sedimentary rocks - loudoun county public schools · 2016-11-27 · a sedimentary rock is….. rock...

Sedimentary RocksMost Sedimentary Rocks: Sediments are eroded

from rocks, perhaps transported, deposited, then compacted and lithified (hardened and turned into a

sedimentary rock).

A Sedimentary Rock is…..

rock formed from the lithification or crystallization of:

1. Minerals in solution2. Organic remains3. Materials produced by living things

(biochemical)4. Clastic Sediments (rock fragments of all

sizes)

So Sedimentary Rocks form through compacting and cementing of sediments.

Lithification-to harden and form rock (Deposition, Compaction, Cementation)

Silica Crystals

Crystallization- Solidification of dissolved minerals from solution.

Sediment- Rock fragments, dissolved minerals and remains of living and nonliving parts of

plants and animals.

Lithification: Step 1 - Deposition

Deposition (to lay down) happens when:

the Transport Agent no longer has the energy/force required to carry the Sediment

Determined by:

Size/Weight of Sediments

Amount of Energy/Force in Transport Agent

Lithification: Step 2 - Compaction

Lithification: Step 3 - Cementation

Types of Sedimentary Rocks(Classified by formation)

• Clastic-Made of fragments of other rocks.

• Chemical-Made from dissolved minerals.

• Biochemical-Made by living things, but was never alive (seashells).

• Organic-Made of the organic remains of living things.

Clastic Sediments- Fragments of pre-existing rock.

Sediments from here

Alluvial Fan

Alluvial Sediments and braided stream

Gravel Bar

Tallus Pile

Glacial Sediment

Sand Bar

Chemical Sediments- Minerals in solution in water.

Biochemical Sediments- Nonliving remains of plants and animals.

Organic Sediments-remains of the living tissues of plants and animals.

Peat- Plant remains

Examples of Sedimentary Rocks

Clastic Sedimentary Rocks

• Clastic-Made of fragments of other rocks.

Clastic Sedimentary Rocks

Claystone

Conglomerate

Shale

Clastic Sedimentary Rock Names: Particle Size

Sediment

Gravel Sand SiltClay

Conglomerate Sandstone Siltstone Shale

Clastic Sedimentary RocksConglomerate and Breccia – have gravels and cobbles

(Coarse-grained)

(Conglomerates have rounded

clasts)

(Breccia has angular clasts)

Clastic Sedimentary Rocks Sandstones – have sands (fine to coarse grained)

Arkose

Clastic Sedimentary Rocks Siltstones – have silts (fine-grained)

Clastic Sedimentary Rocks Mudstones – have clays (very fine-grained)

Sedimentary Rocks of Chemical Origin

• Chemical-Made from dissolved minerals.

Chemical Sedimentary Rocks: Precipitation and Evaporation

Chemical Sedimentary Rocks: Evaporites

Gypsum

Halite

Chemical Sedimentary Rocks: Evaporites

Salt Flats

Chemical Sedimentary Rocks: Carbonates

The Carbonate Sedimenatary Rocks are composed of mostly Calcium Carbonate.

The Carbonates are divided into:

Inorganic Carbonates (chemical sedimentary rocks)

And

Biochemical Carbonates (contains remains of living things)

Chemical Sedimentary Rocks: Inorganic Carbonates

Travertine

Chemical Sedimentary Rocks: Inorganic Carbonates

Chemical Sedimentary Rocks: Inorganic Carbonates

Travertine

Travertine Stalactites

Chemical Sedimentary Rocks: Inorganic Carbonates

Chemical Sedimentary Rocks: Inorganic Carbonate

Travertine

Chemical Sedimentary Rocks: Inorganic Carbonates

Inorganic Limestone

Chemical Sedimentary Rocks: Biochemical Carbonates

Biochemical-Made by living things, but was never alive (seashells).

Stromatolitic Limestone –(remains of photosynthetic process of algal blooms)

Biochemical Limestone –(shells)

Chemical Sedimentary Rocks: Biochemical Carbonates

Biochemical Limestone

Chemical Sedimentary Rocks: Biochemical Carbonates

CoquinaChalk

Chemical Sedimentary Rocks: Silica-based Sedimentary Rocks

Chert (Flint) Nodules

Geodes

• Organic-Made of the organic remains of living things.

Sedimentary Rocks of Organic Origin

Organic Sedimentary Rock - CoalPeat

Sediments Are Classified Based On:

1. Origin and Composition (What

they are made of).

So Remember . . .

Clastic

Sediments Are Classified Based On:

2. Size of the sediment (clastic sediments range in size from clay to boulders)

Sediment Classification II

Gravel

Pebbles

Sand

Sediment Production

Sediments are produced by:

Weathering (breaking down) and Erosion (transport) of

Parent material

by:

Chemical and Physical Processes.

Sediment Transport

WindWater

GlaciersGravity

Volcanic Eruption

Shaping of Sediments

Sorting of Sediments

Sediments are Sorted by their Transport Agents According to:

S I z e of the Sediment

Very Poorly Sorted Very Well Sorted

Sorting of Sediments

Well or poorly sorted??

• Well or poorly sorted??

Well or poorly sorted??

Sorting of Sediments: Glaciers

Sedimentary Rock Structures

Fossils: Molds

Fossils: Casts

Trilobite

Sedimentary Rocks are identified by their horizontal layers

called…….

Sedimentary Formations

Cross-Bedding

Bedding Planes not Parallel

Ripple Marks

Beach

River

Mud Cracks