ESCI - ROCK BEHAVIORS, PLATE MOVEMENTS, SEAFLOOR SPREADING Flashcards
is a naturally occurring
substance that is an aggregate
of different minerals
that had been fused together.
ROCKS
THREE MAIN TYPES OF STRESS
TENSIONAL STRESS
COMPRESSIONAL STRESS
SHEAR STRESS
Causes rocks to be pulled apart that result to lengthening and break apart. This type of stress can be found at divergent plate boundaries.
TENSIONAL STRESS
Involves forces pulling in opposite directions, which can result in strain that stretches and thins rock
TENSIONAL STRESS
Causes rocks to fold or
fracture. It squeezes rocks
together. It is the most common type of stress in convergent
plate boundaries.
COMPRESSIONAL STRESS
when two plates are pushing toward each other - squeezes rock causing it to fold or break
COMPRESSION
Happens when forces slide
pass each other in opposite
direction which results to
slippage and translation. This
is the most common stress found in
transform plate boundaries.
SHEAR STRESS
involves transverse force; the strain shows up as opposing blocks or regions of material moving past each other.
SHEAR STRESS
formed when rocks experienced compressive stress and deformed plastically. It causes bending of rocks.
GEOLOGIC STRUCTURES
three types of folds:
MONOCLINES, ANTICLINES, SYNCLINES
A simple bend in the rock layers where the oldest rocks are at
the bottom and the youngest are at the top.
MONOCLINE
W is a fold that arches upward where the oldest rocks are found at
the center of an anticline. The youngest rocks are covered over them at the top of the structure..
ANTICLINE
Is a fold that bends downward
which rocks are curved down to a center. .
SYNCLINE
A rock under ample stress can
crack, or fracture. The fracture is
called a joint because there is a
block of rock left standing on
either side of a fracture line.
FAULTS
is the rock that place on top the fault
FOOTWALL
is below the fault.
HANGING WALL
TYPES OF FAULTS
NORMAL FAULT
REVERSE FAULT
STRIKE SLIP FAULT
A dip-slip fault in which the
block above the fault has
moved downward relative to
the block below.
NORMAL FAULT
Are the most common faults at
divergent boundaries. In relation
to the footwall, it develops as the
hanging wall drops down. East
African Rift is one of the examples
of this type of fault.
NORMAL FAULT
Is one in which one side of the fault,
the hanging wall, moves up and over the other side, the foot wall. This movement is caused by compression and is common at tectonic plate boundaries.
REVERSE FAULT
is a reverse fault that is at an incline of less than 45 degrees.
THRUST FAULT
Most common at the convergent boundaries. It forms when the hanging wall moves up. It
creates the worldβs highest mountain ranges such as Himalayas Mountains and Rocky Mountains.
REVERSE FAULT
Type of faults formed when the walls move sideways. It can be either right lateral or left lateral. It is mostly common on transform plate boundaries. The most popular example of this type is San
Andreas Fault.
STRIKE-SLIP FAULT
is caused by a build-up
of stress that is released when two rocks slide past one another.
STRIKE SLIP FAULT
a simple bend on the rock layers
MONOCLINES
formed when rocks experienced compressive stress and deformed plastically
FOLD
A bend that arches upward
ANTICLINES
A rock fracture or cracks due to stress
FAULTS
The most common faults at divergent plate boundaries
NORMAL FAULTS
this fault can be found on convergent boundaries
REVERSE FAULTS
It formed when the walls move sideways
STRIKE SLIP FAULTS
An example of mountain range
HIMALAYAS
The type of fault common on transform plate boundaries
STRIKE SLIP FAULTS
An example of fault at divergent plate boundaries
EAST AFRICAN RIFT
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
It causes rocks to fold or fracture.
COMPRESSIONAL STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
It causes rocks to be pulled apart.
TENSIONAL STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
The common type of stress found on divergent plate boundaries.
TENSIONAL STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
This stress on rocks results to slippage and translation of walls.
SHEAR STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
It occurs on convergent plate boundaries.
COMPRESSIONAL STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
It causes rocks to lengthen and break apart
TENSIONAL STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
This type of stress squeezes rocks together.
COMPRESSIONAL STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
It commonly occurs in transform plate boundaries.
SHEAR STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
It happens when the dominant force is directed away from each
other.
TENSIONAL STRESS
TENSIONAL, COMPRESSIONAL OR SHEAR STRESS?
It develops when the forces are directed towards each other but
not along the same axis.
SHEAR STRESS
FACT OR BLUFF?
The Earthβs crust is divided into large plates that float on the semi-fluid mantle.
FACT
FACT OR BLUFF?
Earthquakes and volcanic activity are often associated with tectonic plate boundaries.
FACT
FACT OR BLUFF?
Tectonic plates only move horizontally, never vertically..
BLUFF - they can move both horizontally and vertically, especially in convergent boundaries
FACT OR BLUFF?
The Himalayas were formed by the collision of the Indian Plate and the Eurasian Plate..
FACT
FACT OR BLUFF?
Divergent boundaries create mid-ocean ridges where new crust is formed.
FACT
FACT OR BLUFF?
All tectonic plates are the same thickness.
BLUFF - they vary in thickness, with continental plates thicker than oceanic plates
FACT OR BLUFF?
Tectonic activity is one of the main drivers of the rock cycle..
FACT
FACT OR BLUFF?
Tectonic plates can move in three ways: toward each other, away from each other, or alongside each other.
FACT
FACT OR BLUFF?
Mountains can form at both convergent and divergent plate boundaries.
BLUFF - mountains mainly form at convergent boundaries, while divergent boundaries often create ridges and valleys
FACT OR BLUFF?
Plate tectonics helps explain the distribution of fossils and similar species on distant continents.
FACT
According to the theory of plate tectonics
The Earth is divided into plates
- Plates are like slabs on the surface of the Earthβs shell or ________
- All of our land and water sit on these _____.
- These plates are constantly in ______.
LITHOSPHERE
PLATES
MOTION
The Earthβs plates move around the planetβs surface at the rate of a ____________ every year!
FEW CENTIMETERS
THREE BOUNDARIES CREATED AS THE PLATES MOVE
CONVERGENT
DIVERGENT
TRANSFORM
Converge = ___________
TO COME TOGETHER
_______ boundaries occur when plates move towards one another.
CONVERGENT
Around 55 million years ago, two large landmasses, India and Eurasia, collided with each other, resulting in the Himalayas. This is called ______________ convergence.
CONTINENTAL-CONTINENTAL
Sometimes, one plate dives beneath the other. This is called an __________ convergence, and results in the formation of deep trenches like the Mariana Trench.
OCEAN-OCEAN
Diverge =
MOVE AWAY OR EXTEND IN DIFFERENT DIRECTIONS
_________ boundaries occur when two tectonic plates move away from each other.
DIVERGENT
When two lithospheric plates are spread apart, it is common for new crust to form as molten material rises to the surface. The __________ is formed in this process.
MID-ATLANTIC RIDGE
Transform =
to change
___________ boundaries grind past each other without going up or down.
TRANSFORM
Transform plate boundaries are capable of triggering devastating earthquakes. A famous example is the _____________ in California.
SAN ANDREAS FAULT
teaches us that plates are constantly shifting
PLATE TECTONICS
are where sections of the Earthβs crust fit together
PLATE BOUNDARIES
3 TYPES OF BOUNDARIES
convergent, divergent, and transform
a device that bounces sound waves off underwater objects and then record the echoes of these sound waves
SONAR
the tallest mountain and deepest canyons are found on the_________ ; far taller and deeper than any landforms found on the continents.
OCEAN FLOOR
During World War II, using the _________ that were attached to ships scientists discovered a lot about the magnetic properties of the seafloor.
MAGNETOMETERS
TRUE OR FALSE
Geologists say that polarity is normal when the north and south are aligned while when they are in the opposite position, the polarity is reversed
TRUE
They found that _______ _______ in the seafloor was normal at mid-ocean ridges but reversed in symmetrical patterns away from the ridge center.
MAGNETIC POLARITY
Different features of seafloor
CONTINENTAL SHELF CONTINENTAL SLOPE
ABYSSAL PLAIN
MID-OCEANIC RIDGE
SEAMOUNT
TRENCH
In 1960, the American geophysicist, ____________ explained how the convection currents in the Earthβs interior make the seafloor spread.
HARRY HESS
_________carry heat from the molten materials in the mantle and core towards
the lithosphere. These current ensures that the βrecycledβ materials formed in the lithosphere were back to the
mantle.
CONVECTION CURRENT
In this recycling process which was later named as _____________, the magma moves up from the mantle and erupts as pillow lava. This forms new _______ at the ridge. Then, as new oceanic crust form, it pushes the older crust aside.
SEAFLOOR SPREADING
OCEANIC CRUST
TRUE OR FALSE
This means that the nearer the ocean floor to the oceanic ridge, the older it is compared to the
ones farther from the ridge.
FALSE - the oceanic floor near the oceanic ridge are YOUNGER
This crust eventually subducts at the deep ________ and melts back into the mantle. Then the seafloor spreading continues as a βrecyclingβ process.
OCEAN TRENCHES
three evidence that support the idea that seafloor is continuously spreading.
(a.) Evidence from molten materials
(b.) Evidence from magnetic strip
(c.) Evidence from drilling sample
rocks shaped like pillows (rock pillows) show that molten materials have erupted again and again from cracks along the mid ocean ridge and cooled quickly.
Evidence from molten materials
rocks that make up the ocean floor lie in a pattern of magnetized stripes which hold a record of the reversals in magnetic field
Evidence from magnetic strip
core samples from the ocean floor show that older rocks are found farther from the ridge; youngest rocks are in the mid-ocean ridge
Evidence from drilling sample
The longest chain of mountains in the world is the system of
MID-OCEAN RIDGES
is a device that bounces sound waves off underwater objects and then records the echoes of these
sound waves.
SONAR
________ allows part of the ocean floor to sinkback into the mantle, over tens of millions of years
SUBDUCTION
TRUE OR FALSE
The processes of subduction and sea-floor spreading can change the size and shape of the oceans. Because of these processes,
the ocean floor is renewed about every 200 million years.
TRUE
TRUE OR FALSE
The Pacific Ocean is shrinking. Its many trenches are swallowing more ocean crust than the mid-ocean ridge is producing. The Atlantic Ocean is expanding. In most places, the oceanic crust of the Atlantic Ocean is attached to continental crust. As the Atlanticβs floor spreads, the continents along its edges also move.
TRUE
Because of _______ forces and
processes, the supercontinent breaks apart and ocean basins are formed.
TECTONIC
The _________ cover the largest area of the earthβs surface. All of them were formed from volcanic rock that was released from the fissures that is located at the mid-ocean ridges, which is an underwater mountain range formed by plate tectonics.
OCEAN BASINS
The world ocean is divided into the
North and South Pacific, North and South Atlantic, Indian, and Arctic Oceans
largest, deepest, and oldest existing ocean basin. More trenches, and more frequent tsunamis happen here. It has been shaped by plate tectonics.
PACIFIC OCEAN basin
second largest ocean basin
ATLANTIC
third biggest ocean basin
INDIAN
SMALLEST OF THE EARTH;S OCEAN BASIN IS AND COVERED BY ICE
ARTIC
Partly shallow extension of the continent underwater.
CONTINENTAL SHELF
Transition zone of continental shelf and deep ocean floor. It starts from oceanic crust to continental crust.
CONTINENTAL SLOPE
It is where the ocean begins. All basaltic and oceanic rocks are found here. It is the place where
the sediments from land are washed. The continental margin starts from continental helf up to continental rise.
CONTINENTAL RISE
The flattest part of the ocean. 50 % of the earthβs surface is being covered by this plain.
ABYSSAL PLAIN
Itβs not just a piece of land floating up in the middle of the sea, it is part of the ocean basin that extends up
from the ocean floor.
ISLAND
It is an undersea mountain. The erosion caused by waves destroyed the top of a seamount which caused it to be flattened.
SEAMOUNT
It is the deepest part of the ocean.
TRENCH
The seafloor mountain system which is situated in the middle of the ocean basin. It is where
upwelling of magma happens which causes the sea floor to spread.
MID-OCEANIC RIDGE
cycle that explains the process of the opening (beginning) and the closing (end) of an ocean which is driven by Plate Tectonics
The Wilson Cycle
He named The Wilson Cycle
J. Tuzo Wilson
6 stage of the Wilson Cycle
- Embryonic Ocean Basin
- Juvenile Ocean Basin
- Mature Ocean Basin
- Declining Ocean Basin
- Terminal Ocean Basin
- Suturing (Continental collision)
β Motion: Uplift
β Complex system of linear rift
valleys on continent
Emrbyonic
East African Rift Valleys
Embryonic
β Motion: Divergence (Spreading)
β Narrow seas with matching coasts
juvenile
Red Sea
JUVENILE
β Motion: Divergence (Spreading)
β Ocean basin with continental
margins
MATURE
Atlantic and Arctic Oceans
MATURE
β Motion: Convergent (Subduction)
β Islands arcs and trenches around
basin edge
DECLINING
Pacific Ocean
DECLINING
β Motion: Convergent (Collision and
Uplift)
β Narrow, irregular seas with young
mountains
TERMINAL
Mediterranean an Seas
TERMINAL
β Motion: Convergence and Uplift
β Young mature mountain belts
Whatβs More The Ocean Basin to
SUTURING
Himalayas Mountains
SUTURING
TRUE OR FALSE
New ocean floor seems to form at same rates in different ocean basins and over time
FALSE - They form at different rates
researchers themselves explore ocean basins in special submarines called
SUBMERSIBLES
is normally found rising the ocean floor at the center of the ocean basins.
MID-OCEAN RIDGE
