Chatper 2 Flashcards
What is geologic env.(the earth) made of?
geologic materials
We must study these materials
What materials make up the earth(name them)
Rocks, minerals, soil , etc
Env. Geologists/engineers must answer certian questions about the earth
How earth, minerals, and rocks were formed
Why several geologic events occur today
How were these events in the past
How will they be in the future
IMPORTANT
What do geologists use to answer these questions
How earth, minerals rocks were formed
Why several geologic events occur today
How were these events in the past
How will they be in the future
They use concepts like Uniformitarianism (Uniformity)
What does Uniformitarianism state
States that the present is a key to the past
We must know the present in order to study the past
Allows us to bring the past to the present which helps is interpret the past/predicting potential future events
EXPECT for possible differences in rates chemical and physical process’s in the past
Explain the Orgin of the solar system and the earth(Big Bang)
The earliest most popular belief is earth cam from the BIG BANG
10-15 billion years ago
A big cosmic ball exploded and discharged gas
A billion years later cloud of gas separated into smaller clouds called galaxies
Which also created milky way (our galaxy)
Under gravity, smaller clouds (nebulas) were formed from the galaxies
Look at Picture in Notes
How our solar system was formed(Nebula)
One nebula(smaller cloud) from milky way condensed under gravity
It began contracting and rotating
It flattened into a disc, with the sun in the middle, and the materials formed planets
Sun burnt off excess hydrogen and planets became fully develop
Earth Origin In specific(4.6 billion)
)Name earth layers)
4.6 billions years ago, eddies(materials) swirled around the sun to form the earth
These eddies consisted of silifon, iron, oxgyen and etc
Eddies formed 3 main concentric layers
Core(Inner layer)
Mantle(Middle layer)
Crust(Outer Layer)
Explain the core IMPORTANT
Volume and Denisty?
16% total volume of earth
Density of 10-13 g/cm3
Consists of iron and nickel
Two sublayers in core
-Small solid inner layer
-Large liquid outer layer
Explain the Mantle
Denisty and Volume?
Surronds the core
83% of earth volume
Denisty 3.3-5.7 g/cm3
Has three sub zones
Lower mantle: solid and forms most of earths interior
Asthenosphere: Surrounds lower mantle
You can form manga there if it melts
Upper Mantle:
Solid and surrounds asthenosphere
Crust and Mantle form Lithoshpere
Lithoshpere is broken up into pieces called plates(Plate tectonics)
These plates cause volcanic eruption, mountain ranges, formations of oceans
Explain crust
(Two Types)
Outermost layer of the earth
TWO types
Continental crust
20-90 km thick
Average density 2.7 g/cm3
Contains silicon and aluminum
Oceanic Crust
5-10 km(thin)
Density 3.0 g/cm3
Mainly igneous rocks
Look at notes
What are materials in the earth made up of
(Specfic thing)
Matter
anything with mass and occupies space
(plants, animals, water)
Three types of matter
Solid: Rigid substance, retains shape, rocks, minerals,
Liquid, flow easily, takes shape of container, water, gasoline
Gas: Flow easily expands to fill up container
Water vapor
What is matter made up of
It is made up of chemical elements
and these elemnts consist of smaller particles which are atoms
Explain Atoms
Smallest indivisible unit of matter(Like oxgyen)
Atoms consist of nucleus which have protons and neutrons
The nucleus makes up most of the mass or weight of the atom
Negatively charged particles are called electrons
What is a nucleus composed of
One or more protons and neutrons
Proton
Particle with positive electrical charges
Neutron
Particle with no charge (neutral)
What are electrons
Negatively charged particles that encircle the nucleus(Check notes)
The number of protons in the nucleus of an atom determines what?
Atoms are characterized by atomic mass number or atomic wieght
This is the number of protons and neutrons
Electrons do not contribute to the mass of an atom
Explain Isotopes
Atoms of the same elements may have different numbers if neutrons and therefore different atomic mass number or atomic weight
Example carbon can have a atomic mas of 12, 13 ,14
but the conssnt is that they all have 6 protons but different neutrons
Explain Atomic structure
An atom may loose an electron to become positively charged or may gain an electron to become negatively charged
A negatively or positively charged atom is called an ion
What is an ion
A negatively or positively charged atom is called an
Explian minerals
Natural occurring, inorganic with a definite chemical composition and physical properties
This excludes diamonds ,rubies, plants, organic animals
Most minerals are silicates (consist of silicon and oxygen)
What are the properties of minerals
Chemical composition
Crystal Structure
Physical properties
the most useful properties r
Color, luster, crystal form, cleavage and hardness
(Color doesnt really help)
Igneous Rocks
Formed from magna
Once formed, it moves toward surface, thus losing heat and minerals begin to recrystallize
The rate at which it colls down dtermeines rocks shape and size
Slow colling- Large coarse grains(Granite)
Fast cooling - small grains(Basalt)
(look at note)
Sedimentary rocks
Derived from physical and chemical weathering of pre existing rocks
Broken pieces of rocks or sediments
When those pieces of rocks r cements they made sedimentary rocks
Sediments= clay, sand, gravel
Sedimentary rocks= sandstone
(look at note)
Metamorphic rocks
-formed from pre existing rocks by change in temp.
Pressure and chemical processes
The rock cycle
Inter-relationship between the different rock types
Why do we study rocks
make up the earth
contain mineral resources
Past can be obtained rom knowledge of rocks)
Geologic time/ Gelogic time scale
Time separates geology from other sciences
People think of time in seconds, hours and days
but geologists most recent events are those in the last million years
Geologic time Scale
it is divided into Eon, Era, Periods, Epochs
Froget
Forget
Most minerals are silicates (consist of silicon and oxygen)
Silicates are classfied on what basis
Silicates are classified on the basis on arrangement, packing and sharing of the tetrahedra
Isolated tetrahedra
Continuous or single chain of tet
Continuous sheet
3 dimensional network of tet
(View notes0