Presentation (3).pptx earth science stem 11

It is a presentation about earth sciences that talks about formation of rock and the different types of rock that is founded in our world

1. FORMATION OF ROCKS

2. Setting aside rocks that fall from the sky, such as meteors andfragments of asteroids, the birth of rocks begin from the core of ourplanet. Tracing the birth, formation, and transformation of rocks willtake us to two sets of physical processes. One is a set of endogenicprocesses, and the other, exogenic. The terms suggest what takesplace under these processes.

3. Endogenic processes refer to geologic processes that take place belowthe Earth's surface, the interior of the planet. Exogenic processes referto those that take place on the Earth's surface.

4. We will discuss briefly the types of rocks and how they form. A more detailed discussion about the endogenic and exogenicprocesses that led to their formation will be discussed in the nextchapter, Earth's processes.

5. Rocks are solid aggregate of mineral grains

6. Sedimentary rocks cover Earth's land surface, about 78% of current land surface. But it only constitutes 8% of the entire volume of Earth's crust. The big part which makes the crust comes from igneous and metamorphic rocks.

7. It is quite easy to identify sedimentary rocks from afar. You may have passed by expressways on your field trips, and along the waysaw a distinct layer of rock on the sides of a huge rock outcrop. Youare looking at a layer of sedimentary rocks.

8. Sedimentary rocks are deposited in layers called strata. The entirelayers displayed by a rock outcrop are called bedding. Sedimentaryrocks are sources of natural resources, such as, coal, fossil fuels,drinking water, minerals, etc. They are also a resource for manyconstruction materials and chemical products.

9. Batholiths, also called plutons, are a huge mass of plutonic rocks hundreds of kilometers long and 100 km wide. They form below the Earth's surface. On some occasions, they are discovered lying on the Earth's surface because the soil material that once covered them had eroded.

10. Sills are plutonic rocks that intruded into cracks and crevices of existingrocks. They are generally smaller and are formed horizontally.

11. Dikes are plutonic rocks that intruded into cracks and crevices of existingrocks but they are slanted.

12. Horizontal or slanted layers of distinct rock types sandwichedbetween rocks of a different physical structure are clues suggesting you could be looking at intrusive igneous rocks. Even though they are generally lodged below the Earth's surface, soil erosion occasionally exposes them to the atmosphere.

13. Sedimentary rocks Sedimentary rocks, as the name suggests, are formed by sedimenOther types of rocks, such as igneous and metamorphic rocks, sheoff sediments as a result of physical and chemical weathering. Theare carried away by wind, water, ice, mass movement or glaciers anddeposited into sedimentary basins, usually a body of water, suchponds, lakes, and seas. There at the bottom they accumulate and foma layer of sediments. The skeletal remains of organisms from millionsof years ago also add to the sediments that form sedimentary rocks

14. Pressure from a massive body of water on top compresses thelayer. In the course of millions of years, deposition and cementationturn them into hard solid sedimentary rocks.

15. Metamorphic rocks Metamorphosis is a combination of two Greek wordsmeans after and morphe means shape. Metamorphosis is the dshape. To metamorphose is to change shape. For metamorphic rockthis describes a type of rock that arose from either igneous moor sedimentary rocks. The change took place because of extrepressure and temperature.

16. Rocks do get exposed to variations in pressure and temperatbecause they do not stay where they are. It is difficult to imagthat a huge rock the size of a hill was once underwater or undemEarth's surface. There at the bottom of the oceans or under Earsurface some hundreds of kilometers deep, rocks are exposedextreme pressure and temperature but not to a degree that theyor break apart.

17. Protolith, parent rock or original rock

18. Metamorphic rocks form only 12% of Earth's land surfacetogether with igneous rocks compose 92% of Earth's crust. The raof temperature and pressure in which a protolith transformsmetamorphic rock is 200 °C to 320 °C and 300 MPa to 600 MPa (Mmegapascals).

19. Activity 2.5 QUICK ANSWERS 1. What are the two types of igneous rocks? 2. Name one similarity and one difference between volcanic andbile splutonic rocks? 3. Give two examples each of sedimentary and metamorphicrocks.