geology Flashcards
tried to figure out the age of the earth based on biblical research
used genealogy
determined the start of the earth was October 23, 4004 BC
bishop usher
mathematician
assumed that the earth was molten and has cooled since formation
determined the earth was about 100million years old
his data was considered very accurate
lord kelvin
used rock layers
old rocks on bottom of cliff, younger rocks on top
used fossil shapes
old fossils- very simple
young fossils- very complex
earth was much older than 100 million years old
William strata smith
life has evolved from simple organisms to complex
multi-cellular life
what percent is usually killed off during a mass extinction
over 50%
4.6 billion to around 600 million years ago
Precambrian
old life
600 million to 250 million years ago
Paleozoic
middle life
250 to 65 million years ago
Mesozoic
recent life
65 million years ago to the present
Cenozoic
life originates in ocean
Chemically rich areas
black smokers
single-cell organisms
Precambrian
age of invertebrates life flourishes Cambrian explosion life becomes more complex life evolves on land massive extinction and end of the Permian period
Paleozoic
age of reptiles
complex life in ocean and on land
mammals evolve
dinosaurs extinction at end of Cretaceous period
Mesozoic
age of mammals large land mammals hominids evolve now anthropocene age of man
Cenozoic
form of molten rock
igneous
form from heat and pressure
metamorphic
forms from sediments
sedimentary
form deep underground
molten rock called magma
plutonic
form on surface
molten rock called lava
volcanic
form underground intrusive form slowly contains large, visible crystals large plutonic bodies batholiths
plutonic igneous rocks
form above ground lava flows cool quickly contain very small crystals associated with volcanoes
volcanic igneous rock
visible, individual colors-cooled
slowly intrusive
large crystals
no visible individual crystals
cooled quickly
extrusive
small crystals
contains dark minerals
mafic
contains light minerals
felsic
the break down of rock due to exposure to the atmosphere
weathering
name the two types of weathering
mechanical/ physical
chemical
have a high rate of weathering
warm/ moist climates
have a slow rate of weathering
cold/ dry climates
radio metric ages
modern science
rock is broken into smaller pieces
composition doesn’t change
mechanical/ physical
eater gets in cracks and freezes
frost wedging
water gets in the pores spaces and expands
frost heaving
sheets fall off exposed rocks
exfoliation
tree and plant root crack rocks
root wedging
the alteration of minerals through a chemical process
surface area is a factor
chemical weathering
reaction with water
hydrolysis/ hydration
reaction with air
oxidation
reacts with acid
dissolution
dominated by physical weathering
lack of moisture impedes development of acids
arid climates
deserts
tundras
Arctic regions
typical areas for arid climates
dominated by chemical weathering
abundance of moisture and plant material to produce acids
humid climates
rain forests
Equatorial regions
typical areas for humid climates
paleoenvironment
old environment
areas that are deposited
help us unlock the paleoenvironment
separated by energy
depositional environments
far from shore fast flowing water large grains poorly sorted conglomerates high energy
alluvial fan
medium energy sand sized particles moderately to well sorted all the grains are about the same size sandstone
rivers and beaches
a reworking of beach deposits
medium energy
sandstone
deserts
low energy
clay sized particles
well sorted
Shale
ocean bottoms
low energy
fine clay MUDs
Shale
lakes
low energy
coal
swamp
very quiet little sediment most animals are filter feeders and need clean water coral reefs limestone
no energy
list the rocks that are resistant in humid environments
granite quartzite
rivers move sediment downstream
water
moves sediment
wind
moves sediment down slopes
glaciers
average year,y temp
warmer means more weathering
average yearly precipitation
moister means more weathering
most resistant rocks in an arid environment
sandstone granite quartzite limestone marble
least resistant rocks in an arid environment
shale
most resistant rocks in a humid environment
sandstone
quartzite
granite
least resistant rocks in a humid environment
limestone
marble
shale
how have pre-existing rocks changed
through heat and pressure
changes seen in rocks over time
larger crystals
mineral content changes
the original rock that is changed into the metamorphic rock
protolith
magma or lava in contact with over lying rocks
heat
compression of rocks
pressure
magma heats water- new minerals form
hot fluids
for, from intense heat and pressure
associated with mountain building
foliated metamorphic rocks
form from heat
little or no pressure
contact metamorphic rocks
high grade/ rank
has alternating light and dark bands of minerals
gneiss
mid grade/ rank
visible shiny crystals
schist
low grade/ rank
no visible crystals
slightly layered
slate
non-foliated form from contact with a magma body show no evidence of pressure typically one solid color after contain visible crystals
contact metamorphic rocks
metamorphosed limestone
softer than glass
marble
metamorphosed sandstone
scratches glass
quartzite
