Lecture 31

Namaskar. So, yesterday we talked about strike and dip in the lecture. And I also told that in the field, we do not get to see the complete structure, because if it is on a very large scale, then it becomes difficult. But basically it happens because of erosion. But if we get inclined beds and we see its depth, then on the basis of that, we can take this information that is it anticline or sincline. You will be more clear about anticline and sincline which we will talk about in the next slides. And one more important thing I told you that you have to keep in mind that if we move in the dip direction and we have inclined beds, then we will move towards younger beds. But if we move in the opposite to dip direction, then we will encounter older rocks in the field. So, these were the things that we talked about and we were also talking about true dip to some extent. Let us see what is the concept of true dip. And if we know the depth of any bed or strata, then on the basis of that, we can even calculate the depth. We will also talk about that. So, this is an exposure of the field. So, if you look at it carefully, then all these beds are dipping in this direction. So, your direction will be like this. But this face is also exposed. That means we have this face and we have this face. So, in the field, we will also talk about these things in the next slide. So, this will be clear. In the field, we cannot always measure true dip. And what is true dip? It is the perpendicular of our strike. That means if this is our strike, then whatever measurement we have taken exactly perpendicular to the strike, then that will be our dip. But we call this true dip. And this will be our strike. So, as I said in the last lecture, it is not necessary that we are always measuring true dip. We measure our dip on the basis of the exposure that we are getting in any direction. So, we have to keep these things in mind. So, there is an exercise that we will do at the end, after this lecture. That is what we call stereographic projections. So, they can be done manually. But today's softwares are also available. So, you can easily do it on the software if you have the data of strike and dip of the field. So, often we say that whatever you will measure, so here this dip direction is your dip, means you are dipping this way and this is your strike. So, like this is the close-up of this portion, which I was saying that which phase we are looking at, that is very important. So, if we have dip directions, which are taken from the same exposure, then it is difficult for us to identify true dip. We can also do this exercise, that if we have any apparent dips and from that apparent dip, we can also find out true dip. We can do this calculation on the basis of projection, which is called stereographic projection. So, this is a stereographic projection. So, this is a stereographic projection. So, this is a stereographic projection. So, this is a stereographic projection. So, this is a the depth, basically the amount of depth, that inclination tells you, so here you see, all these beds are almost near about vertical, and this is the sequence of sandstone shale here, this is the area near Nainital, so this one is also almost vertical, so if we want to see the depth, we have this perpendicular surface, and this is your depth bed, so this angle will be your depth angle, so we usually measure these things in the field, so as it is shown here, we mostly use compass, so we can measure the depth also, we can measure the height also, we can measure the strike also, so we mostly take these readings in more than one location, so that we can get the overall idea, that what kind of structure it is, whether it is anticline or sincline, which we will talk about later, what is plunging anticline, we will be able to know that also by doing this, so inclination is more important here, because it will decide that this area, either it will be able to slip on the material slope or not, or on the basis of its strength, that is, if the material is very loose and the angle is high, then it is necessary to slip it, so this is an exposure, this is also in the way of Nainital, when you go from the footwell to Nainital, then this exposure is very good, which shows, these are mainly shivaliks, shivalik rocks, so this is inclined and it is very weathered, so some exposures are of this, you can see here, there are some more, which we call it terraces, about river terraces, these are all river deposits, which you can see, these are all river deposits, present day river bank, river is this one, this is the one which is flowing, this is a tributary of Gola river, we were working on that. Now, if we come to true dip and apparent dip, so true dip is, what we have talked about, that if it is almost perpendicular, then we consider it as the true dip, perpendicular to the strike actually. So, true dip is the to the strike of that bed okay, so if this is your bed, so if you have taken the measurement on its right angle, then that will be true dip. But if you have taken the measurement in any other direction other than the true dip direction, true dip is perpendicular, so if you do that, then that will become your apparent dip. So, as we say that this is your horizontal plane, this is your strike and this angle will be perpendicular, so this will become your apparent dip and this will become your true dip. So, if you have taken the measurement on its right angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its right angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its right angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its right angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its right angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your true dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. So, if you have taken the measurement on its left angle, then that will become your apparent dip. And also the arrangement of this rock, rock layers, okay. .