Plate Tectonics Flashcards
T or F
Before the continental drift theory emerged, most geologists believed that ocean basins and continents are stationary and is fixed in position.
T
T or F
The proposal for the continental drift hypothesis began early in the 19th century but has been rejected by the scientific community for 40 years.
F, it is hypothesized in the 20th century, and was rejected for 50 years.
What was the theory that was developed in 1968 that lead to the unfolding of more encompassing explanations.
Theory of Plate Tectonics
Who proposed the continental drift hypothesis, and when?
Alfred Wegener, 1915.
a German meteorologist and geophysicist, who proposed the continental drift hypothesis.
Alfred Wegener
What is the title of the book that Wegener wrote?
The Origin of Continents and Oceans
This hypothesis suggested that a single supercontinent consisting of all Earth’s landmasses once existed.
The Continental Drift Hypothesis
The name of the giant landmass in the continental drift hypothesis.
Pangaea
T or F
Wegener was the first person to conceive of a long-vanished supercontinent.
F, it was Edward Suess.
A distinguished 19th-century geologist, pieced together evidence for a giant landmass consisting of the continents of South America, Africa, India, and Australia.
Edward Suess
T or F
Before Wegener’s hypothesis, Suess already established the similarities between Late Plaeozoic plant fossils of India, Australia, south Africa, and South America, as well as the evidence of glaciation in the rock sequence of the respective continents.
T
What is the title of the book that Edward Suess wrote, and when was the book published?
The Face of the Earth, 1885.
According to Suess’ book, what is the proposed name of the supercontinent composed of the aforementioned southern continents.
Gonwanaland or Gondwana
The American geologist __________ _____________ published a pamphlet in _________ presenting his own theory of continental drift.
Frank Taylor, 1910.
He explained the formation of mountain ranges as a result of the lateral movement of continents. He also envisioned the present-day continents as parts of larger polar continents that eventually broke apart and migrated toward the equator after Earth’s rotation was supposedly slowed by gigantic tidal forces
Frank Taylor
T or F
According to Taylor, such tidal forces were generated when the earth captured the moon approximately 100 million years old.
T
T or F
Taylor’s mechanism regarding the tidal forces is correct.
F, it is incorrect.
He suggested that the Mid-Atlantic Ridge might mark the site along where ancient continents broke apart to form the present day Atlantic Ocean.
Frank Taylor
When was the Mid-Atlantic Ridge discovered and who discovered it?
1872-1876, by the British HMS Challenger expeditions.
Which evidence of the continental drift stated that there are remarkable similarity between the coastlines on opposite sides of the Atlantic Ocean.
The Continental Jigsaw Puzzle
Scientists later determined that a much better approximation of the outer boundary of a continent is the seaward edge of its ___________ _________, which lies submerged a few hundred meters below sea level.
Continental Shelf
T or F
Sir Edward Bullard and two associates constructed a map that pieced together the edges of the continental shelves of South America and Africa at a depth of about 900 meters. The remarkable fit that was obtained was more precise than even these researchers had expected. There are a few places where the continents overlap.
T
The overlaps between the continental margins are caused by what factors?
Stretching and Thinning, and Major River Systems.
Through a review of the literature, Wegener learned that most paleontologists (scientists who study the fossilized remains of ancient organisms) were in agreement that some type of land connection was needed to explain the existence of similar Mesozoic age life forms on widely separated landmasses.
Which evidence does the statement pertain to?
Fossils Match Across the Seas
What are the fossils that was used to furtherly solidify the evidence of the continental drift?
Mesosaurus, Cynognathus, Lystrosaurus, and Glossopteris
An aquatic fish-catching reptile whose fossils are found only in similar nonmarine Permian-age rocks in Brazil and South Africa. If Mesosaurus had been able to make the long journey across the South Atlantic, its remains would likely be more widely distributed.
Mesosaurus
Are land reptiles that lived during the Early Triassic Period. Fossils of _____________ are found in South America and Africa, whereas fossils of _____________ have been recovered from Africa, India, and Antarctica.
Cynognathus and Lystrosaurus
This plant, identified by its tongue-shaped leaves and seeds that were too large to be carried by the wind, was known to be widely dispersed among Africa, Australia, India, and South America. Later, fossil remains of Glossopteris were also discovered in Antarctica.
Glossopteris
Wegener also learned that these seed ferns and associated flora grew only in a ____________ ___________. Therefore, he concluded that when these landmasses were joined, they were located much closer to the South Pole.
Subpolar Climate
Wegener found evidence of 2.2-billion-year-old igneous rocks in Brazil that closely resembled similarly aged rocks in Africa.
Similar evidence can be found in mountain belts that terminate at one coastline, only to reappear on landmasses across the ocean. For instance, the mountain belt that includes theAppalachians trends northeastward through the eastern United States and disappears off the coast of Newfoundland.
Which evidence does the statements pertain to?
Rock Types and Geologic Features such as Mountain Belts
Wegener learned that evidence for a glacial period that dated to the late Paleozoic had been discovered in southern Africa, South America,
Australia, and India. This meant that about 300 million years ago, vast ice sheets covered extensive portions of the Southern Hemisphere as well as India . Much of the land area that
contains evidence of this period of Paleozoic glaciation presently lies within 30 degrees of the equator in subtropical or tropical climates.
Which evidence does the statement pertain to?
Ancent Climates
T or F
One of the main objections to Wegener’s hypothesis stemmed from his inability to identify a credible mechanism for continental drift.
T
T or F
Taylor proposed that gravitational forces of the Moon and Sun that produce Earth’s tides were also capable of gradually moving the
continents across the globe.
F, it was Wegener who proposed.
T or F
Wegener also incorrectly suggested that the larger and sturdier continents broke through thinner oceanic crust, much like ice breakers cut through ice.
T
T or F
In the great debate, there is no evidence that existed to suggest that the ocean floor was weak enough to permit passage of the continents without the continents being appreciably deformed in the process.
T
After the _________ _________ ___, oceanographers equipped with new marine tools and ample funding from the U.S. Office of Naval research embarked on umprecendented period of oceanographic exploration.
World War II
From December 1872 to May 1876, the
______ _____________ _____________ made the first comprehensive study of the global ocean ever attempted.
HMS Challenger expedition
T or F
During the 127,500-kilometer (79,200-mile) voyage, the ship and its crew of scientists traveled to every ocean.
F, they did not travel the Arctic.
During the HMS Challenger expedition, the discovery of a _________ ___________ _______ _________ that winds through all of the major
oceans in a manner similar to the seams on a baseball.
Global Oceanic Ridge System
Was a professor of geology at Princeton University (USA), and became interested in the geology of the oceans while serving in the US Navy in World War II.
Harry Hess
Also called echo sounding, then a new technology, to map the ocean floor across the North Pacific.
Sonar
What is the book that Harry Hess published, and when was the publication?
The History of Ocean Basins, 1962
The main point outlined in the book “The History of Ocean Basins”.
Sea Floor Spreading
T or F
Hess discovered that the oceans were deeper in the middle.
False, the oceans were shallower in the middle.
Harry Hess identified the presence of ______ _________ ________, raised above the surrounding generally flat sea floor abyssal plain by as much as 1.5 km. In addition he found that the deepest parts of the oceans were very close to continental margins in the Pacific with Ocean Trenches extending down to depths of over 11 km in the case of the Marianas Trench off the coast of Japan.
Mid Ocean Ridges
Hess envisaged that oceans grew from their centres, with molten material oozing up from the Earth’s mantle along the mid ocean ridges.
What is the composition of the molten material?
Basalt
T or F
Hess believed that ocean trenches were the locations where ocean floor was destroyed and recycled.
T
According to the plate tectonics model, the uppermost mantle and the overlying crust behave as a strong, rigid layer, known as the
______________.
Lithosphere
The lithosphere is broken into segments commonly referred to as _________.
Plates
The lithosphere, in turn, overlies a weak region in the mantle known as the _____________.
Asthenosphere
What are the 7 major tectonic plates?
North American, South American, Pacific, African, Eurasian, Australian-Indian, Antarctic
What are the 7 Minor Tectonic Plates?
Carribean, Nazca, Philippine, Arabian, Cocos, Scotia, Juan de Fuca
A submerged continent, that is hosted by a minor tectonic plate. It is also referred to as the “lost continent”.
Zealandia
What are the three plate boundaries?
Divergent, Convergent, and Transform
Divergent Plate Boundaries are also referred to as?
Contructive Plate Boundaries
Convergent plate Boundaries are also referred to as?
Destructive Plate Boundaries
Transform Plate Boundaries are also referred to as?
Conservative Plate Boundaries
This is where plates move away from each other .
This are constructive plate boundaries because new ocean floor is generated due to the upwelling of hot material from the mantle.
Also called as “ spreading centers”.
Divergent Plate Boundaries
What are the strcutures that can be found on Diuvergent Plate Boundaries?
Oceanic Ridges (Ocean-Ocean) and Rift Valleys (Continent-Continent)
A deep down faulted structure along the axis of SOME ridge segment.
Rift Valleys
elevated areas of the seafloor that are characterized by high heat flow and volcanism. They are 2 to 3 kilometers higher than the adjacent ocean.
Oceanic Ridges
The _________ _________ _________ is the longest topographic feature on Earth’s surface, exceeding 70,000 kilometers (43,000 miles) in
length.
Global Ridge System
Example of continental rifts.
East African Rift and Red Sea
Example of Ocean Ridges.
Mid-Atlantic Ocean Ridge
Where plate moves towards to each other.
Also called as “ Subduction zones”.
They are sites where lithosphere is descending (beingsubducted) into the mantle.
Oceanic lithosphere is more dense than the
asthenosphere, whereas continental lithosphere is less dense and resists subduction.
Convergent Plate Boundaries
3 types of convergent plate boundaries.
Oceanic-Continental, Oceanic-Oceanic, Continental-Continental Convergence
Example of Oceanic-Continental Convergence
Subduction of Nazca Plate to the South American Plate
Structures and products of Oceanic-Continental Convergence
Structures: Continental Volcanic Arc
Products: Andes Mountains, Mt. Rainier, Mt. St. Helens, Mt. Chimborazo
Example of Oceanic-Oceanic Convergence.
Subduction of the Pacific Plate to the Philippine Plate.
Structures and products of Oceanic-Oceanic convergence
Structures: Island Arcs
Products: Japan, Indonesia, Carribean Islands, Philippines
Example of Continental-Continental convergence.
Convergence of Indian and Eurasian Plate
Structures and products of Continental-Continental convergence.
Structures: Orogenic Belts, Suture Zones
Products: Mt. Everest, Appalachians, Urals, Alps, Himalayas
Characterized by horizontal motion, along transform fault systems (fracture zones), which is parallel to the plate boundary segment that separates two plates.
Transform Plate Boundaries
Example of Transform Plate Boundaries.
The Juan de Fuca and the Pacific Plate sliding past one another.
Structures and products of Transform Plate Boundaries.
Structures: Transform Fault Systems (Fracture Zones)
Products: San Andreas Fault, Alpine Fault, and Anatolian Fault
