Laboratory 6 : Thin Section and Petrography

UNIVERSITI TEKNOLOGI MARAFAKULTI KEJURUTERAAN KIMIAGEOLOGY AND DRILLING LABORATORY(CGE 558)

NAME : MATRIC NOJESSICA ELIZABETH PETRUS 2012273578HUSNI BINTI HASLI 2012640312MAZ EFFTEEKAF BIN HASBULLAH 2012694698MOHAMAD FAHMI BIN SUKIONO 2012413566MOHAMAD HAKIM BIN ITHNIN 2012297034MOHAMAD SYAFIQ HAFIZI BIN AB SHUKOR2012871162 EXPERIMENT: EXPERIMENT 6 THIN SECTION AND PETROGRAPHYDATE PERFORM: 11TH October 2013SEMESTER: 3PROGRAM: OIL AND GAS ENGINEERINGGROUP: EH2233ANOTITLEALLOCATED MARKS %MARKS

1ABSTRACT/ SUMMARY5

2INTRODUCTION5

3AIMS/ OBJECTIVES5

4THEORY5

5APPARATUS5

6PROCEDURES10

7RESULT10

8CALCULATIONS10

9DISCUSSIONS20

10CONCLUSIONS10

11RECOMMENDATIONS5

12REFERENCES5

13APPENDICES5

TOTAL

Remarks:

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TABLE OF CONTENTNO.CONTENTSPAGE NUMBER

1.TABLE OF CONTENTS2

2.SUMMARY3

3.INTRODUCTION4

4.OBJECTIVES5

5.THEORY5

6.PROCEDURES7

7.APPARATUS7

8.RESULTS8

9DISCUSSIONS12

10.CONCLUSIONS13

11.RECOMMENDATION14

12.REFERENCES15

13.APPENDICES16

ABSTRACTIn order to identify minerals in rocks and determining its volumetric percentages and describing their texture, the best method we can use is thin section method.

We have conduct the experiment to identify our rock sample thin in order to know their characteristics such as cleavage, colour, reflectance, shape, and many more. Firstly, we need to make our rock sample to become rock slides, so we use cutting machine to cut the rock samples about 30mm of sample. Then, we are polishing the rock sample by using sand paper before we cement it with hot thermoplastic on the slide. The rock slides then being grind about 30m to make the rock slide thickness become very thin. We use polarize light microscope to examine the thin section of our rock sample. This can be due to know the hidden behind the sample. We can find the characteristic of the rock sample easily since the rock samples are transparent.

INTRODUCTION

Thin sections facilitate microscopic study under bright field or polarized transmitted light to determine the composition, textural and/or structural relationship of minerals in rock, unlithified sediment, sediment or concrete cores, archaeological material and ceramics. Samples, if unlithified, are dried, impregnated with resin and then processed into thin sections for the client. Petrography is a branch of petrology that focuses on detailed descriptions of rocks. Someone who studies petrography is called a petrographer. The mineral content and the textural relationships within the rock are described in detail. Petrographic descriptions start with the field notes at the outcrop and include megascopic description of hand specimens. However, the most important tool for the petrographer is the petrographic microscope The detailed analysis of minerals by optical mineralogy in thin section and the micro-texture and structure are critical to understanding the origin of the rock. Electron microprobe analysis of individual grains as well as whole rock chemical analysis by atomic absorption or X-ray fluorescence is used in a modern petrographic lab. Individual mineral grains from a rock sample may also be analyzed by X-ray diffraction when optical means are insufficient. Analysis of microscopic fluid inclusions within mineral grains with a heating stage on a petrographic microscope provides clues to the temperature and pressure conditions existent during the mineral formation.

OBJECTIVE

- To study the rocks and minerals under microscope. Rocks were cut in cross section before microscopic study.

THEORY

The study of rock minerals and textures is called petrography. Thin section petrography is the study of microscopic features using a "polarizing" or "petrographic" microscope.Thin sections are made from small slabs of a rock sample glued to a glass slide (~1 inch by 2 inches), and then ground to a specified thickness of 0.03mm (30 microns). At this thickness most minerals become more or less transparent and can then be studied by a microscope using transmitted light. Thin sections are time consuming and costly to prepare.Thin sections are viewed using a petrographic microscope under two different lighting conditions- plain polarized light and crossed polarizers.Plane polarized light is light that is constrained to a single plane. The light wave is a simple sine wave that has the vibration direction lying in the plane of polarization.When viewing under plane polarized light, a single polarizer is used. Inserting the upper polarizer is referred to as crossed polarizers, the name given because the two polarizing lenses are set at right angles to each other.

APPARATUS AND MATERIAL

-Apparatus: Thinning section lapping machine Sectioning machine Transmitted polarized light microscope Slide

-Materials: Two different types of rock sample Thermoplastic cement Sand paper

PROCEDURES1. Two samples of rock were prepared which are Sample 1 and 2. Sample 1 was cut with the thickness of 3mm by using rock cutting machine.2. The power supply and light of the machine were switched on.The hood was opened.The sample was clamped firmly in the clamping device.3. Before cutting, the path of the flange was checked. If the black knob and the screw pin could touch the flange, re-position the vise assembly.Then, the hood was closed.4. Pump was turned on. Then, the start button was pressed.5. The cut-off wheel was taken slowly towards the sample.The stop button was pressed and then the hood was opened. The sample was collected and all the ward from the cutting area were cleaned.6. The pump and the light were turned off. The power supply was switched off as well.7. Then, the sample was polished by using sandpaper and was put on a glass slide by using thermoplastic cement in the fume hood.8. The rock sample was thinned for 30 m by using thin section lapping machine and was polished again using the sandpaper.9. After that the sample was observed with a transmitted polarized light microscope for 4x, 10x, 20x and 40x magnification to identify the type of rocks, minerals and ores. All the data were recorded.10. Step 2-9 were repeated for sample 2.RESULT

SAMPLE SLIDE 1Magnified 4x

Magnified 10x

Magnified 20x

Magnified 40x

Rock sample 2Magnified 4x

Magnified 10x

Magnified 20x

Magnified 40x

DISCUSSION

Referring back to the objectives of the experiment, it is to study the rocks and minerals using a microscope. Cross sections are useful for the identification of rocks, minerals and ores. There are two types of specimens prepared for petrographic analysis, thin sections and polished bulk specimens. In this lab thin section being use as for the analysis of rocks and minerals. Thin section will be observed with a transmitted polarized light microscope. From both of samples, we can see that the rock was filled some fluids. As we can see from sample 1 under 10x magnification, the rock may contain vanadinite due to color of sample. From sample 2 under 10x magnification, the rock possibly contains Celestine (grey crystals) and galena (glints of metal). Other than that, cement may also exist in both samples. However, there were still unexpected result where we cant see the clearly structure of the rocks. This will affect the result. Therefore, our expectation may opposite to the actual result. To overcome this situation may be expertise should be provided to help us during conducting the experiment.

CONCLUSION

The objective of this experiment is to study the rocks and minerals closely under microscope. In order to observing the rocks under the microscope, the rocks were cut into thin sections to enable it to be observed under a transmitted polarized light microscope. Based on the observation and study, sample rock 1 contains vanadinite while sample rock 2 contains Celestine. Both samples contain a few fluid and cement. However, an exact identification of types for both samples failed to be established due to poor image quality.

RECOMMENDATIONS

1. Use the proper lab cloth to handling the device.

2. Make sure the sample was polished by using sandpaper before put it on the glass slide to avoid bubble.

3. Make sure the sample was clamped firmly in the clamping device to avoid it from move.

1.

REFERENCES

Internet 1. http://en.wikipedia.org/wiki/Sedimentary_rock2. http://facweb.bhc.edu/academics/science/harwoodr/geol101/Labs/Sediment/index.htm3. http://academic.brooklyn.cuny.edu/geology/leveson/core/topics/rocks/rock_comp_sedimentary2.html4. http://www.uwgb.edu/DUTCHS/EARTHSC102NOTES/102ROCKS.HTM5. http://library.thinkquest.org/J002289/sed.htmlBook1. Element of Petroleum Geology, Richard C.Selley, Second Editon.2. Igneous Rocks Composition, Texture and Classification, Description and Occurence.

APPENDICES

Thin Sectioning Equipment

Geological Cutter

Transmitted Polarized Light Microscope, connected to a computer for image viewing.

Sample 1 (above) and Sample 2 (below).Page | 16