Download appendix 1

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Welcome
This is a document to explains the chosen concept to the
animator.
This will take you through a 5 section process to provide the
necessary details to the animator before starting the animation.
The legend on the left will indicate the current status of the
document. The big Black coloured number will denote the current
section, the Grey color would denote the completed sections,
and the Turquoise color would denote the remaining sections.
The slides having yellow background (like this one) are the
'Instruction slides'
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Subduction Mechanism
Subduction zones exist at convergent plate boundaries where one plate of oceanic lithosphere
converges with another one. The down-going slab- the subducting plate- is overridden by the leading
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edge of the other plate. The overriding continental plate is lifted up, and a mountain range is created.
The oceanic plate bends and plunges steeply through the asthenosphere. Sinking of the oceanic plate
due to contrast of density between the cold and old lithosphere and the hot asthenospheric mantle
wedge, is one of the strongest forces needed to drive the plate and is the dominant mode of mantle
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convection.
Related LOs:
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> Prior Viewing: Plate tectonics/ Movement
> Future Viewing :
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Course Name: Plate Tectonics
Level: Post graduation
Author: Arpita Roy
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Mentor: Prof. Soumyajit Mukherjee
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*The contents in this ppt are licensed under Creative Commons Attribution-NonCommercial-ShareAlike 2.5 India license
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Learning objectives
After interacting with this Learning Object, the learner will be able to:
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Describe the geological phenomenon in the Subduction zone
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Master layout or diagram
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Make a schematic diagram of the concept
Explain the animator about the beginning and ending of the
process.
Draw image big enough for explaining.
In the image, identify and label different components of the
process/phenomenon. (These are like characters in a film)
Illustrate the basic flow of action by using arrows. Use BOLD
lines in the diagram (minimum 2pts.)
In the slide after that, provide the definitions of ALL the labels
used in the diagram
You may have multiple master layouts.
• In this case, number the master layout.
(e.g. Master layout 1, 2, 3…)
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Keywords/Definitions
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Converging continental plate: In plate tectonics, a convergent boundary, also known as a
destructive plate boundary, is an actively deforming region where two (or more) plates or
fragments of lithosphere move toward one another and collide. As a result of pressure,
friction, and plate material melting in the mantle, earthquakes and volcanoes are common
near convergent boundaries.
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Accretionary wedge : An accretionary wedge or an accretionary prism is formed from
sediments that are accreted onto the non- subducting tectonic plate at a convergent plate
boundary. Most of the material in the accretionary wedge consists of marine sediments
scraped off from the down going slab of oceanic crust, but in some cases includes the
erosional products of volcanic island arcs formed on the overriding plate.
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Forarc basin: A forearc or forarc, also called arc-trench gap, is a depression in the sea floor
located between a subduction zone and an associated volcanic arc. It is typically filled with
sediments from the adjacent landmass and the island arc in addition to trapped oceanic
crustal material.
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Keywords/Definitions
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Magmatic arc or Volcanic arc: This is a result of the subduction of an oceanic tectonic plate
under another tectonic plate, and often parallels an oceanic trench. The oceanic plate is
saturated with water, and volatiles such as water drastically reduces the melting point of the
mantle. As the oceanic plate is subducted, it is subjected to progressively increasing
pressures with increasing depth. This pressure squeezes water out of the plate and
introduces it to the mantle. Here the mantle melts and forms magma at depth under the
overriding plate. The magma ascends to form an arc of volcanoes parallel to the subduction
zone
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Back arc basin: These are submarine basins associated with island arcs and subduction
zones. This is the region landward of the volcanic chain on the other side from the
subduction zone
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Convergence: Convergence is a phenomenon in which, two plates come together and one
plate will be going downward respect to the another one.
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Master layout: 1
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Volcanic
arc
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Oceanic
crust
Oceanic
plate
Volcano
Trench
Continental
crust
Magma
ascension
Mantle
lithosphere
Mantle
(asthenosphere)
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Fig. 1
In our considerable phenomenon , subduction process
involves the convergence between the oceanic plate and
continental plate and results volcanic arc.
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Master layout: 2
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2
Continental
plate
Lithosphere
Oceanic
plate
Oceanic
plate
Asthenosphere
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Island
arc
Trench
Lithosphere
Asthenosphere
Fig. 2
In our considerable phenomenon, subduction process
involves convergence of oceanic and oceanic plate and
results Island arc.
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The blocked
portion involves the
uprising magma
(shown by black
arrow)
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Explain the process
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In this step, use an example to explain the concept. It
can be an analogy, a scenario, or an action which
explains this concept/process/topic
Try to use examples from day-to-day life to make it
more clear
You have to describe what steps the animator should
take to make your concept come alive as a series of
moving images.
Keep the examples simple to understand, and also to
illustrate/animate.
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Analogy
Description of the event in brief: The two solid slabs are subjected to
head-on collision but due to density difference, one slab goes down under
the second one, which results in the formation of different tectonic
features.
Analogy of the above said event: Scraping of a cream cake with a knife is
analogous to the formation of accretionary prism and fore arc basin.
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Stepwise description of process
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The goal of the document is to provide instructions to an
animator who is not a expert.
You have to describe what steps the animator should take to
make your concept come alive as a moving visualization.
Use one slide per step. This will ensure clarity of the
explanation.
Add a image of the step in the box, and the details in the table
below the box.
You can use any images for reference, but mention about it's
copyright status
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The animator will have to re-draw / re-create the drawings
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Add more slides as per the requirement of the animation
Step: 1, Volcanic arc formed by
oceanic-continental subduction
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Volcanic
arc
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Oceanic
crust
Volcano
Trench
Continental
crust
Oceanic
plate
Magma
ascension
Mantle
lithosphere
Mantle
(asthenosphere)
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Fig. 1
Description of the action
Audio narration
1) Show that the oceanic plate is
going towards downward
direction (as shown by black
arrows)
2) The down-going oceanic
plate makes an angle with the
mantle lithosphere (almost
45⁰)
3) Show the magma (shown by
orange colour) is going
upwards by black arrow and
forms volcanic arc ( denotes
by area little bit elevated)
4) Time duration for this event
will be 10-15 seconds
In our considerable phenomenon ,
subduction process involves the
convergence between the oceanic
plate and continental plate and
volcanic arc is the resultant event.
Text to be displayed
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Step: 2, Island arc formed by
oceanic-oceanic subduction
Trench
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Continental
plate
Lithosphere
Oceanic
plate: 2
Oceanic
plate: 1
Asthenosphere
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Island
arc
Lithosphere
Asthenosphere
Fig. 2
Description of the action
Audio narration
1) Show the lithospheric oceanic
plate: 1 is going downward (as
shown by yellow arrows)
2) Another oceanic lithospheric
plate : 2 is coming above the
former one (shown by green
arrows)
3) Show the uprising (shown by
black arrow) magma (by red
colored material) which results
island arc
4) Time duration for this event
will be 10-15 seconds
In our considerable phenomenon,
subduction process involves
convergence of oceanic and
oceanic plate. Island arc is the
resultant event.
Text to be displayed
The blocked
portion involves the
uprising magma
(shown by black
arrow)
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Animation design
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Please see the design template provided in the next
slide.
This is a sample template, and you are free to change
as per your design requirements.
Try and rename the tabs / buttons / sections /
subsections as shown in the template.
Slide 3
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Use ‘callouts’ as shown above to explain the source of
content. Ex: If the call out is placed at the Tab 01,
and you want the content to be taken from slide 3 of
this presentation, then place this callout on the Tab
01, and write ‘Slide 3’ inside the callout.
Animation design
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Volcanic
arc
Interactivity
area
Volcano
Oceanic
crust
Trench
Start
Continental
crust
Oceanic
plate
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Magma
ascension
Definitions
Model 1
Model 2
Mantle
(asthenosphere)
Mantle (asthenosphere)
Summary
Replay
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Fig. 1
First show the movement of the oceanic plate. Then after, the movement of magma ascension. Both of these activities
Will take 10-15 seconds.
Credits
Animation design
Interactivity
area
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Island arc
Trench
2
Continental
plate
Oceanic
plate: 1
Lithosphere
Oceanic plate: 2
Lithosphere
Asthenosphere
Asthenosphere
Start
Definitions
Model 1
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Model 2
Fig. 2
Summary
Replay
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show the downward movement of the oceanic plate: 1 ( shown by yellow arrow), then after overriding movement of the oceanic plate: 2( shown by green arrow) over the oceanic
Plate: 1. Show the uprising movement of the magma (red triangular portion) and finally the formation of Island arc. The
Time duration for whole event will be 10-15 seconds.
Credits
APPENDIX 1
Self- Assessment Questionnaire for Learners
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Please provide a set of questions that a user can answer based
on the LO. They can be of the following types:
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These questions should be 5 in number and can be of
objective type (like MCQ, Match the columns, Yes or No,
Sequencing, Odd One Out).
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The questions can also be open-ended. The user would be
asked to think about the question. The author is requested to
provide hints if possible, but a full answer is not necessary.
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One can include questions, for which the user will need to
interact with the LO (with certain parameters) in order to
answer it.
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It is better to avoid questions based purely on recall.
APPENDIX 1
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Questionnaire:
1) How would be thermal structure of the down going slab during subduction process?
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a) As it going towards depth, the temperature increases
b) Temperature would not vary
c) Temperature will decrease
d) Temperature does not matter with the distance of the down going slab
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2) What is the angular relation between the down going plate with respect to the uppermost layer of the Earth?
a) 0⁰
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b) 45⁰
c) 90⁰
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d) 60⁰
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Questionnaire:
3) In case of subduction which portion (the portion of Earth) will go down and why?
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a) Asthenosphere, as it becomes more denser
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b) Lithosphere, as it becomes cool and more denser
c) Lithospheric plate, due to overburden pressure
d) None of these.
4) What are reasons behind the rising of mid oceanic ridge or its topographic elevation?
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a) Due to buoyancy of the thinner lithospheric plate
b) The body force created by the oceanic ridge helps the plates to move away from the ridge area
c) Ridge push or gravitational force helps mid oceanic ridge to go upwards or elevate
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d) All of these
APPENDIX 2
Links for further reading
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In the next slide, provide some reference
reading material for the users.
It could be books, reference publications, or
website URLs.
APPENDIX 2
Links for further reading
1. http://lithosphere.gsapubs.org/
2. http://www.platetectonics.com/book/page_12.asp
3. http://www.iris.edu/hq/programs/education_and_outreach/animations/11
4. http://yourweatherblog.com/2011/02/
APPENDIX 3
Summary
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Please provide points to remember to understand the
concept/ key terms of the animation, in the next
slide.
The summary will help the user in the quick review of
the concept.
APPENDIX 3
Summary
At the mid-oceanic ridge, new plates pushes the older oceanic plate. The oceanic plate dives under the
continental plate and scraps against the continental plate forming the accretionary wedge. The subducting
plate continues to go below the over-riding plate, and the convection currents pulls the slab. Due to high
friction between the plates, the continental plate buckles up. The accretionary prism continue to rise and
forms a fore arc basin. Partial melting of subducting plate provides the molten material for magmatic arc and
for spreading axis of the back arc basin.