary rock on Earth ❑Made of compacted sand grains

SHALE

❑Fine-grained clastic sedimentary rock.

flakes clay minerals and silt size particles of other minerals.

Shale is composed of mud which is a mix of ___________

❑Has fissile property (split into thin layers).

What property does the sedimentary rock shale have?

Chemical Sedimentary Rock

• precipitation! not made from pre-existing rocks

-Formed by precipitation of minerals from water.

True

Chemical Sedimentary Rock Not made from pieces of pre-existing rocks True or False?

1. Evaporitic Rock

2. Carbonate Rocks

CLASSIFICATION OF CHEMICAL SEDIMENTARY ROCKS

Evaporitic Rock

• ex. rock gypsum and rock salt

Are formed within the depositional basin from chemical substances dissolved in the seawater or lake water.

Carbonate Rock -ex. limestone

Contain Carbonate (CO3) as part of their composition.

50% calcite

Limestone must contain at least _________ to be considered a chemical sedimentary rock

Organic Sedimentary Rock

-Formed from the accumulation of plant and animal debris.

Fossiliferous Limestone Chalk Limestone Coal Limestone

Examples of Organic Sedimentary Rocks