ULTRAMAFIC earth and life science ppt. .

earth and life science ppt. ultramafic rocks

1. ULTRAMAFIC

2. Peridotites and Komatiites Igneous rocks composed of mainly olivine and pyroxene are called peridotites (phaneritic) or komatiites (aphanitic). Utramafic rocks are characterized by the abundance of ferromagnesian minerals and are usually dark green to black in color.

3. Dunites are ultramafic rocks composed of purely >90% olivine while pyroxenites are rocks composed are rocks composed of mostly pyroxenes.

4. Komatiites are the volcanic equivalent of peridotites Rare and restricted to older ages

5. Mafic: Gabbro and Basalt Gabbro is the coarse-grained mafic rocks composed of plagioclase, pyroxene and minor olivine while basalt is the fine-grained version.

6. Intermediate: Diorite and Andesite Diorite is the phaneritic intermediate rock with the distinct salt and pepper appearance. Andesite appears gray in color

7. Intermediate Rocks Define the range where felsic and mafic rocks meet.

8. Felsic: Granite and Rhyolite Granite is a coarse-grained felsic rock composed of quartz, k-feldspars, amphibole, and biotite. Rhyolite is the fine-grained counterpart of granite

9. Sedimentary Rocks: Rocks from sediments The process of breaking down rocks in order to achieve chemical and physical stability is what generates sediments that will later form sedimentary rocks

10. Sedimentary Rocks: Rocks from sediments The process of breaking down rocks in order to achieve chemical and physical stability is what generates sediments that will later form sedimentary rocks

11. Sedimentary Rocks: Rocks from sediments When you encounter the term sediment, the first image that might come into your mind would be the sand you see along the beach.

12. Sedimentary Rocks: Rocks from sediments Sediments are broken down rocks that constitute sedimentary rocks.

13. Sedimentary Processes A small drop of rain, blowing wind, animal grazing or rivers flowing all contribute to the degradation of rocks present on the surface. These processes leading to the breakdown of rocks are what we call sedimentary processes.

14. Sedimentary Processes During the formation of sediments from rocks, a series of sedimentary processes must take place before they are all transformed to sedimentary rocks.

15. Weathering Is the process of breaking down rocks physically of chemically. Chemical weathering – the original minerals are transformed to more stable phases due to difference in the prevalent conditions.

16. Weathering Physical weathering – allow the breakdown of rocks into smaller units.

17. Weathering Chemical weathering processes result to decay of minerals present in rock.

18. Erosion Means to “eat away” Takes place with the help of gravity and medium such as water, wind, organisms

19. Transport The movement of the sediments from one place to another. Agents that eroded the sediments from their source may still be the agents that will transport them

20. Deposition Is the settling of the sediments in an area before they are finally lithified to form sedimentary rocks.

21. Diagenesis Is the group or processes responsible for the transformation of sediments into sedimentary rocks.

22. Classifying Sedimentary rocks 1. Detrital sedimentary rocks define the group of sedimentary rocks that is dominated by the resistant minerals and rock fragments.

23. Classifying Sedimentary rocks Conglomerates and Breccias are detrital sedimentary rocks composed of gravel-sized sediments.

24. Classifying Sedimentary rocks Conglomerates are composed of rounded rock fragments while breccias have angular ones while breccias are angular.

25. Classifying Sedimentary rocks Sandstones are detrital sedimentary rocks composed of sand-sized sediments. Siltstones are composed of slilt -sized

26. Classifying Sedimentary rocks 2.Chemical sedimentary rocks are rocks from the precipitation of solutions rich in mineral components.

27. Carbonate-based CO3 chemical sedimentary rocks The most abundant chemical sedimentary rock is called limestone. It is composed primarily of the mineral calcite

28. Carbonate-based CO3 chemical sedimentary rocks Calcite (CaCO3) is a mineral that readily reacts with dilute hydrochloric acid to form gas bubbles of carbon dioxide

29. Carbonate-based CO3 chemical sedimentary rocks Coquina is a limestone that has shell fragments that are loosely cemented. Chalk is a limestone made from the carbonate shells of microscopic organisms.

30. Carbonate-based CO3 chemical sedimentary rocks Travertine is the limestone you see in caves that look like wafers stacked on top of each other.

31. Silica-based (SiO4) Silica ( e.g ) quartz, just like calcite can easily dissolved in water and precipitate back when the conditions

32. Other chemical sedimentary rocks Minerals aside from quartz and calcite can precipitate from solutions. Halite is most commonly known as rock salt.

33. Other chemical sedimentary rocks Coal is an organic-rich sedimentary rock from mostly plant remains that were deposited as sediments. Coal grade is simply a measure of how much combustible carbon is present in coal.

34. Other chemical sedimentary rocks Peat is the term used for partially modified plant remains. Lignite is still soft with a lot of impurities

35. Metamorphic Rocks: Transformed rocks Metamorphism is the transformation of one rock to a metamorphic rock.

36. What happens during metamorphism? 1. Heat – rocks exposed to an increase in temperature will undergo recrystallization in order to form larger crystals.

37. What happens during metamorphism? 2. Pressure is the amount of force acted on a body over a unit area. Rocks undergoing pressure are subject to deformation in the same way when we compress or stretch some materials.

38. What happens during metamorphism? 3. Chemically-active fluids – water or any other fluid , when under pressure and increased temperature will be able to dissolve minerals.

39. Classifying metamorphic rocks Foliated metamorphic rocks were subjected to differential pressure becomes evident in the rock as alignment of minerals, rock fragments, and structures.

40. Classifying metamorphic rocks Slate is a fine-grained with a distinct planar rock cleavage. - Used as natural tiles and flooring

41. Classifying metamorphic rocks 2. Phyllite fine to medium grained foliated rocks 3. Schist are coarse grained foliated metamorphic rock 4. Gneiss

42. Classifying metamorphic rocks 4. Gneiss