Module 3 - science

Define a Mineral

naturally occurring inorganic solid with a specific chemical composition and crystalline structure.

What does inorganic mean

Not alive and never were alive

Define Magma

Molten material that forms & accumulates below Earth’s surface

What determines what minerals will form

the type & number of elements in the magma

What determines the size of the minerals crystals

The rate at which the magma cools

How do minerals crystallize

Supersaturated & Evaporites

How do geologists identify minerals (pt 1. )

Color

Specific gravity

texture

Density

Special Properties

How do geologists identify minerals (pt. 2 )

Luster

hardness

cleavage & fracture

streak

crystal form

Define luster

Teh way that a Mineral reflects light from its surface

What is the difference between nonmetallic and metallic luster

Metallic is shiny and it reflects light, Nonmetallic is not shiny and is describer as dull/pearly

Define Hardness

a measure of how easily a Mineral can be scratched

How does Moh’s Hardness scale work

Through a scratch test that compares the relative scratch resistance of minerals

Describe the difference between cleavage and fracture

Cleavage is a Mineral that splits easily

Fracture is minerals that break rough and jagged

Define streak

The color of a Mineral when it is broken up and powdered

What is the streak test

You rub the mineral on an unglazed porcelain plate

Define texture

How a Mineral feels

Define Density

The atomic mass & structure of a Mineral

What is Density’s formula

D = m/v

What is the most common measure of density used by geologists

Specific Gravity

Define the mineral group, silicates

A Mineral that contains silicon & oxygen, & usually one or more other element

Silicates make up what percentage of minerals on earth

96%

Describe and define the basic building block of silicates

Tetahedron - 3D shape that resembles a pyramid

Define Mineral group carbonates

minerals composed on one or more metallic elements and CO 3²

Define the mineral group oxides

compounds of oxygen and a metal

define the mineral group sulfates

composed of element and the sulfate ion

Define the mineral group halides

made up of chloride or fluoride along with calcium, sodium, and potassium

define the mineral group native elements

Such as , silver, or copper, is made of one element

why are minerals important to society

Used to make many things such as computers, cars, television, etc.

Define an Ore

Useful substance that can be mined at a profit

Describe how and ore is not a permanent categorization

it can change if the supply of/demand for that mineral changes

Define gems

valuable minerals that are prized for their rarity & beauty

How do igneous rocks form

lave/magma cools & minerals crystallize

what affects the type of igneous rock that forms

composition of the magma

what affects magma’s melting temp. and viscosity

silica content

what are 2 ways that magma can be formed

1. melting of Earth’s crust

2. melting within the mantle

what are the 4 factors involved in the formation of magma

temperature, pressure, water content, and mineral content

define the geothermal gradient

when temp. increases with depth in the earth’s crust

what is pressure’s effect on a rock’s melting point

the increased pressure on a rock also increases the rocks melting point

what is water’s effect on a rock’s melting point

as water increases, melting point decreases

which minerals melt at higher temp. in the rock

rocks that are rich in iron & magnesium

which minerals melt at lower temp in the rock

rocks that contains higher levels of silicon

define and describe partial melting

the process where some minerals melt at relatively low temp., while other minerals remain solid - as each group of minerals melts, different elements are added to the magma mixture, changing the composition

Bowen’s reaction series demonstrates the relationship between two things

cooling magma & the formation of minerals that make up igneous rocks

define and describe fractional crystallization

when magma cools, the first minerals that crystallize are the last minerals that melted during partial melting

which minerals crystallize first

the last minerals that melted during partial melting

how do intrusive rocks form

magma cools & crystallizes below the surface

what is intrusive rock’s crystal size

easy to see without magnification

How do extrusive rock form

magma cools & crystallizes on the surface

What is extrusive rock’s crystal size

difficult to see without magnification

how are igneous rocks classified

by their mineral compositions

define and describe basaltic/magic rocks

dark colored, contain mostly plagioclase and pyroxene, and have low silica content

Define and describe granitic/felsic rocks

Light colored, contain mostly quartz and feldspar, and have high silica content

Define and describe intermediate rock

rocks that have a composition of minerals that is somewhere between basaltic and granitic

describe how volcanic glass forms

when lave cools so quickly that’s crystals do not form (obsidian)

describe the difference between porphyritic and vesicular texture

vesicular is when it looks spongy & has little holes, porphyritic is when it had small crystals surrounding it

Define weathering

when rocks are exposed and are physically + chemically being broken into smaller pieces

Define sediments

small pieces of rock that move by water, wind, glaciers, and gravity

define sedimentary rock

when sediments become glued together

what does the formation of sedimentary rock begin with

weathering & erosion producing sediments

describe the difference between chemical and physical weathering

chemically - they dissolve

Physical - remain chemically unchanged rock fragments break off

define erosion

the removal and transport of sediment

what are the four main agents of erosion

wind, moving water, gravity, and glaciers

how are eroded materials almost always carried

downhill

define deposition and when it occurs

occurs when transported sediment are deposited on ground or sink to the bottom of a body of water, forming layers with the largest grains of sediment at the bottom and small at the top

define and describe the processes of lithification

the physical and chemical processes that transform sediments into sedimentary rocks

define and describe what lithification begins with

compaction - the weight of overlying sediments forces the sediment grain closer together, causing physical change

define and describe cementation

occurs when dissolved minerals precipitate out of groundwater and their growth glues sediment grains together into solid rock

what is the primary feature of sedimentary rocks

horizontal layering, bedding

define graded bedding

bedding in which the particular sizes become progressively finner & lighter toward the top layers

define cross - bedding

formed as layers of sediment are deposited at an incline across a horizontal surface

how do ripple marks form

when sediments is moved into small ridges by wind/wave action by a river current

what is the difference in how symmetric and asymmetrical ripple marks form

symmetric - back & forth

Asymmetric - flows in one direction

how do you know how far a piece of sediment has traveled

angular & rounded shape

what is the best known feature of sedimentary rocks

fossils

what is the most common type of sedimentary rock

clastic sedimentary rock

how do clastic sedimentary rocks form

from the abundant deposits of loose sediments that accumulate on Earth’s surface

coarse grained

gravel - size

medium grained

sand - sized

fine grained

silt and clay - sized

how do metamorphic rocks form

when high temp. & pressure combine and change the texture, mineral composition of a rock without melting

define metamorphism

the minerals in a rock undergo solid-state alterations, which means that they change into new minerals that are stable under the new temp. & pressure conditions

describe foliated texture

high pressure during metamorphism causes minerals with flat or needle-like crystals to form perpendicular to the pressure, creating the layers observed in foliated metamorphic rocks

describe no-foliated texture

metamorphic rocks composed mainly of minerals that form with blocky crystal shapes

what is low grade metamorphism

low temp. and pressure

what is high grade metamorphism

high temp. and pressure

describe regional metamorphism

when high temp. and pressure affect large regions of earth’s crust, ranging from low - high grade

describe contact metamorphism

when molten material, such as that in an igneous intrusive comes in contact with solid rock

describe hydrothermal metamorphism

when very hot water reacts with rock & alters its chemical & mineral composition

what is the rock cycle

the continuous changing & remaking of rocks

how can igneous rocks form (rock cycle)

when magma cools & crystallizes

how can sedimentary rocks form (rock cycle)

when sediments undergo compaction & cementation

how can metamorphic rocks form (rock cycle)

when sedimentary & igneous rocks go through heat and pressure

how can magma form (rock cycle)

from metamorphic, igneous, & sedimentary rocks melting

how can sediments form (rock cycle)

from igneous, sedimentary, and metamorphic rocks that have been weathered and eroded