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Sediments and Sedimentary Rocks Sediments and Sedimentary Rocks And Sedimentary Rocks Metamorphic Rocks Weathering/Erosion Heat and Pressure Magma Sediment Igneous Rocks Sediments (soft) Material (such as gravel, sand, mud, and lime) that is transported by wind, water, ice, or gravity; Material that is precipitated from solution; Deposits of organic origin (such as coal and coral reefs). Sedimentary Rock (hard) Rock formed by the accumulation and consolidation of sediment. Sediments - unconsolidated particles created by 1. The weathering of rock 2. The secretions of organisms or decomposition of organic matter 3. Chemical precipitation Sedimentary Rocks Composed of lithified sediments - by compaction - by cementation Two (Textures) clastic (detrital) non-clastic Types of Sediments Clastic Non-clastic 1. Biochemical 2. Chemical Igneous Rocks Sedimentary Rocks 1. Phaneritic 1. Clastic 2 .Aphanitic 2. Non-clastic * Glassy * Vesicular * Biochemical * Chemical Types of Sediments 1. Clastic – broken fragments of rock produced by weathering. Range in size from largest boulder to smallest clay particle. Classified according to size. Found everywhere on the Earth. Clastic Texture Texture - Size, shape, and distribution of particles that collectively make up a rock •Size •Rounding •Sorting Clastic Sediment Size Clastic Texture Roundness – the shape of sediment grains. Related to the distance a sediment has been transported. Roundness / Sphericity of Sediments Size Rounding Sphericity Sorting Clastic Sediments Sorting Sorting – separation of sediments by grain size and density. Poorly sorted – sediment with a wide range of grain sizes. Well sorted – sediment with a small range of grain sizes. Sorting of Sediments Sorting - a function of transported 1. Water 2. Wind 3. Glaciers Texture and Transport Distance In general, as transport distance increases, rounding and sorting increase. Examples: Breccia – cemented close to source Conglomerate – transported then cemented Depositional Environments of Sedimentary Rocks Smaller….Rounder…..Better Sorted Clastic Sedimentary Rocks Nonclastic Sedimentary Rocks Basin Source Downstream Beach Offshore (Playa Lake) Halite, Gypsum, Chert (Evaporites) Coal Reef Swamp Coquina Limestone Transport by Water Saltation – particles move downstream in short jumps. Bed load – material transported by saltation Suspended load – material carried in water for long distances Transport by Water Sorting by Water Graded Beds Graded Beds Fining up Sorting by Wind Cross Bedding – water or wind Sorting by Glaciers Clast Size / Rock Name Relationship Large Clasts Small Clasts Breccia Formed at the source Conglomerate – Formed near the source Sandstone – Down stream to just off shore Tidal Flat Deposit Stream Deposit Off-Shore Environments Strata Stratum Stratigraphy Stratigraphic - relating to layered sedimentary rocks Bedding – Layering or stratification in sedimentary rock Types of Sediments 2. Biochemical (non-clastic) – composed of remains of plants or animals. Biochemical Sediments (non-clastic) Terestrial Sediments - mainly plant matter Marine Sediments - mainly carbonates Corals - Large components of reefs. Bivalves, Gastropods, Foraminifers - Whole or partial skeletons form sand and gravels. Aglae, Crinoids, Echinoderms, Bryozoans disintergrate to form some sand particles and lime mud. Diatoms, Radiolaria – Bedded chert SiO2 Coral (carbonate) Foramanifera Diatoms Types of Sediments 3. Chemical (non-clastic) – formed by minerals precipitating from solution. - Inorganic process, no biological activity involved. Bonneville Salt Flats Chemical Sediments (non-clastic) 1. Terestrial - Evaporites: Gypsum - CaSO4 . H2O Anhydrite - CaSO4 Halite NaCl 2. Marine Carbonates - CaCO3 (Whitings) Sedimentary Rocks Clastic Rock – composed of fragments of preexisting rocks. Non-clastic Rock – composed of chemical precipitates or biogenic matter. Ripple Marks Mud Cracks Burrows Depositional Environments Where sedimentary rock live! Delta building into lake. SE Alaska. small fan emerging from a wineglass canyon. Death Valley, CA. Ripples on tidal flat, SE Alaska Son-Kul River, Tien Shan Mtns., Kyrgyzstan Peanut Brittle Conglomerate in Southern Illinois