Presentation on theme: "AIM: How are sedimentary rocks formed, classified and used? OBJ: Given notes and activity sheet SWBAT explain how sedimentary rocks are formed, classified."— Presentation transcript:
AIM: How are sedimentary rocks formed, classified and used? OBJ: Given notes and activity sheet SWBAT explain how sedimentary rocks are formed, classified and used with 70% accuracy. DN: HW Check- Igneous Rock Activity Sheet Watch video https://www.youtube.com/watch?v=wxX8KPzV6xU ACT: Introduction to Sedimentary Rocks (Notes) Text, Read p.152-156 HW: Complete Sedimentary Rocks Activity Sheet; Work on MR Review Sheets; Mineral & Rocks Exam, March 20 https://www.youtube.com/watch?v=wxX8KPzV6xU
Sedimentary Rock Notes Sedimentary Rock: forms when sediment undergoes erosion, deposition, accumulation, compaction and/or cementation. Sediment: small, solid pieces of rock or living things (seashells, bones, leaves, stems). Weathering: breakdown rock (mountains) into sediment by: Physical weathering: ice wedging, collision of particles by abrasion in running water or wind action Chemical weathering: dissolution by organic acids, acid rain. Erosion: transport/movement of sediment by running water, ice or wind.
Deposition: the process by which sediments settle out (to the bottom) from a column of water or wind carrying it. Accumulation/Burial: the build up of sediments from bottom to top froming thick layers gradually over long periods of time. Compaction: accumulated sediments squeeze together under great pressure Cementation: sediments glued together as natural mineral cements harden from solutions.
Deposition of Sediments decreasing siltstone shale chemical limestone conglomerate sandstone
Types of Sedimentary Rock Sedimentary Rocks are classified into 3 major groups based on the type of sediments: Clastic/Fragmental Rocks: Most sedimentary rocks are made up of broken pieces of other rocks (rock fragments) which underwent compaction and possibly cementation. Clastic rocks are classified based on the size & shape of the rock fragments. Example: Shale - clay particles Siltstone – silt Sandstone – sand Conglomerate – rounded pebbles/gravel Breccia – angular pebbles/gravel
Sedimentary Rock Notes Organic/Bioclastic Rocks: form from the accumulated remains of plants & animals into thick layers under compaction and/or cementation. Example: Coal – remains of plants Coquina – remains of seashells loosely cemented together Fossiliferous limestone – remains of seashells, dense, well cemented together.
Sedimentary Rock Notes Crystalline/Chemical Rocks: the process by which minerals that are dissolved in a solution, crystallize out by evaporation and precipitation. Example: Chemical limestone – dissolved calcite in ocean water precipitates out; homogeneous, microcrystalline, no fossils Rock salt – evaporation of inland seas, lakes
Sedimentary Rock Notes Uses of Sedimentary Rocks Tools – flint arrowheads for hunting Building – limestone & sandstone (White House, Washington, DC) Cement & Steel – limestone used.