ertsay Flashcards
The ____ states ocean being that crust formed at mid-ocean ridges and destroyed at deep-sea trenches”.
Sea floor
spreading theory
is a geologic
process of the movement of two oceanic
plates, splitting apart from each other at
a divergent plate boundary.
Seafloor spreading
Seafloor spreading is a geologic
process of the movement of two oceanic
plates, splitting apart from each other at
a
divergent plate boundary.
It results in
the formation of new oceanic crust from
magma that comes from within the
Earth’s mantle along a mid- ocean ridge.
carry heat
from the lower mantle and core to the
lithosphere.
Convection currents
Convection currents also
reutilize ___________ back to the mantle
lithospheric materials
As tectonic
plates gradually distance from each other, heat from the mantle’s convection
currents makes the crust more plastic and less dense. The less-dense material ______,
often forming a mountain or elevated area of the seafloor.
rises
As a result, the crust cracks. Hot magma powered by mantle convection
bubbles up to fill these fractures and spills onto the crust. This bubbled-up magma
is cooled by _________ to form igneous rock. This rock (basalt) becomes a new
part of Earth’s crust.
frigid seawater
As a result, the crust cracks. Hot magma powered by mantle convection
bubbles up to fill these fractures and spills onto the crust. This bubbled-up magma
is cooled by frigid seawater to form igneous rock. This _________ becomes a new
part of Earth’s crust.
rock (basalt)
It is the process by which the ocean floor sinks beneath a deep-ocean
trench and back into the mantle, and allows part of the ocean floor to sink back
into the mantle.
Seafloor Spreading Subduction
is the largest depression of land surface on Earth under an
ocean.
Ocean basin
happens along the boundaries of tectonic plates that
are moving apart from each other. These areas are called mid-ocean ridges.
Seafloor spreading
happens along the boundaries of tectonic plates that are
crashing into each other.
Subduction
In these subduction zones, the __________ moves
underneath, or subducts, the ___________. Ocean basins that experience
subduction, such as the Pacific basin, are shrinking.
heavier plate, lighter one
Oceanic basin landforms have two main characteristics namely:
1) Ocean
basin is a land that exists under an ocean; and 2) It includes all topographical
features.
It is a shallow gently sloping part of the continental crust that borders the
continents. It has an average depth of 130 m, and its width varies from tens of
meters to a maximum of about 1, 300 km.
Continental shelf
It extends from the continental shelf at an average depth of 135 meters.
The base is steeply sloping and occurs at a depth of approximately 2000 meters
that marks the edge of the continents. The width of the slope varies from 20 to 100
kilometers.
Continental slope
The V-shaped canyon that cuts into the continental slope to a depth of up
to 1200 meters. It cuts perpendicular to the running direction of the continental
slope.
Submarine canyon
It is found at the base of the continental slope. The depth ranges from 2000
to 5000 meters deep, and the width is up to 300 kilometers. Continental rise is
created by the merging of accumulated deposit at the mouth of the many
submarine canyons.
Continental rise
It is the canyon’s thick fan-shaped sedimentary deposits.
Abyssal fan
It is found at the base of the continental rise in water, ranging from 4 000 to
6 000 meters deep. Ocean floor accounts for nearly 30 % of the Earth’s surface,
consisting of thin layer of basaltic rock
Ocean floor
This layer combines the rigid
crust plus the upper-most mantle.
Lithosphere:
Partially molten part of
upper mantle. Tectonic plates are able to
move about on top of the softer, partially
molten asthenosphere.
Asthenosphere:
The Core is at the center of the Earth. It is
divided into an inner and outer core.
