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Sedimentary Rocks. The most common rocks on Earth’s surface!. r ocks formed from the lithification (compaction + cementation) of previously existing sediments. Processes from the Rock Cycle. l ithification : to harden and form rock.
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Sedimentary Rocks The most common rocks on Earth’s surface!
rocks formed from the lithification (compaction + cementation) of previously existing sediments
Processes from the Rock Cycle lithification: to harden and form rock
crystallization:solidification of dissolved minerals from solution
Types of Sedimentary Rocks • depends upon what they’re made of… • Clastic (LARGEST GROUP): fragments of other rocks • Chemical: dissolved minerals • Biochemical: parts from living things that weren’t actually alive (shells) • Organic: remains of once living things (plants, tissue, etc.)
Classification of Clastic Sedimentary Rocks • Classified 2 ways: • Sediment size • larger the size, the more immature, shorter distance traveled • Sediment shape • more jagged the shape, the more immature, shorter the distance traveled
Sorting of Sediments • based upon the size and shape Very Poorly Sorted Very Well Sorted
Common Clastic Rocks Sediment 1. Conglomerate 2. Breccia 3. Sandstone Siltstone 4. Shale
Chemical Sedimentary Rocks • water dissolves minerals in pre-existing rocks & then evaporates EXAMPLES: • rock salt • gypsum
Organic Rocks: remains of the living tissues of plants and animals; EX: Peat & Coal
Swamp Organic Sedimentary Rocks- Coal
Features of Sedimentary Rocks • Strata: sediment layers or beds • Geodes: hollow rock filled with silica from groundwater, forms crystals • Graded Bedding: deposits sorted according to size • Cross Bedding: movement of sand dunes • Ripple Marks: from water flow • Mud Cracks: rapid evaporation of clay • Fossils: remains from plants or animals
Cross-Bedding Bedding Planes not Parallel
Ripple Marks Beach River