1) On the diagram below 1 + 2 represent:

One answer only.

   The outer core and lower mantle 

   The outer core and the transition zone 

   The lower mantle and the transition zone 

   Moho and upper mantle

2) Using the diagram below answer the following questions:

350km

Pyroxene forms a complex solid solution with garnet leading to:
One answer only.

   Octahedral coordination and 25% increase in density of garnet 

   Four fold coordination and 10% increase in density of garnet and pyroxene 

   One quarter of silicon atoms octahedrally co-ordinated and 10% increase in density of pyroxene. 

   Garnet transforms to perovskite structure, pyroxene transforms to spinel structure.

400km

At 400km olivine transforms to:
One answer only.

   Beta phase with spinel structure and becomes 8% more dense 

   Beta phase with spinel structure and becomes less dense. 

   Olivine transforms to a dense phase of garnet. 

   Olivine becomes 25% more dense and transforms to perovskite structure.

500 - 550km

At 500 - 550km:
Choose 3 of the following options.

   Olivine transforms to beta phase with spinel structure 

   Garnet transforms to perovskite structure 

   Spinel transforms to a pervoskite structure 

   Beta phase of olivine transforms to gamma 

   Change in phase of olivine results in a 2% increase in density.

650km

At the 650km discontinuity:
One answer only.

   Spinel structure transforms to perovskite structure and MgO 

   It is too deep, no more transformations are possible. 

   All the minerals have a very compact perovskite structure.

6) Using the diagram below  it is possible to say:

Choose 2 of the following options.

   At low depths and density, basalt has a greater density than undepleted pyrolite mantle. 

   At 650km Harzburgite becomes more dense than basalt and pyrolite less dense than basalt. 

   Between 650 and 800km basalt is less dense than pyrolite.

7) As subducted ocean crust sinks (increase in density on the diagram)

Choose 2 of the following options.

   The basaltic slab becomes less dense than mantle pyrolite in the 650 - 750km range. 

   Upto 650km basalt is less dense than pyroite. 

   In the 650 - 750km range, pyrolite becomes more dense than basalt.

8) Slab pull force is generated due to:
Choose 2 of the following options.

   Transformation of peridotite to eclogite. 

   Thermal currents dragging down the slab. 

   An increase in density of basaltic crust as it moves away from ocean ridges and cools. 

   Transformation of basalt to eclogite.

This test has been created using the CASTLE Toolkit