Lesson Notes By Weeks and Term - Senior Secondary 1

TERM – 2^ND TERM

WEEK TWO

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Geography

Topic: PLATEAU 2

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Explain the mode of formation of each type of plateau.
2. State the uses or advantages of plateau.
3. Analyse the effects or disadvantages of plateaux.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

PLATEAU 2

Mode of formation of Volcanic plateaux

 Volcanic plateaus typically form through the accumulation of numerous volcanic eruptions over a long period. These eruptions often involve the outpouring of large volumes of basaltic lava, which spreads out horizontally and solidifies. The repeated layers of lava build up to create a broad, elevated plateau. The Deccan Plateau in India and the Columbia Plateau in the United States are examples of volcanic plateaus formed in this manner.

Mode of formation of Tectonic plateaux

Tectonic plateaus form through complex geological processes involving the Earth's lithospheric plates. One common mechanism is the interaction of tectonic plates leading to uplift and the subsequent development of elevated landmasses. This can occur through continental collisions, where two plates converge, causing compression and uplift of the crust, forming plateaus.

Another way is through the stretching and thinning of the Earth's crust, known as extensional tectonics. As plates pull apart, rift zones may develop, leading to the uplift of plateaus. Additionally, hotspot activity beneath the crust can contribute to plateau formation. Magma rising from the mantle can create volcanic plateaus or uplift existing landmasses.

The Tibetan Plateau, often referred to as the "Roof of the World," is an example of a tectonic plateau formed through the collision of the Indian and Eurasian plates, resulting in uplift and the formation of this extensive highland.

Mode of formation of dissected plateaux

Dissected plateaus form through a combination of erosion and tectonic processes. Initially, tectonic forces uplift a plateau, creating a relatively flat or gently sloping elevated landmass. Subsequently, various agents of erosion, such as rivers and weathering, work on the plateau surface, cutting into the rock layers.

Over time, these erosional forces create a network of valleys and channels, dissecting the plateau into a more intricate landscape of ridges and canyons. The specific patterns and features depend on factors like the type of rock, climate, and the intensity of tectonic activity in the region.

The Appalachian Plateau in the eastern United States is an example of a dissected plateau, formed through a combination of tectonic uplift and erosional processes over millions of years.

Mode of formation of lava plateaux

Lava plateaus form when large volumes of basaltic lava erupt from fissures or vents in the Earth's crust and cover extensive areas. The process typically involves the following steps:

1. Lava Eruption: Basaltic lava, which is low in viscosity and rich in iron and magnesium, erupts from the Earth's mantle through long cracks in the crust known as fissures or from central vents.
2. Effusive Eruptions: The lava flows out in a relatively gentle and continuous manner, allowing it to cover vast areas. This type of eruption is known as effusive, contrasting with explosive eruptions that produce pyroclastic materials.
3. Lava Spreading: The lava spreads horizontally over the surrounding landscape, forming thick, extensive layers. The low viscosity of basaltic lava allows it to cover large distances before solidifying.
4. Solidification: As the lava cools, it solidifies, creating a basaltic plateau with a relatively flat or gently undulating surface. The repeated eruptions and layering of lava contribute to the thickness of the plateau.

The Columbia Plateau in the northwestern United States and the Deccan Plateau in India are examples of lava plateaus formed through such volcanic processes.

Uses/advantages of plateaux

Plateaus offer various uses and advantages:

1. Many plateaus have fertile soils due to the accumulation of volcanic or sedimentary deposits. These areas can support agriculture, contributing to food production.
2. Plateaus often feature diverse ecosystems due to variations in altitude, climate, and soil types. This can provide habitats for a wide range of plant and animal species.
3. Plateaus are often the source of rivers and streams, contributing to regional water systems. The elevation can lead to the creation of watersheds that supply water for agricultural and urban use downstream.
4. Scenic plateaus attract tourists and provide opportunities for recreational activities such as hiking, camping, and sightseeing.
5. Some plateaus contain valuable mineral deposits. Mining activities on plateaus can contribute to economic development by extracting resources like coal, minerals, and metals.
6. Plateaus with consistent winds can be suitable locations for wind farms, contributing to renewable energy generation.

Effects/disadvantages of plateaux

1. Plateaus can pose challenges such as limited agricultural productivity due to rocky terrain, difficulties in constructing infrastructure and transportation networks, and challenges in accessing water sources.
2. Plateaus may be more susceptible to erosion, and their elevated locations can expose them to harsh weather conditions, affecting the livelihoods of communities settled on them.

EVALUATION: 1. Identify 4 uses of plateau.

2. Give 2 effects of plateau.
3. Discuss the mode of formation of lave plateaux.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively