Sedimentary Rocks A Virtual Practical I G Kenyon

Sedimentary Rocks A Virtual Practical I. G. Kenyon

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

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

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

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

Identify this Sedimentary Rock 4 1 cm Reacts with dilute hydrochloric acid Comprises entirely of spherical grains 0. 5– 1. 0 mm in diameter

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

Identify this Sedimentary Rock 6 4 cm Comprises angular fragments 0. 5 mm – 8 cm in diameter All parts of the rock react with dilute hydrochloric acid

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

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

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

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

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

Identify this Sedimentary Rock 12 1 cm Rich in carbon, makes a black mark on paper No recognisable traces of organic material evident

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

Identify this Sedimentary Rock 14 1 cm Comprises well rounded quartz grains 0. 25 – 0. 5 mm in diameter Weak iron oxide cement-crumbles in the fingers (friable)

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

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

Identify this Sedimentary Rock 17 1 cm Comprises entirely well rounded quartz grains 0. 25– 0. 75 mm in diameter Very well cemented together by silica

Identify this Sedimentary Rock 18 1 cm Reacts with dilute hydrochloric acid Comprises angular fragments 0. 5 mm – 5 cm in diameter

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

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

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

Identify this Sedimentary Rock 22 1 cm Reacts with dilute hydrochloic acid Made up entirely of angular shell fragments 0. 5 -3 mm

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

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

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

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

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

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

Identify this Sedimentary Rock 29 Majority of clasts are rounded to well rounded Poorly sorted, grain size varies <1 mm to 10 cm

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

Identify this Sedimentary Rock 31 1 cm All parts of the rock react with dilute hydrochloric acid Comprises shell fragments, faecal pellets and large ooliths

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

Identify this Sedimentary Rock 33 1 cm Comprises mainly quartz grains <0. 25 in diameter Brown colour due to 10 -15% clay content Contains external moulds and casts of brachiopods

Identify this Sedimentary Rock 34 Contains a high percentage of subrounded to rounded quartz grains Some rock fragments Poorly sorted, particle size ranges from <0. 5 mm – 1 cm Finer matrix makes up 15 -20% of the rock No reaction with dilute hydrochloric acid 1 cm

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

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

Identify this Sedimentary Rock 37 Locally known as Haggis Rock 1 cm Sub-angular to sub-rounded particles Mixture of rock fragments and quartz grains 0. 5 mm to 5 mm in diameter Matrix consists of mud and silt and makes up over 20% of the rock

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

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

Identify this Sedimentary Rock 40 1 cm Comprises quartz grains 0. 25 – 0. 75 mm in diameter Moderately well cemented by glauconite, a pale green mineral

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. Limestone Breccia 9. Flint 19. Arkose 10. Siltstone 20. Breccia

Answers 2. 21. Micaceous Sandstone 31. Biochemical Lst. 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. Greywacke 28. Tufa 38. Grit 29. Conglomerate 39. Micrite/Marl 30. Rock Salt 40. Orthoquartzite

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