SEDIMENTARY ROCKSSire 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 Examples are: sandstone, shale, limestone;

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

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

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)

Identifying Sedimentary Rocks

Rock Grain Color Hardness

Sandstone Medium Red or brown Hard

Mudstone Fine Black gray red or green

Hard

Clay Fine Red or brown Soft

Conglomerate Mixed Red or brown ,edium

Shelly limestone Medium with shells

Brown or gray Medium

Chalk Fine White soft

What would be the four stages in order of making a sedimentary rock?

weathering, transportation, deposition, compaction/cementation

Which sedimentary rock is most likely to be changed to slate during regional metamorphism?

1. breccia 2. conglomerate 3. dolostone 4. shale

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

Sedimentary Rocks for The Soul

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

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

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

Travertine Evaporite Forms in caves around hot springs

Chalk Major mineral within is calcite A type of limestone made from tiny

pieces of the mineral calcite

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

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

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

Gritstone Similar to sandstone but has larger

particles and is not rounded and feels rougher

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

Mudstone Made of small particles too small to see

without microscope Black, gray, red, or green Very brittle

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

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

Chert Sedimentary rock with microcrystalline

and quartz

Dolostone Hard to distinguish from limestone Carbonate sedimentary rock Minerals composition includes calcite,

dolomite, and aragonite

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

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

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