Rock Cycle – Sedimentary RocksRock Cycle – Sedimentary Rocks

What Rocks Tell Us Rock Type How Classified What it Tells Us

IgneousComposition Tectonic Setting

Texture Cooling History

Sedimentary

Chemical Composition

Surface Environment

Grain SizeEnergy of Environment

Metamorphic

Composition Original Rock Type

Mineral MakeupTemperature, Pressure

Texture Degree of Change

Identification of all three rock groupsis based on

TEXTURE and COMPOSITION

Identification of all three rock groupsis based on

TEXTURE and COMPOSITION

the appearance of thethe appearance of therockrock

the appearance of thethe appearance of therockrock

what the rock is madewhat the rock is madeout of – type of mineralsout of – type of mineralswhat the rock is madewhat the rock is made

out of – type of mineralsout of – type of minerals

Love it, Learn it, Live it , be one with it!Love it, Learn it, Live it , be one with it!

SEDIMENTARY ROCKSThere 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 WILL CONTAIN FOSSILS.

SEDIMENTARY ROCKS FORM IN LAYERS CALLED STRATA

Oldest rocks are on the bottom….youngest on top

This is a good example of Stratification

1. CLASTIC Sedimentary Rocks are made from sediments that come from pre-existing rocks that have been weathered (breaking down into smaller pieces) and eroded (transported away) then glued together.

THE 2 CLASSES OF SEDIMENTARY ROCKS

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

Clastic rocks form in a process called lithificaton which means compaction and cementation are occurring

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

Look at the processes that are occurring in

this animation

Clastic Process

Examples of clastic sedimentary rocks include

CONGLOMERATEBRECCIA

SANDSTONESHALE

2. Non-Clastic contain 2 types: chemical and biochemical

CHEMICAL Sedimentary Rocks are made from mineral crystals that formed from chemicals dissolved in water.

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

Limestone Cave

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

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)

COQUINAMade from

shells

CHALKMade from dead

animals

Biochemical sedimentary rocks include: coquina, chalk, coal and limestone

•this is the sedimentary rock type with the most fossils

•will be found near areas of lots of biological activity

COAL

Made from dead plants

LIMESTONE with

fossils in it

How is a sedimentary Rock formed???How is a sedimentary Rock formed???How is a sedimentary Rock formed???How is a sedimentary Rock formed???

Pre-existingPre-existingRockRock

Pre-existingPre-existingRockRock

ErosionErosionErosionErosion

Water, Wind, Water, Wind, IceIce

Water, Wind, Water, Wind, IceIce

Breaks downBreaks downPre-existing rockPre-existing rockBreaks downBreaks downPre-existing rockPre-existing rock

SedimentSedimentSedimentSediment

TransportedTransportedTransportedTransportedLakesLakesLakesLakes

RiversRiversRiversRivers

Depos

ited

Depos

ited

Depos

ited

Depos

ited

CompactedCompactedCementedCemented

CompactedCompactedCementedCemented

LithifiedLithifiedLithifiedLithified SedimentarySedimentaryRockRock

SedimentarySedimentaryRockRock

Why is the earthWhy is the earth’’s surface 75% sedimentary rocks?????????s surface 75% sedimentary rocks?????????Why is the earthWhy is the earth’’s surface 75% sedimentary rocks?????????s surface 75% sedimentary rocks?????????

AMAZING EARTH SCIENCE FACTS

1. Sedimentary rocks form 3 ways:1. _________ --compacted & cemented2. Chemical3. _______________

2. Sedimentary rocks are found in flat _________ or strata.

3. _______ are found in Sedimentary Rocks.

4. ____________is formed both chemically and organically.

Clastic-

layers

Fossils

Limestone

Biochemical

5. Clastic rocks are made of _____________, examples are conglomerates, sandstone and shale

6. Chemically formed sedimentary rocks form from _____________ ocean water, which leaves behind evaporates like ___________.

sediments

evaporatingrock salt

Sedimentary Rock Identification LabSedimentary Rock Identification Lab

Sandstone Arches

Three major categories of Sedimentary Rocks

Clastic Sedimentary rocks

Chemical Sedimentary rocks

Bio-chemical (bio-clastic) Sedimentary rocks

Three major categories of Sedimentary Rocks

Clastic Sedimentary rocks

Chemical Sedimentary rocks

Bio-chemical (bio-clastic) Sedimentary rocks

Clastic (inorganic-detrital)rocks are composed of particles or grains. Rockname is dependent on grain size.

Decreasing grain size

Decreasing grain size2+ mm2+ mm

2 mm2 mm

1/16 mm1/16 mm

1/256 mm1/256 mm

Chemical Rocks – inorganic, non-clastic rocks that are commonly the result of evaporation and precipitation

Chemical rocks contain no fossils, or biological material but may react with HCl

Chemical Rocks – inorganic, non-clastic rocks that are commonly the result of evaporation and precipitation

Chemical rocks contain no fossils, or biological material but may react with HCl

The Great Salt Lake, Utahhalite (salt) crystals

The Great Salt Lake, Utahhalite (salt) crystals

Calcium Carbonate (CaCO3) chemical rocks (evaporation / precipitation processes)

Calcium Carbonate (CaCO3) chemical rocks (evaporation / precipitation processes)

Chemically precipitated SiO2Chemically precipitated SiO2

Bio-chemical (bio-clastic, biogenic) rocks – result from animal and plant secretions. The term clasticindicates that these rocks contain fossils or parts of plantsshells, compacted plat material

Bio-chemical (bio-clastic, biogenic) rocks – result from animal and plant secretions. The term clasticindicates that these rocks contain fossils or parts of plantsshells, compacted plat material

Animal partsAnimal parts

Cemented shell fragmentsCemented shell fragments

Lithified plant materialLithified plant material

Classification ProcedureClassification Procedure

Step 1: Determine if the rock is clastic or non-clastic Step 1: Determine if the rock is clastic or non-clastic

Step 2: If the rock is clastic, determine the grain size and diagnostic properties. Make the ID.Step 2: If the rock is clastic, determine the grain size and diagnostic properties. Make the ID.

Step 3: If the rock is not clastic, determine if the rock is either chemical or bioclastic

chemical – will not contain particles such as grains and organic material. Test rock to observe fizzing (carbonates) Match diagnostic properties on chart for ID

bio-clastic- rock will be composed of particles that are organic- animal parts, plant secretions.

Test rock to observe fizzing (carbonate) Match diagnostic properties on chart for

ID

Step 3: If the rock is not clastic, determine if the rock is either chemical or bioclastic

chemical – will not contain particles such as grains and organic material. Test rock to observe fizzing (carbonates) Match diagnostic properties on chart for ID

bio-clastic- rock will be composed of particles that are organic- animal parts, plant secretions.

Test rock to observe fizzing (carbonate) Match diagnostic properties on chart for

ID