HTML University

Science Dept.

Geology and Soils GEO 100 Notes
Sedimentary Rocks

1. Sediments
   1. Products of Decay
      1. Ions

      2. Colloids

      3. Clastics

      4. Biologic Decomposition

   2. Type of Sediments
      1. Chemical

      2. Clastics

      3. Biological

2. Lithification
   1. Compaction

   2. Cementation
      1. Calcite - CaCO₃

      2. Hematite - FeO

      3. Silica - SiO₂

3. Environments of Depostion
   1. Terrestrial
      1. Desert

      2. Cave

      3. Floodplain

      4. Glacial

   2. Marine
      1. Offshore

      2. Deep Water

      3. Organic Reefs

   3. Transitional
      1. Lagoons

      2. Deltas

      3. Beaches

      4. Estuary

      5. Tidal Flats

      6. Barrier Islands

4. Clastics
   1. Texture
      1. Grain Size
         1. Boulders greater than 256mm
         2. Cobbles greater than 64mm
         3. Pebbles greater than 4mm
         4. Granules greater than 2 mm
         5. Sand greater than 1/16 mm
         6. Silt greater than 1/256 mm
         7. Clay smaller than 1/256 mm

      2. Sorting

      3. Shape - Angular vs Rounded

      4. Spacing

   2. Composition

      	Quartz - 90%+	Quartz K Feldspar	(Quartz) Rock Fragments
      Coarse	Quartzose Conglomerate or Breccia	Arkosic Conglomerate or Breccia	Graywacke Conglomerate or Breccia
      Sand	Quartzose Sandstone	Arkosic Sandstone	Graywacke Sandstone
      Silt	Quartzose Siltstone	Arkosic Siltstone	Graywacke Siltstone
      Clay	Siliceous Shale	Feldspathic Shale	Graywacke Shale

5. Chemical
   1. Texture - Crystalline

   2. Composition
      1. Halite - NaCl

      2. Gyprock - CaSO₄

      3. Limestone - CaCO₃

      4. Dolostone - (Mg,Ca)CO₃

      5. Some Cherts, Jasper - SiO₂

6. Biological
   1. Composition
      1. Coquina - CaCO₃

      2. Fossiliferous Iimestone - CaCO₃

      3. Chalk - CaCO₃

      4. plant -> peat -> lignite -> coal

      5. Some Cherts, Flint - SiO₂

      6. Diatomite

7. Sedimentary Features and Structures
   1. Stratification
      1. Difference in Mineral Composition

      2. Color

      3. Texture

   2. Fossils

   3. Ripplemarks
      1. Oscillation Ripple Marks

      2. Current Ripple Marks

   4. Raindrop Imprints

   5. Mud Cracks

   6. Graded Bedding