ch 9-12

molten material works its way to the crust and it might not reach the surface befor it hardens.

magma that reaches the ground surface

mobility of the lava is influenced by high temp (more fluid) lower temp mobility of lava decreases

more viscous ( less fluid)

the gases (volatiles) which provide the forces that erupt molten rock from vent

very fluid and allows expanding gases to bubble upwards and excape from vent. Produces lava fountains

lava moves up but gases are restricted. It increases in size till they explode

flow in thin sheets or ribbons

contain disolved gases held within molten rock.

70% water vapor, 15% carbon dioxide 5% nitrogen 5% sulfur

form at the surface and are are considered extrusive

green, pyro, fire clastss broken fragments

begin with a crack onto the surface of the earth as magma moves strongly towards it

path or corridor that the magma travels through before it erupts on the surface opening called the vent

deep walled depression situated at the summit of calcanoes

large more or less circular depression

• Broad gently sloping volcanoes made of solidified lava flows.
• have grown up from deep ocean floors to form islands.
• ex hawaiian island

• made of pyroclastic fragments ejected froma central vent .Slopes steeper but not as large than shield valcanoes
• Found in flanks and calderas of hawaiian shield valcanoes

• made of alternating layer of pyroclastic materals and lava flows.
• Slopes intermedient between shield and cinder
• ex andes mountains

• supernatural belief
• growth of an island
• geothermal energy
• effects on climate
• volvanic catastrophies

• In Iceland, Loki of Norse mythology is thought to have been imprisoned underground and blows
• lavas and steams through fissures.
• Native Americans of the Pacific Northwest
• regarded volcanoes as warrior gods, who would throw red hot boulders.

Volcanoes are at times, thought to be associated with destruction, but some effects can be beneficial. Hawaii would not have existed without volcanic activity.

underground heat generated can be helpful if harnessed to power turbines for electricity

valcanoes spewing large amounts of gas and material in atmosphere, reduses solar radiationa and drop in temperature offsetting global warming

Pompeii, Italy; Krakatoa, Western Pacific; Mt. Etna, Italy; Mt. St. Helens, U.S. of A.; Fujiama, Japan.

Structures that form from the positioning of the igneous material at depth. They can only be studied after uplifting and erosion

Tabular features that are produced when the magma is injected into fractures.

Tabular features when magma is injected along sedimentary bedding surfaces.

similar to sills but the magma is less fluid

Largest of intrusive igneous body, when magma was formed at depth and then exposed by upliftment and/or erosion

Heat increases with depth. Change in temperature with depth is know as the geothermal gradient.

increases with depth as well and is an important factor in melting the rock.

• gases (volatiles) cause the rock to melt at a lower
• temperature, similar to salt for melting ice. Their effect is magnified by increased pressure as earlier discussed

• Minerals have different melting points as we studied from Bowen’s Reaction Series. As the temperature increases, the minerals with lower melting temperatures in the rock start melting and after they have melted they start rising towards the surface.
• Slowly the composition of the magma approaches the composition of the rock from which it was formed and often the melting is not complete. This is known as partial melting

refers to all changes in the original size and or shape of the rock

rocks return to their original shape and size after the releaase of pressure

rocks do not return to their original shape and size after the release of pressure

at the surface the temperature and pressure is low

materials once the forces exceed their strength. This type of deformation

where the temperature and pressure is high at dephts, involve changing the size and shape of the rocks without fracturing

The mineral composition of the rock establishes its strength. Rocks, like basalt, granite, and quartzite that are composed of minerals break by brittle fracture, as opposed to sedimentary rocks which have zones of weakness break by ductile fracture.

rocks are like a book shelf they will break and deform

are formed as a result of volcanic rocks that are bent into series of wavelike undulations

three dimensional plane which divides the limbs of the folds into more or less two equal halfs

• anticline
• Syncline
• normal faults
• reverse faults
• slip strike fault

when the limbs of the fold dip away from the axial plane, the fold is an

when the limbs of the fold dip towards the axial plane, the fold is a

a rough circular upfoleded structure similar to an anticline

a roughly circular downfolded structure

are fractures in which movement has taken place

vertical movements between the fault plane has taken place

is where the hanging side of the fault move down is relation to the footwall side of the fault

is where the hanging wall side of the fault moves up in relation to the footwall side of the fault.

• where horizontal movements between the fault plane has taken place.
• two types being Right Lateral Fault and Left Lateral Fault

If there is no shear displacement then the fracture in the rock is called a

the direction of compress stress of a volcanoes

expansion result of tension

process of mountain building

meanign of mountain

coming to being

Form when two oceanic plates converge and one is subducted beneath the other

convergence of an oceanic plate and a continental plate because of subduction of the contiental plate

• When two continental plates come together and the are separated by the ocean floor
• the ocean floor subducts and brings the two continental plates together which then collide

result of normal faulting where one block is thrust up and the other thrust down.

is defined as the balance or equilibrium of blocks floating on the upper mantle

The erosion of sediments due to weathering may lower the weight of the rocks and they rebound back as the pressure is released. (like removing the weight from a pillow).

major john wesley powell

colorado river

• present is the key to the past,
• the processes operation on the earth today (earthquakes, volcanoes, erosion, etc.) have been operating on the earth thorough its history

he reverse of uniformitarianism, which means that the processes operating in the past are operating today.

can establish the age of rocks

based on comparison

the sequence of events that took place

putting rocks in their proper sequence of formation

the study of 2 items

• original horizontality
• superposition
• lateral continuity
• cross-cutting
• Inclusion
• Intrusion

that when material was initially deposited on the surface of the earth, it was deposited in a horizontal fashion. The folding-faulting observed in the rocks, was after its deposition.

• the layers below are older than the layers deposited on
• top of them. The oldest is at the bottom and the youngest is at the top.

the original sedimentary layer extends laterally until it tapers or thins out at the edges.

• the disrupted pattern is older than the disruption which
• caused it. When a fault cuts across layers of rocks the fault is younger than the layers that it cuts across.

• the fragments included in the host rock are older than
• the host rock.

abody of rock intrudes another one, the intruding body of rock is younger than the host rock

a surface that represents the gaps in geologic record.

Is the contact representing missing rock strata. The older rocks were eroded away which were parallel to the bedding surface.

• a contact in which the younger strata lie over the older
• ones that are tilted or folded.

erosion surface on a plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rock.

by which rocks are similar against one another, can be within reagon a contient or between continent.

able to trace physically the course of a rock unit.

Correlation between two rock types can be made on the assumption that the two rock types in two different regions were formed at the same time.

The fossils succeed one another in a predictable order.

• If the same fossils are found between two rock types then a correlation between then can be
• established

discovered radioactivity

the age of rocks

Establishing the age of the rock using radioactive elements is

the spontaneous necular decay of certain isotopes

Atoms of the same element having different number of neutrons but the same amount of protons.

The time taken by a given amount of radioactive isotope to be reduced by one half.

50g uranium and 50g lead

how long exposed and intense was exposure

U/Pb, Rb/Sr, K/Ar, Radiocarbon

orignal amount

better perspective regarding the occurrence of geologic events and the ages of materials

observations made by relative dating.

the oldest rock found.

meteorites and lunar rocks

same time

thin gaseous veil which surrounds the earth and is held together by forces of gravity

Is the state of the atmosphere at any given time.

what the weather comditions are

composition of the air is not constant. It varies from location to location and from time to time.

nitrogen 78% oxygen 21%

include water vapor, aerosol, and ozone

is the weight of the air above. As the altitude increases pressure decreases.

temperature

above the mesosphere and regions of increasing temperatures owing to the absorption of solar energy, outermost layer

• above the stratosphere and characterized by
• decreasing temperatures

layer immediately above the troposphere and a region with high temperature owing to the concentration of ozone.

lowermost layer and is characterized by decreasing temperatures with height.

all of earth’s energy comes from the sun

The weather at any time during the year is dependent upon

recieves direct energy from the sun

The earth rotates (or spins) on its own axis

the earths journey around the sun

the eath is tilted at an angle of 23.5 degrees

365.2

90%

dec 21-22

the molecule to molecule transfer of heat

physical mixing involving vertical motion

the transfer of heat to space via electromagnetic radiation

infrared

is a process where light bounces back from an object like a mirror

produces weaker rays that travels in all directions

reflecting property of a surface ex jewlery snow asphalt

light reaches the earth’s surface and the earth radiates energy back into the atmosphere

Very little of that energy escapes and the energy is trapped in the atmosphere

Data compiled by meteorologists involve minimum, maximum and ranges of temperatures

Temperatures-Maximum and minimum temperatures / 2

Daily difference between min and max temp.

averagin daily means

average of monthly means

differenes of highest and lowest monthly means

• latitude
• altitude
• cloud cover
• land
• water

as it increases the differences in yearly range of temperatures increases. The seasons are more pronounced.

• If two cities are at the same location, however, if one is at a higher location than the other, then the city with the higher location, has a more range of temperature. It
• could be much colder or warmer.

have a moderating effect on the weather. They can act as beach umbrellas during the summer and as blankets during the winter.

• Even though two places are almost at the same latitude, but if one is situated close to a body
• of water (Vancouver) and the other is landlocked (Winnepeg), then the one that is situated close to a body of water (Vancouver) will have a mild climate as opposed to the one that is landlocked (Winnepeg), which will have climatic extremes (very cold and extremely warm). E.g. San Francisco (next to an ocean) and Wichita (landlocked