When called upon to introduce geology to laymen, I always begin by emphasizing that astronomy was the first of the scientific disciplines to develop, for a man could gaze at the celestial bodies that were thousands of light years away, and of course geology the last since he could not see what was happening a few cm below the ground he stood on.
GO TO  DIFFERENT TOPICS VIA BOOKMARKS AND LINKS

                                                                                                                 

Go to the bookmarks\Links

          
          

     To Play, Pause or Stop background music, use the control here: 

           

 

   

 
Shear Zone kinematics Picture gallery by M Jessel and P Bons

To see most recent references on shear zones, please click here.

                  

                                      

       

 

AN INTEGRATED SOFTWARE TO MAKE SIX DIFFERENT PLOTS THE SAME OR DIFFERENT DATA FILES UNDER OS WINDOWS 1998\WINDOWS NT ENVIRONMENT

         Soothsayer: In nature's infinite book of secrecy,

                               A little I can read.

                                                        -William Shakespeare, Anthony and Cleopatra Act I Sc II

The author has prepared a Windows 98\NT\ME based 32 environment software to make six different strain determination plots. Initially, the software made separately made for each but later they were all combined to obtain any of the six strain plots. A screenshot is given below to get an idea. The text file of help is given in the table given below.
LOGARITHMIC FLINN DIAGRAM


For plotting the logarithmic Flinn diagram or ln a /ln b of the type used by Ramsay and Wood (1973) to explain the role of dilation accompanying deformation, you press the button with the strain ellipse symbol. You need not give any scaling factor in this and this field at top left corner is actually disabled. Enter the values as in case of the Flinn diagram and finally type in zero in the field 1 after the data entry is over. You may see the means of log a, log b and K and for the number of data sets and may also superimpose Vx and Vz curves on this graph too. You may impart diferent colors to the graph elements. In fact you may evolve a scheme of your own for the uniformity of your plots.


RAMSAY'S PLOT OF 1/a AGAINST 1/b
In this, you begin entering the values of X, Y and Z (no scaling factor to be entered; indeed Ramsay introduced this plot for the very reason of eliminating the scaling factor from Flinn's plot). Superimposed on the graph are curves of equal 1/a.b which is the reciprocal of XZ ratio and has values always lower than those of 1/a and 1/b. The top left and bottom right corners of the graph are the points of uniaxially oblate and uniaxially prolate ellipsoids.

 

 

 FLINN DIAGRAM


For plotting a Flinn diagram, you must first specify a value that could be used to fix the scale of a and b axes. Even if you do not specify this, it is possible to find out by BSearch function such a value from the data you have input. But this facility is not included in this software since the user may want to omit some data from his data bank to give a decent look to the plot, and the extreme shapes could be separately discussed.
After you have input this value in the field at top left, enter the values of X, Y and Z in the three boxes or of 1+e1, 1+e2 and 1+e3(X>=Y=>Z). In case you have data which does not allow measurement of all three axes correctly, you may leave the third field blank and the value of this will be computed assuming volume conserving deformation. 

After entry of each data set, press Plot Now which is a default button and will act on simply pressing Enter or Return key. After the data entry is complete, type zero in the field for X. 

The Plot Now button is now disabled. But a message box pops up to tell you that your graph has been copied to the clipboard. The Show and Plot Means button is now enabled. The mean is plotted in the graph and also given in the text box control which has so long been empty. It is also advised that since the captions and annotation 

s are not copied to the clipboard but only the plotted data and coordinates or other lines, the graph should be captured using a screen capturing program and saved under a valid file format such as a GIF (which can be safely used to upload on the web) and the same program may be used to print it.

 The caption font and its attributes can be changed from the FontPicker OCX control that automatically picks up fonts on your system and lists them. There is also an option for the color changes to be made to the background of the graph, the coordinates, the labels etc. The color palette can be obtained by pressing the Atomiser icon button.

You may press the Plot Vx and Vz Curves button and the curves are instantly plotted in two different colors starting from 45 to 82.5 degrees at an interval of 7.5 degrees. Once plotted, these curves cannot be removed since it may remove some of your data points as well. This option therefore does not exist.

 BURNS AND SPRY TRIANGULAR DIAGRAM

 



Burns and Spry introduced this plot based on the hexagonal diagram of Nadai (see Owen 1974) with the triangle represented by the positive sides of the hexagon. The sides are those of log x/r, log y/r and log z/r where r is given by :

r=[(x/2).(y/2).(z/2)]^0.333

The bisectors of the acute angles of the triangles are the x-invariant, y-invariant and z-invariant directions. The line normal to log y/r side is the one of plane strain. The diagram is particularly suited to show complex swappings between principal strains during the progressive rotationaldeformation. The data to be input is the same as in case of the Flinn diagram or Ramsay's diagram or the logarithmic Flinn diagram. Means can beplotted and seen in the field and fonts and color customizations can be done as in case of the previous two options.

NADAI\HSU\HOSSACK DIAGRAM

This diagram makes use of Lode's parameter and the octahedral unit of Nadai and was first used by Jake Hossack in depicting the deformation variation in the Jotun nappe of Norwejian caledonides using deformed pebbles of Bygdin Conglomerate (1968, Tectonophysics). Hossack later (1978) tried to correct the stratigraphic succession by removal of finite strain sufferd by conglomeratic pebbles. The value of Lode's parameter ranges from 1.0 for uniaxially oblate to -1.0 for uniaxially prolate through 0 for plane strain. The diagram has an advantage over the Flinn Plot in the sense that while Flinn Plot can only give idea about the strain ellipsoid shape but little about the magnitude of strain, this plot by using the Octahedral unit of Nadai can also give idea about the magnitude of finite strain. The Lode's parameter is plotted as points of a sixty degrees arc while the Mean strain as radii of the 60 degrees arc. The data to be input is the same and the program calculates the necessary parameters required and plots them not as points of an arc but in terms of trigonometric functions. The mean is plotted and mean parameters are given in the appropriate field.

 For similar screenshots of Flinn Diagram, Ramsay's Diagram, Nadai diagram you may click at the respective  links. You may obtain this software free from the author but for postage and handling.

 Rf/PHI DIAGRAM OF DUNNET(1969)


The last of the options is the classic Rf/phi technique which was considerably developed by Dunnet (1969). The entire theory is out of scope of the present file. The scaling box is now active and the user may input in this field either XY, YZ or XZ depending on the fact that on which of these planes the measurements of Rf and phi were made. In the three fields, enter the values of X, Y and phi. If you have calculated Rf values, you may enter this in the first field, 1 in second field or you may leave this blank and the value of phi in the third field. You may also specify the orientation of the reference line in the second field below the top left. Your data should be such that Rf value calculated will not exceed 30. After the data entry is over, type zero in field 1, and the plot is over. The limitation of this plot is that the Ri values are predetermined and cannot be changed. The contouring on Rf/phi plot is done in terms of Ri values of 1.5, 2, 2.5, 3 and 3.5. If any Rs calculated exceeds 3.5, you will notice that 2Phi fluctuation is small complete closed curves like the shells of an onion are obtained. However, if the value is less than 3.5, the plot is different with 2phi being 90 degrees for Rs less than a given Ri value.

                 

                 

 

Noddy, The beginning of 'Layers' !

                         

     Please click here to go to the Noddy software introductory demo.

 

Earth, mother of all, hail !
Vasudhaiva kutumbakam ! (The whole world is but one family!)-from sanskrit (Rigveda)