preview

Summary Of Tournemire Exhale

Decent Essays

The first thing that you need to know about the article “Elastic wave velocity evolution of shales deformed under uppermost crustal conditions” is that the tests that were ran were triaxial tests on a series of sample Tournemire shale. A triaxial test is tests the strength of a rock, and that is was the goal of the experiment, to find the strength of the Tournemire shales. This is so important to see the way erosion has effect these shales when they are all in the same area, but they have different orientation bedding. The orientation bedding is anywhere from 0 degrees to 90 degrees, think of 0 degrees as shale that is lying parallel with the ground, while 90 degrees is the other extreme when the shale is perpendicular to the group, both are …show more content…

This will show if there is a major difference between different bedding with how strong the shale is, or, in other words, how eroded it. The pressures that were used during this experiment were 2.5 to 85 MPa, and at strain rates of 3 x 10-7 s-1 to 3 x 10-5 s-1. All these are saying is that there was a variation of pressions and compressions that were put on the shales in order to find when they begin to give and break apart or deform. Another major part of the experiment was that P and S wave elastic velocities were continuously measured with the different orientations with the respect of the bedding and what the maximum compression stress the shale could handle, this is the triaxial portion of the experiment I explained earlier. The reason that the scientists implemented the measurement of the P and S elastic velocities is because it allowed them to really pinpoint the presence of the plastic mechanisms, like mineral reorientation during the deformation of shale. This idea highlighted the fact that some shale has changed (reoriented) and this makes it …show more content…

Anisotropy is the idea that the rocks properties vary with direction, so it is very important in which way that the rock was oriented compared to the load, or the compression, that is applied to the rock. This means that orientation of the bedding that varied between 0 degrees and 90 degrees was very important. The scientists used Thomsen’s parameters to quantify the elastic anisotropy. A few ways that the scientist recognized this was that when brittle shale was preceded by a change in the P wave anisotropy. This was because of the crack growth and mineral reorientation that was discussed earlier. Next, anisotropy variations were the largest for the shale that was deformed perpendicular to the bedding, so when the bedding angle was closer to 90 degrees. When the confining pressures were at the highest, the anisotropy variations were the largest, which makes a lot of sense when we know that the anisotropy is the idea that the properties of rocks vary with different orientation and it created anisotropy reversal at high confining pressures. The last information the scientists found was that the P wave anisotropy change was weak when the shale deformed parallel to the bedding, and this is because it could not take a lot of pressure because of the way it was

Get Access