LESSON 4: CHANGING POSITION OF CONTINENTS AND OCEANS OVER GEOLOGICAL TIMES
VIDEO LESSON
LESSSON OBJECTIVES
At the end of this lesson, you will be able to:
- Explain the plate tectonic movement
- Produce sketch maps showing the changing location of the Oceans and Continents
- Discuss the changing positions of the Continents and Oceanic basins over the geologic time
BRAINSTORMING QUESTIONS
What do you know about the changing positions of Continents and Ocean basins?
Dear Online Learner! Due to plate movement (tectonics) the position of continents and oceans has been changing several times. For instance, during the Triassic period of the Mesozoic era (210 Ma), the earth’s continents were joined together forming one big continent called Pangaea (meaning the whole of the earth). Pangaea during this time was surrounded by on big water body named Panthalasu.
During the second stage, in the late Triassic period (180Ma), Pangaea started cracking because of continental drift.
In the late cretaceous (65 Ma), the separation between Eurasia and North America increased. These two big continents positioned almost north of the tropic of cancer. Africa, South America, Arabia and India separated and positioned around the equator. Antarctica still placed at the South-Pole. Since the cracks between the separating continents widened, all the free areas were occupied by the Pacific, Atlantic, Arctic and southern oceans.
The Atlantic Ocean covered the area between Africa, Eurasia and the two America’s. The Pacific Ocean occupied the area between the America’s, Eurasia and Australia. The Arctic Ocean covers areas north of the Arctic Circle and areas between North America, Europe and Asia.
The Indian Ocean covers the area between Africa, the Southern Ocean, Asia, and Australia. The Southern Ocean covered areas south of the Pacific, Atlantic and Indian Oceans and the coastal lands of Antarctica. Today, seven continents and five Oceans makes-up the Earth. Most Continents occupy areas north of the equator while oceans dominate the southern hemisphere.
Figure 1.12: Location of continents and Oceans during the late Cretaceous