1. ID template 4.7.1 Created by OSCAR team October 2011

2. 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' 5 2 1 4 3

3. 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

4. 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 5 3 2 4 1

5. 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…) ‏ 5 3 2 4 1

6. Master Layout 5 3 2 4 1 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 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

7. 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 5 3 2 4 1

8. Stepwise description of process 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 The animator will have to re-draw / re-create the drawings Add more slides as per the requirement of the animation 5 2 1 4 3

9. Description of the actionAudio 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 NarrationText 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

10. Description of the action Audio NarrationText 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 Due to simple shear the irregular part has moved towards frontal side Noncyllindrical fold Stepwise description: Formation of Sheath fold in three dimensions `

11. 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 5 2 1 3 4

12. Time duration would be for each Fig. 2 sec. Credits Interactivity area Tab 02 Tab 03 Tab 04Tab 05Tab 06Tab 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

13. Time duration would be for each Fig. 2 sec. Credits Interactivity area Tab 02 Tab 03 Tab 04Tab 05Tab 06Tab 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

14. 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

15. 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

16. 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]

17. 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

18. 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

19. 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

20. 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.