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Sedimentary Rocks

Sedimentary Rocks. Sire Kassama 2014. Intro to Info. Sedimentary: fragments of sediment cemented together 75% land area composed of sedimentary rock Lithification : conversion of sediment to sedimentary rock Sediment deposited in horizontal layers called strata or beds

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Sedimentary Rocks

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  1. Sedimentary Rocks Sire Kassama 2014

  2. Intro to Info • Sedimentary: fragments of sediment cemented together • 75% land area composed of sedimentary rock • Lithification: conversion of sediment to sedimentary rock • Sediment deposited in horizontal layers called strata or beds • Examples are: sandstone, shale, limestone;

  3. Intro to Info • Stalactites: limestone is left behind when water evaporates and hang down from the roof; take thousands of years to form • Stalagmites: limestone is left behind when water evaporates and forming upward from the floor • Most sedimentary rocks are clastic or made from pieces of other rocks

  4. Types of Sedimentary Rock • Clastic: weathering of pre-existing rocks transported to basin; texture consists of clasts (large pieces such as sand or gravel), matrix (mud or fine grained sediment), cement (calcite, iron oxide, or silica) • Organic • Chemical: Also biochemical sedimentary rock; evaporites, carbonates, and siliceous rocjs; firm within depositional basin from chemicals dissolved in seawater; chemicals may be removed and made into rocks with assistance from shell growth or biological processes

  5. Clastic Sedimentary Rocks • Clastic sedimentary rocks are classified according to texture (grain size): • 1. Gravel: Grain size greater than 2 mm If rounded clasts = conglomerate If angular clasts = breccia • 2. Sand: Grain size 1/16 to 2 mm. Sandstone (various types) • 3. Clay: Grain size less than 1/256 mm Shale (if fissile)

  6. Identifying Sedimentary Rocks

  7. What would be the four stages in order of making a sedimentary rock? weathering, transportation, deposition, compaction/cementation

  8. Which sedimentary rock is most likely to be changed to slate during regional metamorphism? 1. breccia 2. conglomerate 3. dolostone 4. shale

  9. Need To Know on Rocks • ROCK NAME • TYPE ( Igneous, Sedimentary, metamorphic) • FORMATION • Igneous (Extrusive, Intrusive) (volcanic, plutonic) (felsic or mafic) • Sedimentary ( Clastic, chemical, biochemical, organic) • Metamorphic (Regional, Contact Metamorphism) (low grade-high grade) • ENVIRONMENT • TEXTURE • Igneous (phaneritic, aphanitic, porphyritic) • Sedimentary (grain size) • Metamorphic Foliated or non-foliated • HARDNESS RANGE • MINERALS • PHYSICAL DESCRIPTION • (Color) • USES • OTHER PROPERTIES

  10. Sedimentary Rocks for The Soul

  11. Limestone • Is composed of calcite • Fossils are likely to be found within limestone; carbonate sedimentary rock • Hardness: 4 • Made from shells and fossils • Shelly limestone full of small shells • Another type of limestone is called coquina that is mostly made from shells of sea animals including snails • Oolitic limestone: delicately rolled spheres of calcite • White, gray, or black • Found in Belgium, China, England, Egypt, US • Used Egyptian pyramids

  12. Shale • Not a clastic rock, but rather an organic sedimentary rock • splintery rock made from weathering of other clastic rocks • Most common sedimentary rock • Minerals: kaolinite, smectite, and illite • Used for roof tile, bricks, and pottery when ground up • Hardness: 3 • Fossil rock

  13. Bauxite • Main source of aluminum • Contains more than one mineral so is not considered mineral • Forms because of the weathering process of soils mostly in tropical regions • Not easily identifiable by streak and hardness tests

  14. Travertine • Evaporite • Forms in caves around hot springs

  15. Chalk • Major mineral within is calcite • A type of limestone made from tiny pieces of the mineral calcite

  16. Coal • Organic sedimentary rock • With increased pressure, coal becomes blacker, harder and better for burning • Most coal formed in the swampy Carboniferous period • Mineral: carbon • Hardness: 2 • Used to generate electricity

  17. Anthracite • Black, shiny • Found in Australia, China, US • Type of coal • Densest type of coal

  18. Sandstone • A clastic sedimentary rock • Made from grains of sand stuck together • Rough texture like sand paper • Grains are rounded • Made mainly of mineral quartz • Found in Brazil, China, India, US • Used in the making of buildings • Minerals: quartz and feldspar

  19. Gritstone • Similar to sandstone but has larger particles and is not rounded and feels rougher

  20. Clay • Clastic sedimentary rock • Made of small particles of rock that are too small to see even with a microscope • Becomes sift and easy to break when wet • Used in facial masks • Minerals found within are kaolinite, smecite and illite • 2-3 on hardness scale

  21. Mudstone • Made of small particles too small to see without microscope • Black, gray, red, or green • Very brittle

  22. Conglomerate • Made of a mixture of different sized rounded rock such as pebbles, boulders, and sand • Coarse grained clastic rock • Found in high energy environments

  23. Evaporite • Chemical sedimentary rock • Minerals: qypsum and halite • In dry regions, where limited fresh water flows, evaporites begin to dry out, as the water evaporates, minerals dissolved in water begin to harden and crystallize • Used in chemical industry for hydrochloric acid, plastics, and plaster of Paris

  24. Chert • Sedimentary rock with microcrystalline and quartz

  25. Dolostone • Hard to distinguish from limestone • Carbonate sedimentary rock • Minerals composition includes calcite, dolomite, and aragonite

  26. Other Resources • The following questions and answers are from the New York State Regents Website: http://www.regentsprep.org/Regents/core/questions/topics.cfm?Course=ESCI • Geology.com

  27. Carbonate: fossiliferous limestone composed of fossils in limestone matrix; oolitic limestone is dossil hash cemented together; chalk made of planktonic organism such as coccolithophores • Siliceous rocks: dominated by silica; form from silica-secreting organisms such as diatoms, radiolarims, or sponges; chert is formed through chemical reaction of silica in solution replacing limestone • Diatomite: siliceous rock; made of diatoms • Coal: electricity: chemicals derived are used in plastics, tar, synthetic fibers, medicine, and fertilizer

  28. Organic Sedimentary Rocks (Coal) • Plant fragment rocks accumulate in swamps or marshes • Lack minerals which must be organic • Peat: porous mass of brownish plant resembling moss • Lignite: crumbly and black • Bituminous coal: dull to shiny, black sooty with visible layers • Anthracite coal: very shiny, slightly golden, low density, no soot

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