Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Earth Systems 3209 Unit: 3 Earth’s Materials Reference: Chapters 2, 3, 6, 7; Appendix A & B

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Clastic Sedimentary Environments Unit 3: Topic 4.4 Focus on...  identifying different clastic sedimentary rocks and relating the rocks to the environment in which they form.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Particle SizeSediment NameRock Name Boulder & PebbleGravelConglomerate or Breccia Sand Sandstone Silt & ClayMudSiltstone & Shale  Consist of solid particles which results when physical weathering breaks down rocks. The weathered products include pebbles, sand, silt and clay.  These rocks usually form in water environments such as: rivers, lakes, oceans, but can also form in deserts.  Geologist mainly use particle size to distinguish between clastic sedimentary rocks, as seen in the table below: Clastic Sedimentary Rocks

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Examples of clastic sedimentary rocks include: 1)Conglomerate  Consist of poorly sorted rounded gravel size particles.  Form in shoreline and river environments where mixtures of sediments are deposited.  The rounded rock fragments suggest that the sediment was transported great distances. This allowed angular edges to be eroded to produce rounded fragments. Clastic Sedimentary Rocks

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Examples of clastic sedimentary rocks include: 2) Breccia  Consist of poorly sorted, angular gravel size particles.  Form in shoreline and river environments where mixtures of sediments are deposited.  The angular rock particles suggest that the sediment was not transported far from the place where it originated. Thus angular fragments. Clastic Sedimentary Rocks

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Examples of clastic sedimentary rocks include: 3) Sandstone  Consist of well sorted sand size particles.  Form in shoreline environments (deltas) where sand is deposited.  Second most abundant sedimentary rock  Sand size sediment is a result of erosion due to wind, water, and ice acting on rock fragments over a long period of time. Clastic Sedimentary Rocks

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Examples of clastic sedimentary rocks include: 4) Shale (Siltstone)  Consist of fine clay and silt sized particles compacted to form thin layers.  Form in quiet (slow moving) water environments; - deep ocean & continental slope - lakes - floodplains (siltstone)  Commonly contain organic material within the original clay or mud which form fossils. Clastic Sedimentary Rocks

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Summary Clastic Sedimentary Rock Environments EnvironmentRock Types Fluvial (Rivers)breccia, conglomerate, sandstone, siltstone, shale, mudstone Lagoonalsiltstone, shale, mudstone Beachesconglomerate, sandstone Deep Marine (Ocean)turbidites, shale dominantly chemical sedimentary rocks Shallow Marinevarious types of clastic and carbonates

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Example 1: When a river slows, which sediment is the first to settle? a)siltb) sand c) clayd) pebbles Over long periods of time deposits of silt and clay compact to form which sedimentary rock? a)basaltb) conglomerate c) shaled) limestone

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Example 2: Which is a clastic sedimentary rock? (A) breccia(B) gypsum (C) rock salt(D) travertine The diagram to the right demonstrates which sedimentary rock? (A) breccia(B) conglomerate (C) sandstone(D) shale

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Your Turn... Take the time and complete the following questions... (Solutions to follow) Question: With reference to the diagram, explain why the two different sedimentary rocks developed in the areas indicated.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Solutions... Question: With reference to the diagram, explain why the two different sedimentary rocks developed in the areas indicated. It is evident from the diagram that the current direction is from left to right. Velocity of the current decreases with progression from left to right. It is this decrease in the velocity of the current that causes the sediment particles to be horizontally sorted. The coarse/large sediment particles are deposited first, closest to the shoreline, and are lithified to form the sedimentary rock called conglomerate. The fine/small sediment particles are deposited furthest from the shoreline and are lithified to form the sedimentary rock called shale.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Summary... Overview of Points covered:  Clastic Sedimentary rocks include;  Conglomerate  Breccia  Sandstone  Siltstone  Shale  Clastic Sedimentary environments include;  Fluvial (Rivers)  Lagoonal  Beaches  Deep Marine (Ocean)  Shallow Marine