Geological Timescales & Plate Tectonics Day

Welcome to Physical Geography Days - In Progress!

Objectives:

To explore physical geography relating to: geological timescales and plate tectonics; rocks, weathering and soils; weather and climate, including the change in climate from the Ice Age to the present; and glaciation, hydrology and coasts.

Session One - Continental Drift

Continental Drift Theory

Continental drift is the hypothesis that the Earth's continents have moved over time. They appear to have "drifted" across the ocean bed.

The idea was first put forward by Abraham Ortelius in 1596, and more fully developed by Alfred Wegener in 1912.

Uncover Alfred Wegener's theory of continental drift through biological and geological evidence and the theory of plate tectonics here.

Learn more here and complete a simple test here.

Pangaea

Pangaea was a supercontinent.

It consisted of a northern part, Laurasia, and a southern part, Gondwana.

Laurasia

Laurasia was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago. It is broadly North America, Europe, and South Asia.

Gondwana

Gondwana contained the southern continents—South America, Africa, India, Madagascar, Australia, and Antarctica.

Gondwana collided with North America, Europe, and Siberia to form the supercontinent of Pangea.

 

Fossil Ranges

Another argument for continental drift theory is the fossil ranges that have been identified. If the continents are put together in the way that they seem to fit, there seem to be four fossil types which form continuous patterns across continental boundaries. The activity at the end of this session will help you to visualize this more clearly.

 

Activity

Cut out the countries and continents of Pangaea and rearrange them to make the supercontinent. Identify the fossil ranges and colour code them in some way. Label the countries (cities if you want to) as they are called today.

Download (PDF, 796KB)

Session Two - Plate Tectonics

The Vocabulary of Plate Tectonics:

    • Earth’s Crust The outer most layer of the Earth. This is the layer we walk on.
    • Tectonic Plates Slowly moving pieces of Earth’s crust.
    • Convection Movement caused by warm fluids rising and cooler fluids sinking.
    • Divergent Boundary A boundary of two tectonic plates where the plates move away from each other.
    • Convergent Boundary A boundary of two tectonic plates where the plates move towards each other.
    • Transform Boundary A boundary of two tectonic plates where the plates slide past each other.
    • Subduction When one tectonic plate converges under another due to density differences.
    • Uplift When two tectonic plates slowly crash into each other and mountains are formed.
    • Pangea The name given to the super continent from the well-supported theory that all the continents used to be connected as one.
    • Seismologist A scientist who studies earthquakes.

Take this vocabulary QUIZ!

Plate Tectonics

Plate tectonics is a scientific theory that explains how major landforms are created including mountain building events, volcanoes, and earthquakes.

In plate tectonics, Earth’s outermost layer made up of the crust and upper mantle is broken into large rocky plates.

These plates lie on top of a partially molten layer of rock.

The plates move relative to each other at different rates, from one to six inches per year. This interaction of tectonic plates is responsible for many different geological formations such as the Himalaya mountain range in Asia, the East African Rift, and the San Andreas Fault in California, United States.

<resource_carousel.datastructures.RCItem object at 0x7f016ede47f0>San Andreas Fault

Tectonic plate boundaries, like the San Andreas Fault can be the sites of mountain-building events, volcanoes, or valley or rift creation.

 

 

 

Study the Information here and take this test.

Tectonic Plates Video For Kids | 6th, 7th & 8th Grade Science

There is more information and an informative video on this page.

Activity - Tectonic Plate Vocabulary:

Download (PDF, 582KB)

Activity - Tectonic Plate Map:

Use the following list of major tectonic plates and this map or this one to label the plates on the world map.

Major plates

These plates comprise the bulk of the continents and the Pacific Ocean. For purposes of this list, a major plate is any plate with an area greater than 20 million km2.

  • African Plate – A major tectonic plate underlying Africa west of the East African Rift – 61,300,000 km2
  • Antarctic Plate – Tectonic plate containing Antarctica and the surrounding ocean floor – 60,900,000 km2
  • Eurasian Plate – Tectonic plate which includes most of the continent of Eurasia – 67,800,000 km2
  • Indo-Australian Plate – A major tectonic plate formed by the fusion of the Indian and Australian plates – 58,900,000 km2 often considered two plates:
    • Australian Plate – Major tectonic plate, originally a part of the ancient continent of Gondwana – 47,000,000 km2
    • Indian Plate – A minor tectonic plate that got separated from Gondwana – 11,900,000 km2
  • North American Plate – Large tectonic plate including most of North America, Greenland and part of Siberia. – 75,900,000 km2
  • Pacific Plate – Oceanic tectonic plate under the Pacific Ocean – 103,300,000 km2
  • South American Plate – Major tectonic plate which includes most of South America and a large part of the south Atlantic – 43,600,000 km2

Download (PDF, 694KB)

Session Three - Mantle Convection

 

The earth has four key layers: inner core, outer core, mantle and crust.

Mantle Convection

Arthur Holmes proposed mantle convection for the method of continental drift about one hundred years ago. He saw that the problem with the theory of continental drift lay in the mechanism of movement.
He proposed that Earth's mantle contained convection cells that evaporated radioactive heat and moved the crust at the surface.
The idea of continental drift has since been incorporated into the science of plate tectonics.

Activity - Convection in The Earth's Mantle:

Create your own convection model.

 

Session Four - Geological Timescales

Key ideas

  • Earth was created 4.5 billion years ago.
  • Over the past 4.5 billion years, geologists have identified a series of time periods that have different names and classifications. There are 4 'Eons', split into Eras, Periods and Epochs.
  • We are currently living in the Phanerozoic Eon (the planet has been in this Eon for 541 million years), Cenozoic Era (which started 66 million years ago), Quaternary Period (started 2.5 million years ago), Holocene Epoch (started 11.8 thousand years ago).
  • Some geologists have suggested that the Holocene Epoch has ended and we are now in the 'Anthropocene', characterised by human impact on the planet.
  • Tectonic processes have changed the distribution of landmasses.
  • Life appeared on Earth at least 3.5 billion years ago as single-celled organisms. Plant life adapted to photosynthesise, which added oxygen to the atmosphere and oceans.
  • The first marine creatures formed in the oceans and through the processes of succession and evolution adapted to life on land.
  • Dinosaurs were the dominant land species during the Mesozoic Era. The end of this Era was marked by one of five mass extinction events that have occurred in Earth history.
  • Mammals evolved after the time of the dinosaurs, and large-scale landscape, ocean and climate changes enabled mammals to exploit environments across the planet.
  • Humans evolved from apes in central Africa 2 million years ago then migrated across the world.

Download (PDF, 154KB)

Activity:

Make a Fact Card about a dinosaur, prehistoric mammal, plant etc... (Half letter size, double-sided).

It might look something like this on one side:

  • Research it using any sources you wish:
    • https://www.infoplease.com/math-science/earth-environment/table-of-geological-periods
    • https://www.britannica.com/event/Paleolithic-Period
    • https://legacy.calacademy.org//human-odyssey/map/
  • Include: 
    • dates (period, epoch, and era etc...)
    • scientific and common names
    • sizes and other physical features
    • interesting information i.e reproduction, diet, habitat
    • images
    • a list of the sources you used (list or books or websites)

Wrap Up:

Collate your Learnings:

Must include:

Pangea Map with key

Plate Tectonics Vocabulary

Tectonic Plate Map

Paleolithic Period Factcard

Could include:

Fossil Range printout

Plate Tectonics Test Printout 1

Photos / description of Mantle Convection

Plate Tectonics Vocabulary Test Printout

Plate Tectonics Test Printout 2

Geological Timescales Printout

End of Unit Quiz Results

Quiz

Plate Tectonic Unit Quiz