theory of plate tectonics essay leaving cert

H1 Sample Answer | Plate Tectonics - 2018

Keywords in the question are very useful to highlight because they help shape your answer. The keywords in this question are;

• destructive boundaries.

In your answer, you will need to demonstrate that you understand what a destructive boundary is. You should start by defining destructive boundaries. As there are three types, it would be a good idea to divide your answer into three sections accordingly; this will help you keep to the point.

For each type of destructive boundary, describe its characteristics or main features and define the boundary. Give a step-by-step account of what happens at the boundary, say why it is happening and explain the processes involved at each step.

Support what you are saying with relevant evidence and examples. A diagram would be a great way of supporting your explanation.

Student answer

The earth's crust is broken into plates that move around the mantle. The edges of the plates are called boundaries; they mark the point where plates meet. At destructive plate boundaries, two plates collide and land is destroyed. 2 SRPs Different plate boundaries exist as plate boundaries move by convection currents.

This sentence is a vague statement that would require further discussion and explanation in order to qualify for an SRP.

This student mentioned convection currents which are essential to the movement of the plates which is very relevant to this question. This means that you need to make a big deal about them and you should explain what they are and how they cause plates to collide at destructive boundaries as this will get you marks.

At continental-continental destructive plate boundaries, 2 SRPs - type of destructive boundary fold mountains are formed, e.g. the Himalayas, 2 SRPs - location example formed where the Indian and Eurasian plates 2 SRPs - location example slowly collided over millions of years. 2 SRPs Continental crust is 40-60km thick, made of sial-rich rock, and is older than oceanic crust. The Eurasian plate crumpled and rose to form the Tibetan Plateau 2 SRPs - location example and the Himalayas. When 2 continental plates collide, neither sinks; they squeeze together and are compressed, then buckle upwards and the pressure creates shallow earthquakes. For example, in Pakistan in 2005, a shallow earthquake occurred and 89,000 people died. 2 SRPs Fold mountains are usually made from sedimentary rock as they form underwater. Marine fossils are found in the Himalayas because the rock was underwater before it was uplifted by plate movement. 2 SRPs

I always recommend including a diagram and leaving out some points. Diagrams are handy because they require less writing. Less writing means less time spent which you could use elsewhere to develop points further or add surplus points.

Oceanic-continental destructive boundaries   2 SRPs - type of destructive boundary

Oceanic plates are heavier than continental plates so when they collide, the heavier oceanic plate subducts under the lighter continental plate. 2 SRPs As it moves downwards it melts, turns to magma and moves up through the continental crust, causing an explosive volcano to form, e.g. Mount Saint Helens, USA. 2 SRPs Deep earthquakes are also common at these boundaries because the plate movement is not smooth and they can sometimes get stuck. When they suddenly start moving again the pressure is released as an earthquake. 2 SRPs A trench is created at the junction of two colliding plates. This marks the subduction zone, e.g. Peru-Chile Trench. 2 SRPs The Pacific Ring of Fire is an area that contains 452 active volcanoes at the subduction zone at the edge of the Pacific Plate. 75% of the world’s active volcanoes are here, e.g. Mount Pinatubo and Mount Fuji, Japan. 2 SRPs At the point of collision, the continental plate buckles upwards and fold mountains are formed, e.g. the Andes formed due to the collision between the Nazca plate and the South American plate. 2 SRPs 

At a boundary where two oceanic plates collide, the heaviest one subducts beneath the lighter one and a deep ocean trench forms, like the Mariana Trench in the Pacific ocean. This trench marks where the Pacific plate subducts under the Philippine plate. SRPs - surplus Strong earthquakes can occur at trenches to release pressure, e.g. Japan 2011. They lead to Tsunamis as they happen under the sea. SRPs - surplus The subducted plate sinks and melts, causing raising plumes of magma to break through the crust, creating active volcanoes under the sea. SRPs - surplus The material from the volcanoes builds upon the sea floor until it is visible on the surface to form an island arc, e.g. the Philippine Islands. SRPs - surplus An island arc is a curved line of volcanic islands marking a subduction zone; they are parallel to the ocean trench. SRPs - surplus 

While the answer is well laid out, consider using bullet points/smaller paragraphs containing 2-3 pieces of information to break apart the long paragraphs in each section. This will make it easier for you to see at a glance how many SRPs you have included.

In this answer, there is surplus information. This is good because it acts as a safety net. It is clever to include some extra SRPs just in case the marking scheme changed or one of your other points wasn’t valid.

Just remember to watch your timing to make sure you haven't gone over the 12-15 minute timing recommendation for a 30-mark question.

Location examples = 3 x 2 marks = 6 marks (maximum of 3 examples were allowed by marking scheme @ 2 marks each) Type of destructive boundary identified = 2 x 2 marks = 4 marks (maximum of 2 allowed by marking scheme @ 2 marks each) SRPs = 10 x 2 marks = 20 marks (surplus SRPs were given in this answer) 

Total = 30/30 = 100% = H1

Useful links

SRP stands for 'Significant Relevant Point'. Find out more about SRPs

These essays were reviewed by an experienced teacher of Geography who has corrected the Leaving cert Geography exams

The Types of Plate Tectonics Essay

Introduction, types of plate tectonics, works cited.

Plate tectonics refers to movements on Earth’s surface, that is, the lithosphere. This is a theory in science explaining such movements. The lithosphere is made up of large broken rock masses also referred as tectonic plates (Oreskes 424). These tectonic plates are suspended on molten layer of Earth’s crust that comes immediately below the lithosphere; this layer is called asthenosphere.

Given that the asthenosphere is molten, these plates move on it with ease. The movement occurs at boundaries namely; transform boundaries, divergent and convergent boundaries (Oreskes 16). These three different boundaries give rise to the different forms of plate tectonics known today.

According to United States Geological Survey (USGS), there are three different types of plate movements; that is, divergent, convergent, and lateral plate slipping resulting from the three different plate boundaries that exist. Divergent plate movements occur when two oceanic plate move away from each other to form new oceanic crust at a zone of divergence. The zone of divergence results as the Earth’s crust separates (Earth Science). The separation results from hot magma arising from the magma in the continental mantle. This magma has large pressure that causes the crust to crack and separate.

Convergent plate movements are the opposite of divergent and it occurs when two oceanic plates collide leading to loss of crust at a convergent point. Convergent movements involve collision between two plates and these two plates may be either continental or oceanic (USGS).

Convergent plate movements come after divergent plate movements because after the plates break up in the latter, they meet at another point and collide hence the subduction. On the other hand, lateral slipping occurs when two plates move in opposite direction slipping over each other at a transform boundary. The two plates eventually jerk apart due to pressure that mounts up in the mantle and this causes earthquakes (USGS).

The movement of these plates is facilitated by the fact that they float on the Earth’s molten magma on the region called asthenosphere, which lies, below lithosphere. As aforementioned, lithosphere is the outermost Earth’s crust that human beings can reach. Actually, lithosphere makes the tectonic plates (Rychert and Shearer 496). The molten magma heats up as the core of the Earth heats up which causes convectional currents within the molten magma. As the earth core cools, the molten magma cools and sinks and in the process, it pulls the plates attached to it hence the plate movement.

Earthquakes results from these plate tectonic movements along fault lines. Fault lines are cracks on lithosphere. As tectonic plates move, there is building up of pressure along the fault lines, and when this pressure exceeds the strength of lithosphere, earthquakes result to relieve the pressure mounting in the lithosphere. According to Rychert and Shearer, the lateral plate slipping form of movement is the one that causes many earthquakes around the world (498).

Plate tectonics describes the movement of fragments formed from broken lithosphere.

These fragments are suspended on the asthenosphere, which is molten hence offering good medium of movement. There are three different types of plate tectonics, that is, convergent, divergent, and lateral slipping. These movements cause earthquakes as the lithosphere releases mount up pressure in the Earth’s mantle. Earthquakes result mainly from lateral slipping moving and this occurs along fault lines, which are weak points on the lithosphere.

Earth Science. “Plate Tectonics.” Moorland School. N.d. Web.

Oreskes, Naomi. “Plate Tectonics: An Insider’s History of the Modern Theory of the Earth.” California: Westview Press, 2003.

Rychert, Catherine, & Shearer, Peter. “A Global View of the Lithosphere-Asthenosphere Boundary.” Science Journals. 324(5):5926. 2009.

United States Geological Survey. “ Understanding Plate Motions .” 1999. Web.

• COP28 and Strategic Metanarratives
• Water Distribution System in Boston
• Geology Issues: Earthquakes
• Linking Plate Tectonics and Continental Drift
• Plate Tectonics Theory and Features
• Volcanoes Formed by Hotspots vs. Plate Divergence
• Understanding Plate Tectonics and Earthquakes: Movements, Causes, and Measurement
• Global Warming: Accumulation of Greenhouse Gases
• Global Warming: Reasons, Outcomes, and How to Prevent It
• Recreational Shark Fishing
• Chicago (A-D)
• Chicago (N-B)

IvyPanda. (2018, May 9). The Types of Plate Tectonics Essay. https://ivypanda.com/essays/plate-tectonics/

"The Types of Plate Tectonics Essay." IvyPanda , 9 May 2018, ivypanda.com/essays/plate-tectonics/.

IvyPanda . (2018) 'The Types of Plate Tectonics Essay'. 9 May.

IvyPanda . 2018. "The Types of Plate Tectonics Essay." May 9, 2018. https://ivypanda.com/essays/plate-tectonics/.

1. IvyPanda . "The Types of Plate Tectonics Essay." May 9, 2018. https://ivypanda.com/essays/plate-tectonics/.

Bibliography

IvyPanda . "The Types of Plate Tectonics Essay." May 9, 2018. https://ivypanda.com/essays/plate-tectonics/.

• To find inspiration for your paper and overcome writer’s block
• As a source of information (ensure proper referencing)
• As a template for you assignment

IvyPanda uses cookies and similar technologies to enhance your experience, enabling functionalities such as:

• Basic site functions
• Ensuring secure, safe transactions
• Secure account login
• Remembering account, browser, and regional preferences
• Remembering privacy and security settings
• Analyzing site traffic and usage
• Personalized search, content, and recommendations
• Displaying relevant, targeted ads on and off IvyPanda

Please refer to IvyPanda's Cookies Policy and Privacy Policy for detailed information.

Certain technologies we use are essential for critical functions such as security and site integrity, account authentication, security and privacy preferences, internal site usage and maintenance data, and ensuring the site operates correctly for browsing and transactions.

Cookies and similar technologies are used to enhance your experience by:

• Remembering general and regional preferences
• Personalizing content, search, recommendations, and offers

Some functions, such as personalized recommendations, account preferences, or localization, may not work correctly without these technologies. For more details, please refer to IvyPanda's Cookies Policy .

To enable personalized advertising (such as interest-based ads), we may share your data with our marketing and advertising partners using cookies and other technologies. These partners may have their own information collected about you. Turning off the personalized advertising setting won't stop you from seeing IvyPanda ads, but it may make the ads you see less relevant or more repetitive.

Personalized advertising may be considered a "sale" or "sharing" of the information under California and other state privacy laws, and you may have the right to opt out. Turning off personalized advertising allows you to exercise your right to opt out. Learn more in IvyPanda's Cookies Policy and Privacy Policy .