A final lab exercise that uses the optical mineralogy skills learned in the previous labs and begins the transition to petrographic analysis of thin sections. These tables provide a concise summary of the properties of a range of common minerals. Guide to thin section microscopy extinction raith, raase, reinhardt january 2011 figure 4. Atlas of igneous rocks and their textures a companion volume to the atlas of rockforming minerals in thin section, this fullcolour handbook is designed to be used as a laboratory manual both by elementary students of earth sciences undertaking a study of igneous rocks in thin section under the microscope, and by more advanced students and teachers as a reference work. Now that you are familiar with how to use a petrographic microscope and some of the optical characteristics that can be observed for minerals, it is possible to identify minerals under the polarizing light microscope or at least to eliminate some possibilities.
Identification tables for common minerals in thin section. All the sections thin enough that you can observe under the microscope with transmitted light passing through section, from below they all thin enough that you can see light through them. A colour atlas crc press book this concise, clear and handysized volume, aimed at the undergraduate level, provides an introduction to the observation, description and identifi cation in thin section, using the polarizing microscope, of samples of the commonlyoccurring rocks and minerals. Remember that all of the igneous minerals can also occur in metamorphic rocks. This is a fantastic book for learning about rocks and minerals in thin section. This is a growing collection now over videos highlighting close to 270 samples of short 30s each videos showing a variety of both common and rare minerals in thin section through 360 rotations. This is a preparatory exercise for following labs that will require you to identify. Objectives university of nairobi personal websites. Microscope slides allow you to view rock samples and their mineralogical. Each member of the group should conduct a 200point count of. Rocks and minerals in thin section a colour atlas taylor. Examine thin sections metamorphic 1, metamorphic 2, and metamorphic 3, and handsamples metamorphic a and metamorphic b. Within the tables, minerals are arranged by colour so as to help with identification.
A color atlas of rocks and minerals in thin section edited by w. Nice guide to mineral identification using the petrographic microscope with lots of colour images. Thin section of rocks and minerals specimens slides. This collection contains 20 types of thin section of minerals slides types which is very helpful for age of 15 years and above. The lower second order blue birefringence can be seen in the long sections. Introduction in this laboratory we will investigate the optical properties of the common minerals found in metamorphic rocks. Structured in the form of a dichotomous key, comparable to those widely used in botany, the mineral key provides an efficient and systematic approach to identifying rockforming minerals in thinsection. Interpret metamorphic processes from evidence obtained in hand sample, thin section, and analytical data mineral composition, interpret tectonic setting of metamorphic belt, andcritically evaluate the literature regarding metamorphic principles, observations, to gain a better understanding of the earth system.
Not only are fluid components necessary to form any hydrous or carbonate minerals, but the fluid phase can act as a catalyst for metamorphic reactions. The identification of minerals, either in rock thin sections or individual mineral grains. Minerals are listed in the order in which they appear in. Within the tables, minerals are arranged by colour so as tohelp with identification. In this activity, you will look at some diagrams of thin sections. Presented rocks are mainly magmatic and metamorphic with some. Read chapter 1 of an introduction to metamorphic petrology by bruce yardley or chapters 2223 of igneous and metamorphic petrology by john winter or chapter 16 of igneous and metamorphic petrology by philpotts. The only way you can become proficient at identifying minerals in thin section is to look down the microscope and make.
In some cases, porphyroblasts overgrow the foliation present at the time of growth, preserving it. Excellent for collectors, microscopy enthusiasts and educational bodies. Classifying metamorphic rocks examine thinsections metamorphic 1, metamorphic 2, and metamorphic 3. Pdf a key for identification of rock forming minerals in. Aug 15, 2016 this is a fantastic book for learning about rocks and minerals in thin section. Identification tables for common minerals in thin section these tables provide a concise summary of the properties of a range of common minerals. Reaction textures in granulites and hp to uhpmetamorphic rocks. Nov 02, 2017 this concise, clear and handysized volume, aimed at the undergraduate level, provides an introduction to the observation, description and identifi cation in thin section, using the polarizing microscope, of samples of the commonlyoccurring rocks and minerals. A last look at igneous minerals in thin section dexter perkins, univ. You will study minerals found in rocks and identify rocks containing such minerals.
Low grade metamorphism an overview sciencedirect topics. This is a somewhat haphazard collection of metamorphic textures and rocks seen in thin section, with some discussion of the processes thought to have made them. John faithfull 1998 identification tables for common minerals in thin section these tables provide a concise summary of the properties of a range of common minerals. If a mineral commonly has a range of colours, it will appear once for each colour. Process of mineralogical and structural textural changes of rocks in the. The slate contains a higher proportion of uncrystallized clay minerals, and instead of schistosity shows sheet or thin horizontal lamination, unlike argillite. Metamorphic rocks in thin section contents image scales widest frame width alsilicates other aluminous minerals amphiboles pyroxenes sheet silicates other metamorphic minerals 20x 6 mm 40x 3 mm 100x 1 mm 200x 0. This granulite facies schist has coarse sillimanite prisms that can be seen in long section and in their diamondshaped cross sections. Foliations develop and change as a result of rock deformation. Such foliation relics can be helpful in the reconstruction of deformation history. Addition and subtraction can be easily recognised by observing the changes in the colour sequence along. These dark colored minerals tend to become segregated into distinct bands through the rock this process is called metamorphic differentiation, giving the rock a gneissic banding.
Process of mineralogical and structural textural changes of rocks in the solid state in response to physical and chemical conditions which differ. Metamorphic mineral key pdf version metamorphism produces some common, well known minerals, as well as ones only a geologist would recognize. Sometimes there are three photomicrographs to present plane, crossed and stageobjective raisedlowered. Sillimanite prisms in a biotitegarnetcordierite schist. Those shown here are either rare or absent in igneous rocks, the minerals look. Pdf microphotographs of minerals and selected rocks in thin section. All images have two views, in plane and crosspolarized light. Students look at some of the same minerals and others in thin section. Phase equilibria in metamorphic thin sections problem 1 each student will be assigned to a group and each group will be assigned a thin section of a regional metamorphic rock. Metamorphic rocks 2 types of textures foliated and nonfoliated foliated banded rock, minerals are arranged in bands, or thin sheetslayers nonfoliated unbanded rock, usually consist of all one type of mineral so may appear to have a granular or. These can range from textures similar to the original protolith at low grades of metamorphism, to textures that are purely produced during metamorphism and leave the rock with little resemblance to the original protolith. It presents gradation in degree of metamorphism ranging between slate and mica schist.
Conclusion has to be that minerals somehow reorient the planes in which light is vibrating. Metamorphic rocks orientation of minerals or schistosity is the significant feature of schist of lowgrade metamorphism, and their slips and stick form is the basic feature of lepidoblastic and nematoblastic structure. Many of the images have two views, most showing paired plane and crosspolarized light images. But, each mineral typically has something important to say about the rock. Minerals in thin section is the perfect supplement for mineralogy, optical mineralogy, and petrography courses. In thin section, cryptocrystalline quartz and muscovite show. These are photomicrographs very thin slices of rock, seen in planepolarised light, or between crossed polarisers, when the colours seen are produced by interference of light. A thin section is made by grinding down a slice of rock which has been glued to a. Examine thinsections metamorphic 1, metamorphic 2, and metamorphic 3, and handsamples metamorphic a and metamorphic b. Identification tables for common minerals in thin section john faithful, hunterian museum, university of glasgow.
It is possible to study and understand metamorphic rocks with knowing these minerals. Philpotts 2003 petrography of igneous and metamorphic rocks. Summarize the progression of different rock types produced by regional metamorphism. As we discussed previously, the fluid phase plays an important role in metamorphic reactions. Structured in the form of a dichotomous key, comparable to those widely used in botany, the mineral key provides an efficient and systematic approach to identifying rockforming minerals in thin section. Metamorphic rocks thin sections microscopy and minerals. Animated pdfs showing optical properties of minerals john brady. Brodie this concise, clear and handysized volume, aimed at the undergraduate level, provides an introduction to the observation, description and identifi cation in thin section, using the polarizing microscope, of samples of the. Illustrate the time relations between metamorphic minerals and deformation. If a mineral commonly has a range of colours, it will appear once for each.
Metamorphic minerals grow as a result of the progress of chemical reactions at different pt conditions. Metamorphic minerals in thin section union college. Atlas of metamorphic minerals university of oxford. Metamorphic minerals and textures in thin sections. Kendall this elegant book fits nicely in ones hand and is beautifully reproduced. Pdf the splendor of rocks and minerals in thin sections. For thin section examination, we have used the guide to compositional categories and their grade indicators given by fry 1984, pp. All the sections thin enough that you can observe under the microscope with transmitted light passing through section, from below they all. Geological microscope thin sections of igneous, metamorphic and sedimentary rock specimens, made from our very own stock which we collect from the field our selves, the slides are 30 microns thick, 46 x 27 mm and come with a cover slip and sleeve. Taking pictures with your cell phone camera and then trying to match them with pictures on the web is not a successful strategy. Anhydrite grain showing a colour sequence covering seven orders.
The only way you can become proficient at identifying minerals in thin section is to look down the microscope and make observations. Rockforming minerals of metamorphic rocks, in thin section a work in progress atlas of metamorphic minerals. The texture is platy because it contains mi nerals like mica. Rocks and minerals in thin section, second edition. Document the minerals present in each of the slides, and using this data and the table below, determine to which rock type, and metamorphic facies these rocks belong. The metamorphic mineral assemblages are represented by epidote, chlorite and actinolite. In this concise, clear and handysized volume, aimed at the introductory undergraduate level, these highly respected and successful authors explain to the reader, with the help of 180 superb colour photomicrographs, how to observe, describe and identify thin section samples of rocks and minerals using the polarizing microscope. It has lots of color photomicrographs, often presented in pairs so the reader can see the thin section in planepolarized and crosspolarized light. Some textures or appearances, like foliation, are unique to metamo rphic rocks.
This concise, clear and handysized volume, aimed at the undergraduate level, provides an introduction to the observation, description and identifi cation in thin section, using the polarizing microscope, of samples of the commonlyoccurring rocks and minerals. Mineralogical society of america mineralogy, petrology. Phyllite is foliated metamorphic rock rich in tiny sheets of sericite mica. Rockforming minerals of metamorphic rocks, in thin section a work in progress. Rockforming minerals of metamorphic rocks, in thin section a work in progress 1 olivine. Interpret metamorphic processes from evidence obtained in hand sample, thin section, and analytical data mineral composition, interpret tectonic setting of metamorphic belt, andcritically evaluate the literature regarding metamorphic principles, observations, to gain a. Igneous rock thin section point counting and iugs classification. For example, sio 2rich fluids can infiltrate ultramafic rocks, which normally have rather little silica, dramatically changing the bulk composition, and stabilizing a new group of high sio 2 minerals. Identification tables for common minerals in thin section sf rocks. Because the dark colored minerals tend to form elongated crystals, rather than sheet like crystals, they still have a preferred orientation with their long directions perpendicular to the maximum differential stress. Microphotographs of minerals and selected rocks in thin section, making using polarizing microscopy with cross and reflected light.
Identification tables for common minerals in thin sectionthese tables provide a concise summary of the properties of a range of common minerals. Metamorphic rocks 2 types of textures foliated and nonfoliated foliated banded rock, minerals are arranged in bands, or thin sheetslayers nonfoliated unbanded rock, usually consist of all one type of mineral so may appear to have a granular or uniform texture ex. Optical mineralogy mickey gunter, university of idaho. Over time, this collection should become more orderly and comprehensive, but dont hold your breath. Some common rock types as seen under the microscope. For thinsection examination, we have used the guide to compositional categories and their grade indicators given by fry 1984, pp. Metamorphic microstructures and textures in thin section. Typical lowgrade metamorphic minerals are albite, muscovite, chlorite, actinolite and talc. Designed for students to have on hand in the laboratory, this manual includes data and photos for all major igneous, metamorphic and sedimentary minerals. In problematic cases the samples have been examined in thin section, which also allows an estimation to be made of the metamorphic grade. Those shown here are either rare or absent in igneous rocks, the minerals look somewhat different because of their metamorphic petrogenesis, or if i just like them.
A colour atlas of rocks and minerals in thin section wiley. Metamorphic rocks thin sections microscopy and minerals images. It is presented a rockforming minerals and accessory with rare. Procedure look at the diagram of rock a on the next page. Relate common metamorphic rocks to different types of metamorphism. Pdf identification tables for common minerals in thin.