II. Rocks Solid forms of matter that are created in nature that are made of one or more minerals. • The three major groups of rocks are: • Sedimentary • Igneous • Metamorphic
A. Sedimentary Rocks Sediments Fragments • Made from ________ or ________ which formed at the surface of the Earth from other rocks. • Rocks at the surface are broken down into sediments by __________ and _________. Weathering Erosion
Water Squeezes • These rocks form in ______, where the weight ________ them down and the minerals dissolved in the water act as the _______ (glue). Cement
Steps to form a Sedimentary Rock: • Weathering & Erosion • Deposition • Compaction • Cementation
Sediments • Sedimentary Rock IDENTIFICATION: • They are made up of __________, which are small fragments of other rocks. • They often show ________ _______, as one layer of sediments is deposited on another in the water. Distinct Layers
Fossils • Sedimentary rocks often contain _______ of once living organisms.
Fossils • These are the only type of rocks that can contain these ______. There are THREE different types of Sedimentary rocks: • _______: Ones that form from rock and mineral fragments which have been __________ and __________ together. Clastic Compacted Cemented Sandstone
Sandstone Siltstone Breccia Shale
Crystalline • __________: ones that form from minerals that were once dissolved in water. The water then begins to evaporate causing the minerals to deposit/precipitate out. These are also called _________. • Can only be classified by ____________, Grain size does not work!! chemical composition Rock Salt Dolostone
Bioclastic • _________: are ones that are made of the remains of organic (once living) things. Limestone Coal
Questions • What is the difference between Conglomerate and Breccia? • Conglomerate contains mostly rounded fragments, while Breccia’s fragments will be more angular. • What is the difference between Sandstone and Siltstone? • Sandstone will have larger fragments than Siltstone. • What is the particle size of Sandstone? • 0.2 to 0.006 cm
How does the composition of Conglomerate compare to the composition of Shale? • The composition of both will be close to the same, but they will have different size particles. • What is the composition of Limestone? • Limestone in made of the mineral Calcite. • What are the ways that Limestone can form? • Shell fragments are cemented together • Precipitates (falls out of) water • Biologic organisms
How does the grain size of Rock Salt compare to the grain size of Rock Gypsum, Dolostone, Coal, and Limestone? • The grain size for each of these will vary or change. • How can you classify the Clastic sedimentary rocks? • Must use their GRAIN SIZE to classify! • How can you classify the Crystalline or Bioclastic Sedimentary rocks? • Must use their COMPOSITION to classify!
ESRT p.6 – Relationship of Transported Particle Size to Water Velocity
less 0.0004cm • What are the grain sizes for the following: (use the chart on page 6 of the ESRT) • Clay: __________ than __________ • Silt: __________ to __________ • Sand: __________ to __________ • Pebbles: __________ to __________ • Cobbles: __________ to __________ • Boulders: __________ than __________ 0.0004cm 0.006cm 0.006cm 0.2cm 0.2cm 6.4cm 6.4cm 25.6cm more 25.6cm