What was Pangaea?
According to the continental drift theory, over 300 million years ago, all the continents were joined together forming a single landmass surrounded by water. This landmass is called Pangaea.
List 4 type of evidence which supported continental drift
The continental drift theory supposes that over 300 million years ago, there existed one landmass called Pangaea, this landmass later broke into two forming Laurasia and Gondwanaland. Evidence that supports this theory include:-
Similar plant and animal remains have been found along the continental shores, evidence that all the continents were once a single landmass. For example, paleontologists have found remains of the Mesosaurus reptile in vast Brazil and South Africa (Lutegens and Tarbuck 34).
The facing sides of continents, particularly Africa and South America, when put together geometrically fit each other.
Australia, America, South America, India, Africa, and Arabia have a similar distribution of Carboniferous glacial deposits. This suggests similar climatic conditions, an indication that these continents once existed as a piece.
Sedimentation due to continental rifting; the study of ocean basins indicate the presence of new sediments, which is in line with the drift theory that proposes that as a result of further drifting, the rivers deposits sediments into the newly formed valleys
Explain the three types of plate boundaries
Constructive boundaries occur when tectonic plates move away from each other resulting in the formation of ocean basins that are filled with water or sediments.
Destructive boundaries result where two tectonic plates move towards each other, collide, resulting in the compression, folding or uplifting of the plates.
Conservative boundaries occur where two tectonic plates slide past each other, without creation or destruction of the tectonic plates
Which two plates meet at the following locations? Also, list the type of plate boundary found there
Southern California
Pacific plate and North America plate; Transform boundary
Alps
African Plate and the Eurasian Plate; Destructive boundary
Iceland
Eurasian Plate and North American plate; constructive boundary
Mariana Arc
Pacific plate and Mariana plate; convergent boundary
Andes
Nazca Plate and South American Plate; convergent boundary
Contrast the lithosphere and the asthenosphere
The asthenosphere lies deeper into the crust and has higher temperature materials. These materials are in a plastic state can easily flow.
Whereas;
The lithosphere lies on top of the asthenosphere and has hot materials that are in the solid-state. The materials found in the lithosphere can not flow. The lithosphere forms the plate tectonics that floats on the asthenosphere.
Explain in words a 5th grader could understand what is happening at the East African Rift Valleys
The East African Rift Valleys was formed from tectonic forces pulling away or pushing towards each other. In the process lines of weakness formed in the crust. The middle block then sunk to form the rift floor while the adjoining walls formed the valleys
Explain how deep-ocean trenches are related to plate boundaries. Give an example
Ocean trenches are formed at the convergent boundaries. Relative movement of plates away from each other at the boundary leads to the formation of a deep depression called the Ocean trench. An example is the Mariana Trench in the Pacific Ocean.
What is paleomagnetism?
Palaeomagnetism is the discipline that deals with the study of the Earth’s magnetic field in archeological materials such as rocks to determine the Erath’s magnetic field alignment in the past (Christopherson and Thomsen 12).
Why are the various Hawaiian Islands different ages?
The Hawaiian Islands have different ages because the islands occur in active volcanic areas. The islands were formed from volcanic materials which erupted at different times hence the difference in ages (Christopherson and Thomsen 12).
What is meant by a “magnetic Reversal”?
This refers to a change in Earth’s magnetic field polarity. It leads to a shift in the positioning of the North and South Pole.
How did the Himalayas form?
The Himalayas has formed approximately 50 years ago from the collision of the Indian and Eurasian tectonic plates resulting in the uplifting of the young sedimentary rocks to form the range.
Fossil palm trees have been found in Alaska. Assuming the average temperature of the earth was the same as it is now, explains the discovery.
This could be a result of a change in the earth’s climatic conditions or the rock that bore the fossil palm tree could have moved from another area.
Works Cited
Christopherson, W. Robert and Thomsen Charles E. Applied Physical Geography in the Laboratory for Geosystems: An Introduction to Physical Geography. Upper Saddle River, New Jersey: Pearson Education, 2012. Print.
Lutegens, K. Fredrick and Edward J. Tarbuck. Foundations of earth science. Upper Saddle River, New Jersey: Prentice Hall, 2014. Print.