1. Y7 Rocks and the Rock Cycle C7.3

2. Lesson 1 – Igneous rocks Rocks come in various different forms: Igneous Sedimentary Metamorphic

3. Where does the word ‘igneous’ come from? from Latin igneus fiery, from ignis fire (think of ignition – to set fire to) This is because igneous rocks are made from volcanic eruptions which look like fire!

4. Under a microscope… Igneous rocks have interlocking grains – these grains are crystals formed when liquid rock in the centre of the Earth cools

7. GabbroGabbro is made of coarse-grained (5mm or so) interlocking crystals. Its overall colour is dark grey but it often contains glassy or pale-coloured crystals of feldspar as well as dark minerals.

8. GraniteGranite is made of coarse-grained (5mm or so) interlocking crystals. It has more light coloured crystals than dark, usually of white or pink feldspar, glassy quartz, and shiny mica

9. BasaltBasalt is made of fine-grained interlocking crystals (about 1mm in size). It is black or dark grey in colour, and often contains vesicles – bubbles of gas trapped as the lava cooled.

10. Dolerite - extrusive

11. Fast cooling Small crystals Slow cooling Big crystals

13. Consider the two sites; which would have large crystals in the rock formed and which would have smaller ones….why?

14. Lesson 2 – Weathering

15. Weathering PhysicalChemical Biological

16. Physical weathering

17. Frost shattered rock

18. Physical weathering Antarctic rocks – what do you think has weathered them? Sandstone in the desert in Nevada – what do you think has weathered them?

19. Biological weathering

21. Chemical weathering

22. Limestone pavements in Yorkshire (Ravenscar and Malham)

23. Chemical weathering St Bartholomew’s Manhattan

24. Lesson 3 – Erosion and deposition http://www.bbc.co.uk/learningzone/clips/the-river-conwy-erosion-and-deposition/3237.html

25. = the break up of rocks into bits (while the rock stays where it is) WEATHERING = the break up of rocks into bits (while the rock is moving) EROSION

26. Erosion These pebbles are smooth as other rocks have rubbed into them over time and broken off the sharp edges

27. Erosion This river bend has been formed by the water wearing away the rock

28. Erosion The wind has formed this shape of rock

29. Deposition Deposition: Stones are picked up by the water and moved from one place to another Will all rocks move the same amount?

30. Deposition Stones are picked up by the water and moved from one place to another

31. Lesson 4 – Sedimentary Rocks sandstone conglomerate sand pebbles

32. What do they have in common? How do you think they are made?

33. SEDIMENTARY Rocks sand sandstone mud mudstone (shale) shells limestone

36. Under a microscope you can see individual grains ‘glued together’ How is this different in appearance to igneous rocks?

39. Nummulitic limestone. Polarised light micrograph of a thin section of a Nummulitic limestone

42. Layers of Sandstone and Mudstone

43. Sedimentary rock is made from other small rocks, mud, dead animals or sea creatures, sand, all built up over years in layers

44. SEDIMENTARY Rocks DEPOSITION - sediment sinks to the bottom of the sea COMPACTION - sediment squashed by more sediment CEMENTATION -sediment cemented together by minerals from the water

45. FOSSILS they are imprints of the remains of living creatures they are found in sedimentary rocks (creatures remains fall into sediment) they are not found in igneous/metamorphic as the heat/pressure in their formation would destroy the remains

46. Lesson 5 – Metamorphic Rocks sandstonemetaquartzite

47. mudstone (shale) slate / phyllite / schist / gneiss

48. limestonemarble

49. METAMORPHIC Rocks sandstonemudstone (shale)limestone Heat and/or pressure acting on other rocks – changes them (without melting) metaquartzite slate / phyllite / schist / gneiss marble

50. Effect of HEAT

51. Effect of PRESSURE

52. Interlocking grains and then clear layers of crystals in ‘bands’ How is this different and /or similar to igneous and sedimentary rocks?

54. GneissGneiss is made of coarse-grained interlocking crystals. Crystals line up in pale and dark layers to give the rock a banded texture

55. SchistSchist is made of medium-grained interlocking crystals. Its shiny appearance is due to the mineral mica. Crystals line up to give the rock wrinkly layers – this is called foliation.

56. MarbleMarble (metamorphosed limestone) is made of calcium carbonate (fizzes with acid). It has medium- grained Interlocking crystals with no alignment.

57. Lesson 6 – The Rock Cycle

58. Weathering & erosion Deposition & cementation Heat & pressure Melting Cooling & crystallisation