ID template 4.7.1

Created by OSCAR team

October 2011

WelcomeThis 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'5

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Sheath folds

Sheath folds are characteristic features of ductile shear zones. These folds are of strongly non-cylindrical nature. In extreme cases, the folds resemble flattened test tubes.

Related LOs:

– Prior Viewing: graduation level of fundamental of structural Geology

– Future Viewing:

Course Name: Level(UG/PG): PG

Author(s) :Arpita Roy

Mentor(s):Prof. Soumyajit Mukherjee

*The contents in this file are licensed under Creative Commons Attribution-NonCommercial-ShareAlike 2.5 India license

Learning objectives

After interacting with this Learning Object, the learner will be able to

describe the terms related to sheath folds

describe how sheath folds form

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Master layout or diagram • 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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Master Layout

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Increasing shear develops sheath folds

Planner surface

Applied simple shear

Irregularity

Movement of the irregular surface due to simple shear

Shear stress direction

Wrinkled

More wrinkled

More wrinkled

Non cylindrical fold

2D sketch

3D sketch

Fig. a

Fig. b

Fig. c

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Definitions and Keywords

Simple shear: “It is type of constant volume plane strain deformation. There is

no stretching or shortening of lines or the movement of the particles in the third

direction” Fossen (2010)

Ductile shear: A shear without any disruption or breakage

Noncyllindrical fold: Fold with curved hinge line

Refolding: A fold that got folded once again

Fault: Relative movements between the two blocks

Single phase of deformation: Deformation involves in a single phase

Polyphase deformation: Deformation involves in more than one phase

Foliation: Foliation is term used to describe the planner feature in rocks

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Stepwise description of processThe 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

The animator will have to re-draw / re-create the drawings

Add more slides as per the requirement of the animation5

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Description of the action Audio Narration Text to be displayed

Take 4 or 5 lines (as in Fig. 1) and apply shear over them. (Shear is shown by the half arrows in Fig. 1). The result would be shown in Figs. 2, 3, 4. The straight lines will be little bit wrinkled

Description of the action

Audio Narration Text to be displayed

1) Due to pronounced shear force applied on the layers, the layers will be continue wrinkling and finally form a folded pattern. These folds are termed as sheath folds ( Figs. 5 & 6).

2) Time duration for each Fig. will be 2 sec.

The straight lines were little bit wrinkled previously (as in Figs. 2, 3). After suffering shear stress these will become more wrinkled (as in Figs. 3, 4) and finally become folded. (as in Figs. 5, 6).

Shear

wrinkled

More wrinkled

Smaller folds

Noncyllindrical fold

Stepwise description: Two dimensional sketch-Formation of Sheath fold `

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

For Figs. 5 & 6

For Figs. 1, 2, 3, 4

Description of the action

Audio Narration Text to be displayed

1) There is an irregularity on the planner surface. After applying shear stress (as shown by the half arrow in Fig. a), the irregular surface moves towards the frontal side (Fig. b) and further due to pronounced forcing the frontal part moves again (Fig. c) and forms a non -cylindrical fold.

2) Time duration for each step will be 2 sec.

The straight lines will be folded due to shear stress applied on the straight lines and finally forms a non-cylindrical fold

Fig. a

Fig. b

Fig. c

Planner surface

Irregularity

Applied simple shear

Applied simple shear

Due to simple shear the irregular part has moved towards frontal side

Noncyllindrical fold

Stepwise description: Formation of Sheath fold in three dimensions`

Animation design• 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.

• 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.

Slide 3

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Time duration would be for each Fig. 2 sec.Credits

Interactivityarea

Tab 02 Tab 03 Tab 04 Tab 05 Tab 06 Tab 07

Button 01

Button 02

Button 03

Introduction

Slide 3

Sheath fold formation-Alternate type or 2-d

Shearing stress

Little bit wrinkled line

More wrinkled

Smaller fold

Comparatively larger Noncyllindrical fold

Time duration would be for each Fig. 2 sec.

Credits

Interactivityarea

Tab 02 Tab 03 Tab 04 Tab 05 Tab 06 Tab 07

Button 01

Button 02

Button 03

Introduction

Slide 3

Fig. 1

Fig. 2

Fig. 3

Irregularity

Irregularity has moved up due to shear stress

Sheath fold formation-3D sketch

Self- Assessment Questionnaire for Learners

• Please provide a set of questions that a user can answer

based on the LO. They can be of the following types:

– 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).

– 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.

– One can include questions, for which the user will need

to interact with the LO (with certain parameters) in

order to answer it.

– It is better to avoid questions based purely on recall.

APPENDIX 1

Questionnaire

1) Which type of deformation is related with the sheath fold formation?

• Sheath fold is associated with polydeformational event

Sheath fold is associated with different stages in a single phase of deformational event

• It is just associated with folding

• None of these

2) What type of structures are associated with sheath fold formation?

• Folding

Refolding

• Faulting

• None of these

Questionnaire

3) Sheath fold involves

Foliation is parallel to the flow plane

• Foliation has a cross cutting relationship with the flow plane

• Foliation has an angular relationship with the flow plane

• None of these

[You can follow two dimensional sketch- Formation of sheath fold]

Links for further reading

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

APPENDIX 2

1) Fossen H., 2010. Structural Geology.

Cambridge University Press, Cambridge. pp.

237

2) Passchier C.W., Myers J.S., Kroner A., 1991.

Geology of High Grade Terrains. Narosa

Publishing House, New Delhi, India. pp. 70

Summary

• 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

Sheath folds are associated with shear stress. It is a very simple phenomenon. Take a planner surface with an irregularity over it. If you apply simple shear, the irregularity moves frontal side (as shown in three dimensional formation of sheath fold) and after suffering shear stress several times it will form a noncyllindrical folds termed as sheath fold.