Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Sedimentary Rocks Sedimentary Rocks are formed at or near the Earth’s surface No heat and pressure involved Strata – layers of rock Stratification – the process in which sedimentary rocks are arranged in layers This is a good example of Stratification SEDIMENTARY ROCKS There are 2 ways sedimentary rocks are formed 1. Clastic are made from sediments glued together 2. Non-clastic: not glued together---include chemical & biochemical/organic SEDIMENTARY ROCKS MAY CONTAIN FOSSILS. THE 2 CLASSES OF SEDIMENTARY ROCKS 1. CLASTIC Sedimentary Rocks formed from the processes of weathering, erosion (transportation), deposition, then lithification. 2. Lithification is the process of compaction and cementation of the clasts, or particles from weathering. http://geologylearn.blogspot.com/2015/11/classes-of-sedimentary-rocks.html Weathering The 2 types of weathering include physical (only size changes) and chemical (a new substance is formed). Sediments range in size from tiny pieces of clay to sand, to pebbles, and to stuff as big as boulders Sediments can be angular to rounded, and well or poorly sorted http://geologylearn.blogspot.com/2015/11/classes-of-sedimentary-rocks.html Here’s How They Form: •Layers of sediment are deposited at the bottom of oceans and lakes •As the layers build one on top of another, the pressure on the bottom layers COMPACTS the sediments together •In the empty spaces between sediments, natural glues, like calcite, CEMENT the sediments together Demo of Sedimentator Look at the processes that are occurring in this animation Clastic Process Examples of clastic sedimentary rocks include CONGLOMERATE SHALE BRECCIA SANDSTONE Clastic sedimentary rocks are classified by their grain size, and shape of the grains. http://geologylearn.blogspot.com/2015/11/classes-of-sedimentary-rocks.html http://geologylearn.blogspot.com/2015/11/classes-of-sedimentary-rocks.html Common Clastic Rocks Breccia – course, angular clasts >2mm Conglomerate – course, rounded clasts > 2mm Sandstone – clasts fine to course, >0.05 mm to <2 mm (cemented sand), occurs in many colors. Feels gritty. http://northern-arizona-uranium-project.com/breccia_pipe_anatomy https://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/p age3458.html Common Clastic Rocks Shale – made from clay, grains are small and flat. Breaks into thin pieces with sharp edges. Usually gray, brown, reddish brown or green. Siltstone – fine grained, clasts smaller than sandstone <0.05 mm, occurs in many colors due to composition or staining from surrounding minerals. Feels smooth or powdery www.geology.com/rocks 2. Non-Clastic contain 2 types: chemical and biochemical Sedimentary Rocks made from mineral crystals that formed from chemical or biochemical deposition. Here’s How They Form: •The water in the oceans, lakes, and underground is often full of dissolved minerals like halite and calcite. •Water evaporates leaving the solids behind: rock salt is formed when salt is left after evaporation and limestone is formed when calcite is left behind Chemical Sedimentary Rocks are also formed in caves where mineral-rich water drips from the ceiling, creating stalactites and stalagmites made out of limestone Limestone Limestone Cave Examples of chemical sedimentary rocks include limestone and rock salt BIOCHEMICAL OR ORGANIC Sedimentary Rocks are made from remains of once-living plants or animals (organic matter) •will be found near areas of lots of biological activity •this is the sedimentary rock type with the most fossils Biochemical sedimentary rocks include: coquina, chalk, coal and limestone COQUINA Made from shells CHALK Made from dead animals COAL Made from dead plants LIMESTONE with fossils in it In Summation: 1. Sedimentary rocks form 3 ways: Clastic --compacted & cemented 1. _________ 2. _____________ Non-Clastic : Chemically or Biochemically deposited strata 2. Sedimentary rocks are found in flat layers or _______ Fossils (remains of plants and animals) are found in 3. _______ Sedimentary Rocks. Limestone formed both chemically and organically. 4. ____________is 5. Clastic rocks are made of _____________, sediments examples are conglomerates, sandstone and shale 6. Chemically formed sedimentary rocks form from evaporating ocean water, which leaves behind _____________ evaporates like ___________, rock salt or from precipitates. 7. Some common sedimentary rocks are: Shale, limestone, sandstone, siltstone, coal, chalk, coquina, breccia, conglomerate sedimentary review/