1. Sedimentary Rocks A Virtual Practical I.G.Kenyon

2. The following slides are all sedimentary rocks From the information displayed Decide if the rock is: clastic, organic or chemical Identify each rock as accurately as possible Suggest a sedimentary environment in which it may have formed

3. Identify this Sedimentary Rock 1 1cm Poorly Sorted 40% Muddy Matrix Rock Fragments Mineral Grains

4. Identify this Sedimentary Rock 2 2cm Reacts with dilute hydrochloric acid Comprises over 70% broken bivalve shells Remainder of rock is silt and iron oxides

5. Identify this Sedimentary Rock 3 2cm Comprises entirely clay minerals and carbonaceous material Well preserved graptolites are found in the rock Splits into thin layers easily (Fissile)

6. Identify this Sedimentary Rock 4 1cm Reacts with dilute hydrochloric acid Comprises entirely of spherical grains 0.5–1.0mm in diameter

7. Identify this Sedimentary Rock 5 1cm Made up entirely of clay minerals such as kaolinite, illite and bentonite Homogenous or massive with no trace of bedding or laminations

8. Identify this Sedimentary Rock 6 4cm Comprises angular fragments 0.5mm – 8cm in diameter All parts of the rock react with dilute hydrochloric acid

9. Identify this Sedimentary Rock 7 Comprises mainly sub angular quartz and feldspar grains 20% of the rock has fragments 2 - 4mm in diameter 5mm

10. Identify this Sedimentary Rock 8 1cm Fibrous appearance Very low density Clearly visible remains of organic matter Rich in carbon

11. Identify this Sedimentary Rock 9 2cm Composed entirely of silica Broken surfaces show conchoidal fracture

12. Identify this Sedimentary Rock 10 Comprises some clay minerals such as kaolinite and illite Has a gritty feel when rubbed on the teeth, >10% quartz present 1cm

13. Identify this Sedimentary Rock 11 Well rounded flint pebbles 8mm – 6cm in diameter Cement does not react with dilute hydrochloric acid

14. Identify this Sedimentary Rock 12 Rich in carbon, makes a black mark on paper No recognisable traces of organic material evident

15. Identify this Sedimentary Rock 13 Comprises almost entirely clay minerals, chiefly kaolinite No bedding or laminations evident. Plastic when wet 1cm Grain size <1/256mm

16. Identify this Sedimentary Rock 14 Comprises well rounded quartz grains 0.25 – 0.5mm in diameter Weak iron oxide cement-crumbles in the fingers (friable) 1cm

17. Identify this Sedimentary Rock 15 Reacts with dilute hydrochloric acid Rock is made up of coccoliths Fossil replaced by flint 2cm

18. Identify this Sedimentary Rock 16 Reacts with dilute hydrochloric acid Made up mainly of broken crinoid stems 1cm

19. Identify this Sedimentary Rock 17 Comprises entirely well rounded quartz grains 0.25–0.75mm in diameter Very well cemented together by silica 1cm

20. Identify this Sedimentary Rock 18 Does not react with dilute hydrochloric acid Has a distinct banded appearance 1cm

21. Identify this Sedimentary Rock 19 1cm Comprises angular to sub angular grains of quartz and feldspar Contains more than 25% feldspar Iron oxide cement

22. Identify this Sedimentary Rock 20 1cm Particle size varies from 1mm – 4cm Comprises fragments of limestone, basalt, slate and quartz All particles are angular Red iron oxide cement

23. Identify this Sedimentary Rock 21 1cm Comprises quartz and muscovite grains Splits readily into slabs 3-6cm thick

24. Identify this Sedimentary Rock 22 Reacts with dilute hydrochloic acid Made up entirely of angular shell fragments 0.5-3mm 1cm

25. Identify this Sedimentary Rock 23 Has a woody ‘ring’ to it when tapped Rich in carbon Low density Organic structure clearly visible 1cm

26. Identify this Sedimentary Rock 24 Made up entirely of hydrated calcium sulphate This variety is called Desert Rose 2cm

27. Identify this Sedimentary Rock 25 Contains some clay minerals, chiefly kaolinite Over 10% quartz present plus mica flakes Feels gritty when rubbed on the teeth Mica flakes concentrated on lamination surfaces 1cm

28. Identify this Sedimentary Rock 26 Jet black colour Contains over 95% carbon Vitreous lustre Marks paper No recognisable traces of any organic matter 1cm

29. Identify this Sedimentary Rock 27 Made up entirely of clay minerals, chiefly kaolinite No obvious laminations or bedding present Contains well preserved trilobite pygydium 2cm

30. Identify this Sedimentary Rock 28 2cm Reacts with dilute hydrochloric acid Has an internal concentric banded structure Specimen obtained from the roof of a limestone cave 2cm

31. Identify this Sedimentary Rock 29 All parts of the rock react with dilute hydrochloric acid Contains spherical grains of calcium carbonate over 2mm in diameter 5mm Spherical grains with internal concentric structure

32. Identify this Sedimentary Rock 30 Composed entirely of sodium chloride Occurs in thin, near horizontal beds Often grey, white colourless, orange or brown Tastes salty 1cm

33. Identify this Sedimentary Rock 31 Composed entirely of silica Breaks with a flat or even fracture Specimen above has been fashioned into a cutting tool 1cm

34. Identify this Sedimentary Rock 32 Comprised of clay minerals and carbonaceous material Lacks distinct laminations Contains well preserved plant fragment 1cm

35. Identify this Sedimentary Rock 33 Comprises mainly quartz grains <0.25 in diameter Brown colour due to 10-15% clay content Contains external moulds and casts of brachiopods 1cm

36. Identify this Sedimentary Rock 34 1cm Contains a high percentage of sub- rounded to rounded quartz grains Some rock fragments Poorly sorted, particle size ranges from <0.5mm – 1cm Finer matrix makes up 15-20% of the rock No reaction with dilute hydrochloric acid

37. Identify this Sedimentary Rock 35 Rich in iron, hence brownish colour (limonite) Cannot be found forming anywhere on earth today 1cm

38. Name this Sedimentary Rock 36 Reacts with dilute hydrochloric acid Contains corals preserved in life position

39. Identify this Sedimentary Rock 37 Reacts with dilute hydrochloric acid Made up of coccoliths 1cm

40. Identify this Sedimentary Rock 38 1cm Particle size 1mm up to 8mm, quite poorly sorted Mineralogy mainly sub-angular to sub-rounded quartz and feldspar

41. Identify this Sedimentary Rock 39 Reacts with dilute hydrochloric acid May contain a small percentage of clay minerals 1cm

42. Identify this Sedimentary Rock 40 1cm Comprises quartz grains 0.25 – 0.75mm in diameter Moderately well cemented by glauconite, a pale green mineral

43. Answers 1. 1. Greywacke 11. Conglomerate 2. Bioclastic Limestone 12. Bituminous Coal 3. Black Shale 13. Clay 4. Oolitic Limestone 14. Desert Sandstone 5. Mudstone 15. Chalk 6. Limestone Breccia 16. Crinoidal Limestone 7. Millstone Grit 17. Orthoquartzite 8. Peat 18. Chalcedony 9. Flint 19. Arkose 10. Siltstone 20. Breccia

44. Answers 2. 21. Micaceous Sandstone 31. Chert 22. Calcareous sandstone 32. Mudstone 23. Lignite(Brown Coal) 33. Fine Sandstone 24. Rock Gypsum 34. Conglomerate 25. Micaceous Siltstone 35. Ironstone 26. Anthracite 36. Coral Limestone 27. Mudstone 37. (Red) Chalk 28. Tufa 38. Grit 29. Pisolitic Limestone 39. Micrite/Marl 30. Rock Salt 40. Orthoquartzite

45. The End