Diagrams for Sedimentary Rocks,

Environments, and Structures

(Depending upon your printer, you may have to adjust your page and/or printer settings to make a print out of the following diagrams.  These adjustments may include things like page orientation, page reduction (80% vs. 100%), color vs. grayscale, etc.  If in doubt, do a print preview prior to printing!)  I recommend either color or grayscale for these images.

The following pictures depict various Sedimentary structures.

Original horizontality as shown in these sedimentary rock layers.

Original Horizontality as shown in these sedimentary rock layers.

Ripple Marks associated with dune deposits

Ripple marks associated with sand dunes.

Mud Cracks

Mud cracks.

Sand dunes with ripple marks

Sand dunes with ripple marks.

 

The following is a

 

CLASSIFICATION OF SEDIMENTARY ROCKS

 

Clastic / Detrital Sedimentary Rocks

Texture / particle size

Composition

Comments

Rock Name
Coarse grained

( >2 mm)

 Quartz, quartzite, and chert are dominant Rounded rock fragments of any rock type. CONGLOMERATE
Angular rock fragments of any rock type. BRECCIA
Coarse to fine grained Fragments of any rock type (associated with glaciers) Poorly sorted, nonstratified, and angular rock fragments.  Sometimes the larger particles are elongate. TILLITE
Medium grained

(1/16 - 2 mm)

 Primarily Quartz grains Usually moderately to well sorted and rounded. QUARTZ SANDSTONE SANDSTONE
Quartz and at least 25% K-Feldspar grains Usually from rapid erosion, with visible feldspar grains. ARKOSE SANDSTONE
Quartz grains, small rock fragments and clay minerals. Often gray in appearance. GRAYWACKE SANDSTONE
Fine grained (1/256 - 1/16 mm) Fine grained quartz and clay minerals. Silt-sized particles with a gritty feel. SILTSTONE
Very fine grained 

(< 1/256 mm)

 Very fine grained quartz and clay minerals. Clay-sized particles with a soft feel SHALE (Mud- or Clay-stone)

 

Chemical or Biochemical/Organic rocks

Texture / Particle size

Composition

Comments

Rock Name
Medium to coarse crystalline grains Calcite 

( CaCO3 )

 Crystalline texture.  Forms from a fine-grained lime mud. CRYSTALLINE LIMESTONE
Microcrystalline Exhibits Conchoidal fracture MICRITE LIMESTONE
Aggregates of Oolites Oolites (round spherical fossil features) OOLITIC LIMESTONE
Fossiliferous Loosely cemented fossils and fossil fragments with little matrix. COQUINA
Coarse grained with finer grained matrix Abundant fossils in a calcareous (calcite) matrix FOSSILIFEROUS LIMESTONE
Microscopic Shells of microscopic organisms, clay, very soft. CHALK
Banded Calcite Usually forms as dripstones - stalactites or stalagmites. TRAVERTINE
Similar to Limestone

Dolomite

(CaMg(CO3 )2)

 Also known as dolomite, reacts with acid only if powdered. DOLOSTONE
Cryptocrystalline

Chalcedony (SiO2)

 Hard, dense masses or beds and exhibits conchoidal fracture. CHERT
Fine to Coarse crystalline grains

Gypsum 

(CaSO4  * 2H2O)

 An evaporite, Inorganic precipitate ROCK GYPSUM
Fine to Coarse crystalline grains Halite (NaCl) An evaporite, Inorganic precipitate. Salty. ROCK SALT
Microscopic (SiO2) Silica Shells of microscopic organisms (Diatoms), very soft and similar to chalk. DIATOMACEOUS EARTH
Fibrous Brownish plant material Soft, Porous. Will burn. PEAT
Dense Carbon Highly altered, compacted, carbonized plant remains.  Will burn. COAL

The following is a

 

Classification of Chemical and Biochemical Sediments and Sedimentary Rocks

SEDIMENT

ROCK

CHEMICAL COMPOSITION

MINERALS PRESENT
Carbonate sand and mud Limestone Calcium carbonate

CaCO3

Calcite (aragonite)
No primary sediment Dolostone Calcium-Magnesium Carbonate

(CaMg(CO3 )2)

Dolomite
Iron Oxide sediment Iron Formation Iron Silicate; oxide; carbonate

FeO3; FeCO3

Hematite

Limonite

Siderite
Evaporite sediment Evaporite Sodium chloride; calcium sulfate

NaCl; CaSO4

Gypsum

Anhydrite

Halite

Other Salts
Siliceous sediment Chert Silica    (SiO2)

Opal

Chalcedony

Quartz
Peat, organic matter Organics Carbon  (C)

(Coal)

(Oil)

(Gas)
No Primary sediment Phosphorite Calcium Phosphate

Ca3 (PO4)2

Apatite

 

Table 7.6

Press and Siever:  Understanding Earth                     Copyright  1994  W.H. Freeman and Company

The following is a description of sedimentary environments and the sediments produced.

 

Clastic Sedimentary Environments

Environment

Agent of Transportation, Deposition

Sediments

Alluvial

Rivers

Sand, gravel, mud

Lake

Lake currents, waves

Sand, mud

Desert

Wind

Sand, dust

Glacial

Ice

Sand, Gravel, mud

Delta

River + waves, tides

Sand, mud

Beach

Waves, tides

Sand, gravel

Shallow Shelf

Waves, tides

Sand, mud

Deep Sea

Ocean currents, settling

Mud

 

Major Chemical and Biochemical Sedimentary Environments

Environment

Agent of precipitation

Sediments

Carbonate (includes reef, bank, deep sea, etc.)

Shelled organisms, inorganic precipitation from seawater

Carbonate sands  and muds, reefs

Evaporite

Evaporation of Seawater

Gypsum, halite, other salts

Deep Sea

Shelled organisms

Silica  (siliceous) sediment

Swamp

Vegetation

Peat

The following diagram correlates environment with sediments produced and the resulting sedimentary rock type.

Sedimentary rock environments and corresponding sediments and sedimentary rocks

 

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