Plates of the Lithosphere and it's theories part 1 Flashcards
What are the huge fractures in the lithosphere called?
plates
The plates of the lithosphere in the ocean are:
soft (low in silica)
The plates of the lithosphere on continents are:
hard (high in silica)
Alfred Wegener hypothesized a giant super continent from the paleozoic and meozoic era known as:
Pangaea
Continental Drift was a term coined by?
Alfred Wegener
What was Wegener’s four pieces of evidence supporting his idea of continental drift?
Fossils, Fit, Glaciers, and Rock Types
The mechanism behind continental drift was found by:
Author Holmes who named the mechanism Thermal Convection.
What is the basic theory behind Thermal Convection?
Hot magma rises and cold magma sinks.
The huge crack in the Atlantic ocean that is continuously creating new ocean flooring is:
The Mid-Ocean Ridge
What type of rock forms from the Mid-Atlantic Ridge?
Basaltic igneous rock
Mid-Ocean Ridge is:
Large mountainous ridges formed along the bottom of the Atlantic Ocean.
The crust closer to the mid-Atlantic ridge are what in relevance to the crust closer to continents?
(This proves Hess’s theory of the spreading seafloor)
The crust closer to the ridge is newer(younger) in age than those found further away from the ridge.
The explanation of why fossils were where we found them is explained by what theory?
The Plate-Tectonic Theory
Define: Plate-Tectonic Theory
The formation, movement, and destruction of lithospheric plates.
What is the be way of locating the plate boundaries?
Earthquakes, Volcanoes, and mountain ridges mark locations for these.
What are the 3 types of plate movement?
Divergent, Convergent, Transform
Divergent plate movement is defined as:
tensional forces that result in plates moving apart (away from each other)
Pangaea is best described as what type of plate movement?
Divergent Plate Movement
When divergent movement happens on a continent, what is the result?
Rift valleys
ex. Colorado Mountains
What are the three stages o Divergent boundaries?
(1) Rift Valleys
(2) Small seas
(3) Oceans
What place has experienced two of the three divergent boundaries and will experience the third in the future?
Madagascar
A lot of fossils are being found in rift valleys, because the Earth’s crust is being ripped apart. What is a famous rift valley where numerous fossils have been found?
The African Rift Valley
Convergent plate movement is best defined as:
compressional (squeeze together) forces that result in plates colliding with one another.
What are the 3 types of convergent plate boundaries?
Ocean -> Ocean
Ocean -> Continent
Continent -> Continent
What happens in Ocean -> Ocean convergence?
friction creates small segments of a magma source and once it burns through the oceanic crust, volcanoes form resulting in “Island Arcs”
What happens in Ocean -> Continent convergence?
friction creates a heat source as the oceanic crust is toppled by the continental crust resulting in volcanoes on land.
What happens in Continent -> Continent convergence?
all other plates have to adjust to the collision of C -> C
What is an example of C -> C convergence?
The Himalayas and India. small oceanic creatures are found in the sedimentary rocks at the very top of the mountain.
When continents collide, subduction stops, and then what happens to the colliding plates?
crust piles on top of other crust resulting in a way mountains are made.
