1. Minerals & Rocks, Sedimentary Features

2. What is a Mineral? These are substances that: 1. Are Naturally Occurring (usually) 2. Are Solid at Room Temperature (usually) 3. Have a Specific Chemical Composition 4. Have an Ordered Atomic Structure 5. Are Inorganic (usually)

3. What’s your Mineral? Identifying a Mineral Using: A. Physical Properties 1. Crystal habit 2. Streak 3. Luster 4. Cleavage 5. Density 6. Hardness 7. Color 8. Others: magnetism, taste, flexibility

4. Three Basic Rock Types 1.Igneous 2.Metamorphic 3.Sedimentary

5. Igneous Rocks 1.Formed from the cooling and solidification of magma/lava (see texture, mineral content) a. intrusive (plutons, dikes) b. extrusive (lava flows) c. two-stage (porphyritics)

6. Intrusive Igneous Rocks Magma body forms within crust, slowly cools under ground (i.e., pluton, dike, sill)

7. Extrusive Igneous Rocks Magma escapes opening in Earth’s crust and flows as lava

8. Metamorphic Rocks Protolith is changed physically and/or chemically while being subjected to high heat and/or pressure 1. Metamorphic processes include:

9. a. regional

10. b. contact & metasomatic

11. Sedimentary Rocks Lithification – loose sediment becomes rock through: a. compaction: weight of overlying deposits compresses sediment, pushing out fluids and reducing porosity

12. compaction and/or C ementation - sediment “cemented” by minerals in solution (loss of porosity) Cementing minerals include: quartz (silica), carbonate, iron oxide, clay

13. Sedimentary Rocks Classification depends on depositional processes: Clastic – particles (clasts) transported by moving fluids…

14. Biochemical – accumulation of residues from: skeletons of siliceous organisms (chert) Radiolarians Diatoms

15. Biochemical – accumulation of residues from: dissolved skeletons of invertebrates (limestone) Carbonate “mud” Ostracod Foraminiferans

16. Biochemical – accumulation of residues from: decayed plants (coal) Coal Swamp – Pennsylvanian Period (300 Ma) central Pennsylvania

17. Chemical – precipitation of sediment from supersaturated solutions… Salt Mine - Poland Bonneville Salt Flats – Utah

18. “ Other” – sediment accumulation through occasional processes… Eolean – sand dunes Glacial – morraines

19. “ Other” – sediment accumulation through occasional processes… Volcanic Eruptions Mt. Pinatubo, Philippines Pyroclastic flow

20. “ Other” – sediment accumulation through occasional processes… Extraterrestrial Impacts Chicxulub, Yucatan Penninsula 65 Ma Meteor Crater, AZ - 45 Ka

21. What’s in that (Sedimentary) Rock? Mineral comp. Grain size Grain sphericity Grain sorting Matrix

22. Sedimentary Structures Bedding plane structures: Ripples Raindrops Mud Cracks

23. Within bedding structures Planar Bedding Cross Bedding Imbrication Graded Bedding Cut and Fill

24. Biological structures 1 Ophiomorpha 2 Diplocraterion (“yo-yo”) 3 Skolithos 4 Monocraterion Burrows Dinosaur Trackways

25. Put the Puzzle Together Rock exposure Fossil Turtle Ammonite Mosasaur Bird Bone Plesiosaur

26. Central South Dakota 73 Ma