EARTH SCIENCE Flashcards
The largest division of time
Eon
Internal processes that occur within the earth
Endogenic Process
main endogenic processes
FOLDING & FAULTING or Tectonic Movements
Where do endogenic processes take place?
Plate bounderies
The processes by which folds formed are due to compressional forces
FOLDING
When two forces push towards each other from opposite sides, the rock layers will bend into _____?
FOLDS
2 SCALE FOLDS
large scale folds and small scale folds
It is found mainly along destructive plate boundaries.
Large scale folds
The fracturing and displacement of more
brittle rock strata along a fault plane either caused by tension or compression.
FAULTING
A break in rock along which a vertical or horizontal rock movement has occurred
FAULT
These lines are often lining of weakness which allow molten rock to rise onto the earth surface when there is active volcanic activity nearby
FAULTING
TYPES OF FAULT
Dip-slip fault
Strike-slip fault
occurs when the movement of
the two blocks are vertical.
Dip-slip Fault
A type of fault described by vertical movement.
Dip-slip Fault
occurs when the movement of the two
blocks is horizontal. (Transform or Lateral Movement)
Strike-slip Fault
OTHER ENDOGENIC PROCESSES
Volcanism
Also known as magmatism
VOLCANISM
When folding and faulting occur cracks
o r fr a c t u r e s w h i c h a r e l i n e s o f
weakness are created.
Volcanism
This allows magma to rise along the lines of
weakness and intrude into the crust
Volcanism
Mixture of melted rock and trapped gases that buoyantly rises toward the earth’s surface
Magma
Mixture of minerals and gases and results in
different types of lava flows
Magma
Types of Volcanoes
CINDER CONE
COMPOSITE VOLCANO
SHIELD VOLCANO
simplest type of volcano
CINDER CONE VOLCANO
Rarely rise higher than 300 meters above ground
level
Mostly have bowl-shaped crater at the summit and
rarely rise more than a thousand feet
CINDER CONE VOLCANO
Sometimes called strato volcanoes
COMPOSITE VOLCANOES
Typically steep-sided, symmetrical cones of lava flows, volcanic ash, cinders, blocks and bombs
May rise as much as 8,000 ft
COMPOSITE VOLCANOES
Built almost entirely of fluid lava flows
SHIELD VOLCANO
Flow after flow pours out in all directions from a central summit vent, or group of vents, building a broad, gently sloping cone of flat, domical shape, with a profile much like that of a warrior shield.
SHIELD VOLCANO
An endogenic process which
occurs when there is pressure and heat applied to geologic structures which leads to the formation of metamorphic rocks
Metamorphism
A sudden shaking or
vibration in the earth’s crust.
Earthquake/(Seismic
Activity)
The area beneath the earth’s
surface wherein rocks under
stress undergo breakage
FOCUS (hypocenter)
It is the point of first break in
a fault during an earthquake
FOCUS (hypocenter)
The point on the surface directly above the focus
EPICENTER
are vibrations that move
out from the focus in all
directions during an earthquake
SEISMIC WAVES
an instrument that records and
measures seismic waves
Seismograph
depth from the earth’s
surface to the region where an
earthquake’s energy originates
FOCAL DEPTH
KINDS OF EARTHQUAKES
SHALLOW EARTHQUAKE
INTERMEDIATE EARTHQUAKES
DEEP - FOCUSED EARTHQUAKES
occur within the depth of
the continental crust
have focal depths from
the surface to about 70 km
Shallow Earthquake
occur in the upper part of
the mantle having focal depths
from about 70-300 km
Intermediate Earthquake
occur in the lower part of
the upper mantle
have focal depths from
about 300-700km
Deep Focused Earthquake
Scientists use 2 methods to determine the age of fossils:
Relative and Absolute dating
Determining how old
something is compared to
something else
Relative dating
Use words like “older” or
“younger” instead of exact
numbers
relative dating
Rules of Relative Dating
Law of Superposition
Law of Original Horizontality
Law of Cross-Cutting Relationships
Law of Inclusion
When sedimentary
rock layers are deposited, younger layers
are on top of older deposits.
Law of Superposition
Sedimentary rock layers are deposited horizontally. If they are tilted, folded, or broken, it happened later.
Law of Original Horizontality
If an igneous intrusion or a fault cuts through
existing rocks, the intrusion/fault is
YOUNGER than the rock it cuts through
Law of Cross-Cutting Relationships
If rock or rock fragments are included within another rock layer, the rock fragments must be older than the rock layer they were embedded
Law of Inclusion
A surface that corresponds
with a gap in sedimentation
resulting from nondeposition
or erosion.
Unconformity
Rocks above any
unconformity are ____ than those below it.
younger
Types of unconformity
Angular Unconformity
Disconformity
Nonconformity
The rocks below the unconformity are tilted. The rocks above it are parallel
Angular Unconformity
The bed above and below the surface are parallel. It can be recognized by correlating one area to another and discovering some strata are missing in one area.
Disconformity
Intrusive igneous or metamorphic rocks are overlain by sedimentary rocks. It occurs if the metamorphic and intrusive igneous rocks undergo uplift erosion and the overlain sedimentary rocks.
Nonconformity
Determining how
old something is Use numbers (in
millions of years,
mya)
Only works for
Igneous Rocks
Absolute dating
Determines the specific age of
a fossil
Looks at chemical properties
Absolute Dating
2 types of absolute dating
Carbon-14 (radiocarbon)
Potassium-Argon
Also known as Radiocarbon dating
Carbon-14 (radiocarbon)
Used to date organic substances
Carbon-14 (radiocarbon)
Scientists measure the radiocarbon in the
fossil to determine its age
Can only date specimens up to about
60,000 years old
Carbon-14 (radiocarbon)
Scientists determine the age of the
rock surrounding the fossil to
determine the fossil’s age.
Potassium-Argon Dating
Used only for inorganic substances
(rocks and minerals)
Potassium-Argon Dating
Scientists measure the amount of
argon in the rock to determine its age
Dates rock 60,000 years old and
older
Potassium-Argon Dating
When magma/lava cools,
radioactive elements are
incorporated into the minerals
How Absolute Dating Works
How Absolute Dating Works
- These elements begin to decay at
a known rate starting when the rock
cools - We can measure how much of the
element is left - Tells us how much time has
passed since the rock formed.
No life possible as the Earth initially forms
?
4.6 billion years ago
No life possible as the Earth
initially forms 4.6 billion years
ago.
The Proterozoic Eon
