Alfred Wegener in Greenland. Plate tectonics is the
theory that Earth’s land masses are in constant motion
. The realization that Earth’s land masses move was first proposed by Alfred Wegener, which he called continental drift.
What did Arthur Holmes propose?
Arthur Holmes began studying physics at the Imperial College of Science in London, but switched to geology before graduating in 1910. In 1913, before he even earned his doctoral degree, he proposed
the first geological time scale
, based on the fairly recently discovered phenomenon of radioactivity.
Who proposed the thermal convection?
It wasn’t until in 1929, shortly before Wegener’s death, that
Arthur Holmes
proposed the idea that the mantle undergoes thermal convection to finally give Wegener’s Continental Drift Theory a viable mechanism.
Who proposed the theory of seafloor spreading?
Harry Hess
: One of the Discoverers of Seafloor Spreading.
How did 21 year old Arthur Holmes revolutionize our understanding of the Earth’s history?
Part of the Earth Inside and Out Curriculum Collection. … He was the first earth scientist to grasp the mechanical and thermal implications of mantle convection, and he widely applied the
newly-developed method of radioactive dating to minerals
in the first attempt to quantitatively estimate the age of the Earth.
Will Pangea ever form again?
The answer
is yes
. Pangea wasn’t the first supercontinent to form during Earth’s 4.5-billion-year geologic history, and it won’t be the last. [What Is Plate Tectonics?] … So, there’s no reason to think that another supercontinent won’t form in the future, Mitchell said.
Why did Pangea break up?
The models show how tectonic plate motion and mantle convection forces worked together to break apart and move large land masses. For example,
Pangaea’s large mass insulated the mantle underneath
, causing mantle flows that triggered the initial breakup of the supercontinent.
What is the evidence that Pangea existed?
Glacial deposits, specifically till, of the same age and structure are found on many separate continents that would have been together in the continent of Pangaea. Fossil evidence for Pangaea includes
the presence of similar and identical species on continents that are now great distances apart
.
Why do tectonic plates move?
The heat from radioactive processes within the planet’s interior causes the plates
to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.
Where is the oldest seafloor found?
The oldest seafloor is comparatively very young, approximately 280 million years old. It is found in
the Mediterranean Sea
and is a remnant of an ancient ocean that is disappearing between Africa and Europe.
What are the two evidence of seafloor spreading?
Harry Hess’s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. This evidence was from the investigations of
the molten material, seafloor drilling, radiometric age dating and fossil ages, and the magnetic stripes
.
What is convection theory?
Heat energy transfers between a solid and a fluid when there is a temperature difference between the fluid and the solid
. This is known as “convection heat transfer”. … The temperature of the solid due to an external field such as fluid buoyancy can induce a fluid motion.
What is convection cell theory?
In the field of fluid dynamics, a convection cell is the phenomenon that
occurs when density differences exist within a body of liquid or gas
. … When a volume of fluid is heated, it expands and becomes less dense and thus more buoyant than the surrounding fluid.
Are tectonic plates?
A tectonic plate (also called lithospheric plate) is a
massive, irregularly shaped slab of solid rock
, generally composed of both continental and oceanic lithosphere. Plate size can vary greatly, from a few hundred to thousands of kilometers across; the Pacific and Antarctic Plates are among the largest.
Did dinosaurs live on Pangea?
Dinosaurs lived on all of the continents
. At the beginning of the age of dinosaurs (during the Triassic Period, about 230 million years ago), the continents were arranged together as a single supercontinent called Pangea. During the 165 million years of dinosaur existence this supercontinent slowly broke apart.
What would happen if Pangea never broke apart?
On Pangea, we might have less diversity of species. The species at the
top of the food chain today would most likely remain there
, but some of today’s animals would not exist in Pangea. They wouldn’t have a chance to evolve. Fewer animals might make it easier to travel.
