Conservation of Natural Resources Module-3.pptx

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1. Module-3

2. GEOLOGY Geology is the science of the earth GEO =Earth, LOGY =Study of science It deal with the study of Origin , age, interior structure, and history of earth E v olutio n and modif i c a tion o f v arious sur f ace f e a t u r es like rivers , mountains and Lakes . Material make ups the earth.

3. Application of Earth Science in Civil Engineering Practices Mapping Exploration Project Planning Surface water Groundwater Geological Structures Tunneling Earthquake

4. Main and Allied Branch of Geology Main Branch Allied Branch Physical Geology Engineering Geology Mineralogy Mining Geology Petrology Geophysics Structural Geology Geohydrology Historical Geology Geochemistry Palaeontology Economic Geology

5. Mineralogy This deals with the study of minerals. Mineralogy deals with the detailed mode of formation, composition, occurrence, types, association properties uses etc .

6. Mineralogy Civil Engineering point of view The strength and durability of the material depends on chemical composition . The quartzite and marble resemble one another in shine colour and appearance but quartzite by virtue of its mineral composition is very hard tough, strong and durable while the marble disintegrates and decompositio n in a short period because of its mineral composition and properties.

7. P et r ology Petro = Rock , Logos = Study. Petrology deals with study of Rocks . The e a r t h cr u st is als o called a s lithos p he r e , is mad e of ty p es o f r oc k s . P e t r ol o g y de al s wi t h t h e structu r e, t e x t u r e , comp o si t i o n , occur r enc e , different f o rm a t i on, types etc.

8. P et r ology

9. P et r ology Civil Engineering point of view The co m p osit i on an d t e x t u r e c h a r ac t erist i cs o f r oc k s primarily contribute to their strength and durability . Rocks based on their suitability can be used for foundation for dams , tunnelling's and other construction material s. Hence it is m o st imp o rt a n t b r a nc h o f G eology f r om c i vil Engineering point of view.

10. Mineralogy Minerals have been defined as naturally occurring substances, mostly inorganic , that are characterized by a definite chemical composition and a definite atomic structure . The branch of geology dealing with the study of minerals is designated as Mineralogy. Each mineral is generally characterized with a set of qualities some of which are always distinctive and differentiate it from other minerals. Some of these qualities or properties may be studied from the body of the minerals, its shape, color, shine, hardness etc.; these are termed physical properties.

11. Properties of Minerals HABIT A mineral may sometimes show a definite and characteristic arrangement in its outer appearance or physical shape . This shape is expressed by the term Habit and is typical in the case of many minerals. Fibrous habit : -When the mineral is made up of fibers, generally separable, e.g. in Asbestos. Columnar habit: - When the mineral is composed of thin or thick columns, sometimes flattened, e.g. in Hornblende. (Apatite)

12. Apatite

13. Bladed habit: - The minerals appears as if composed of thin, blade like structure, e.g. in Kyanite

14. Granular habit: - The mineral shows numerous grains packed together, e.g. in Chromite

15. Tabular habit: - The mineral is flat that are elongated e.g. in Calcite, Orthoclase.

16. COLOUR Minerals show great variety of colors. The color of a substance and its appearance in light depends upon the composition and structure of the substance

17. The  streak  of a mineral is the color of the powder produced when it is dragged across an un-weathered surface. ... The surface across which the mineral is dragged is called a " streak  plate", and is generally made of unglazed porcelain tile.

18. LUSTER The Shining / Reflection of light from the surface of mineral. The luster of minerals varies with the nature of their surface smooth / rough and the quantity of light reflected . The luster of mineral can be divided into two groups. i )Metallic. ii)Non-metallic

19. DIAPHENEITY: Diaphaneity is the ability of the mineral to transmit light through it. The following terms are used to describe the varying degree of transmission of light.

20. FRACTURE: The fracture is the nature of the broken surface of mineral. The breakage of a mineral in a direction other than that of cleavages. Fracture is described according to the breakage pattern, i.e. the appearance of the broken surface. Note: Cleavage  refers to the way some  minerals  break along certain lines of weakness in their structure

21. Even fracture-Appearance of a mineral in its broken surface is Smooth. Mineral examples: Chert , Mica. Uneven fracture- when the mineral breaks with very rough and coarse surfaces. Mineral examples: Chromite and various other minerals. Conchoidal fracture- when a mineral breaks with curved Surfaces or concentric Rings or half moon shape. Mineral example: Quartz

22. Hardness The hardness of a mineral is the resistance it offers to abrasion, which is determined by observing the comparative ease or difficulty in scratching it with another mineral of known hardness. It is always expressed by Moh's Scale of Hardness

23. Specific gravity  is the "heaviness" of a  mineral . It is defined as a number that expresses the ratio between the  weight of a mineral  and the  weight  of an equal volume of water. A mineral possessing heavier and closely spaced atoms will have a high specific gravity: whereas, a mineral possessing lighter and widely-spaced atoms will have a low specific gravity All minerals have been found to possess a specific gravity varying between 1 to 20: but most of them do have specific gravities varying between 2 to 7.

24. CLASSIFICATION OF MINERALS

25. DESCRIPTION OF MINERALS: 1. Quartz Group Form - Granular Colour - (varieties of quartz) Streak - Colourless Luster - Vitreous Cleavage – Absent Fracture – Conchoidal to uneven Hardness – 7 [High] Sp. gr. – Low to Medium. C C - Si 02

26. Occurrence– widely distributed all over India occurs Beach Sand, River sand. Uses: (1) Manufacture of glass, porcelain (2) Flux in metallurgical operation (3) Agates are used as Ornaments (4) Pure quartz crystal shows piezoelectricity (5) Quartz plates are used in controlling frequencies in radio circuits, radar, ultrasonic and multiple telephone lines. (6) Quartz is used in refractories (7) Pure silica is used in ceramics (8) Pure sand, free from impurities is used in manufacturing Sand paper and Abrasive cloth

27. Pink quartz White quartz

28. orthoclase Plagioclase Microcline

29. 3. Mica Group

30. Black and white mica

31. 5. Amphibole Group

32. Types of weathering Physical Weathering Chemical Weathering Biological Weathering Physical weathering , also known as mechanical weathering or disaggregation, is the process class that causes rocks to disintegrate without chemical change. Abrasion (the process by which clasts and other particles are reduced in size) is the primary process in physical weathering. Due to temperature, pressure , frost etc., physical weather may occur. For instance, cracks exploited by physical weathering will increase the surface area that is exposed to chemical action, thereby increasing the rate of disintegration.

33. Where does Physical Weathering occur? In places where there is little soil and few plants grow, such as mountain regions and hot deserts, physical weathering occurs especially. How does Physical Weathering occur? Either by repeated melting and freezing of water (mountains) or by expanding and shrinking the surface layer of rocks baked by the sun (hot deserts).

34. Chemical Weathering Chemical weathering changes rock composition, often transforming them into different chemical reactions when water interacts with minerals. Chemical weathering is a gradual and ongoing process as the rock mineralogy adjusts to the environment near the surface. The rock’s original minerals develop new or secondary minerals . The oxidation and hydrolysis processes are most important in this. Chemical weathering is enhanced by geological agents such as water and oxygen, as well as biological agents such as microbial and plant-root metabolism acids.

35. Where does Chemical Weathering occur? These chemical processes require water and occur faster at higher temperatures, so it is best to have warm, humid climates. The first stage in soil production is chemical weathering (especially hydrolysis and oxidation).

36. How does Chemical Weathering occur? There are various types of chemical weathering, the most important of which is: Solution Removal of rock by acidic rainwater in solution. In particular, dissolved CO2-containing rainwater (this process is sometimes referred to as carbonation) weathers calestone. Hydrolysis Acidic water breakdown of rock producing clay and soluble salts. Oxidation Rock breakdown by oxygen and water, often giving a rusty – colored weathered surface to iron – rich rocks.

37. Biological Weathering Biological weathering is the weakening and subsequent breakdown by plants, animals and microbes of rock. Growing roots of plants can put stress or pressure on rock. Even though the process is physical, a biological process (i.e. growing roots) exerts the pressure. Biological processes can also produce chemical weathering, such as when organic acids are produced by plant roots or microorganisms that help dissolve minerals.

38. Microbial activity breaks down rock minerals by altering the chemical composition of the rock, making it more weather sensitive. One example of microbial activity is lichen ; lichen is a symbiotic relationship between fungi and algae . Fungi release chemical substances that break down rock minerals ; the algae consume the minerals thus released from rock. Holes and gaps continue to develop on the rock as this process continues, exposing the rock to physical and chemical weathering. Burrowing animals can move fragments of rock to the surface, exposing the rock to more intense chemical, physical, and biological processes, thereby indirectly enhancing the weathering process.

39. Fig: Effects of Weathering on Rocks

40. Landforms A  landform  is a natural or artificial feature of the solid surface of the Earth . Landforms together make up a given terrain , and their arrangement in the landscape is known as topography Typical landforms include hills, mountains, valleys as well as shoreline features such as bays and seas including submerged features like volcanoes and ocean basins .

41. Physical characteristics Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, stratification, rock exposure, and soil type. Gross physical features or landforms include intuitive elements such as hills, valleys, river, volcanoes  and numerous other structural and size-scaled (ex. Ponds vs. lakes, hills vs. mountain) elements including various kinds of inland and oceanic water bodies and sub-surface features