Definition
Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age
A sedimentary rock, deposit of a submarine turbidity currents and are composed of layered particles
History
Origin
Western Australia, Minnesota
European Foreland Basins
Discoverer
Johann Gottlob Lehmann
Arnold H. Bouma
Etymology
From its formation process
From Medieval Latin turbiditas, from Latin turbidus (turbid). Turbidity current is from 1939
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Family
Group
-
-
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
Texture
Banded, Trellis
Mud-rich, Sandy
Color
Red, Reddish Brown
Black, Brown, Green, Grey, Pink
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Layered, Banded, Veined and Shiny
Dull and Banded
Architecture
Interior Uses
Decorative Aggregates, Homes
Bathrooms, Countertops, Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing, Whetstones
Curbing
Industry
Construction Industry
As Dimension Stone, Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
As a touchstone, Cemetery Markers, Creating Artwork
Cemetery Markers, Creating Artwork
Types
Algoma-type , Lake Superior-type, Superior-type and Taconite
Sedimentary rock
Features
Is one of the oldest rock
High silica content, Host Rock for Lead
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Present
Present
Formation
The banded iron layers are formed in sea water when oxygen is released by photosynthetic cyano-bacteria. The oxygen then combines with dissolved iron in ocean to form insoluble iron oxides, which precipitated out, forming a thin layer of banded iron formation on ocean floor.
Turbidite is a type of sedimentary rock formed when a river carries or transports pieces of broken rock as it flows. These particles then settle down and are subjected to high temperature and pressures hence forming Turbidite.
Composition
Mineral Content
Hematite, Magnetite, Quartz
Coesite, Quartz, Sand
Compound Content
Fe, Iron(III) Oxide, Silicon Dioxide
CaO, Carbon Dioxide, MgO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
-
Weathering
✔
✘
✔
✘
Types of Weathering
Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Coastal Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
5.5-63
1
7
👆🏻
Grain Size
Large and Coarse Grained
Fine to Coarse Grained
Fracture
Uneven, Splintery or Conchoidal
Splintery
Streak
White
White, Greenish White or Grey
Porosity
Highly Porous
Very Less Porous
Luster
Earthy
Metallic
Compressive Strength
220.00 N/mm2200.00 N/mm2
0.15
450
👆🏻
Cleavage
-
Disjunctive
Toughness
1.5
2.4
Specific Gravity
5.0-5.32.46-2.73
0
8.4
👆🏻
Transparency
Translucent to Opaque
Opaque
Density
-9999 g/cm31.6-2.5 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
3.20 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
-
Africa
Kenya, Morocco, South Africa, Tanzania
Western Africa
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Austria, Belarus, Romania, Switzerland, United Kingdom
Others
Greenland, Mid-Atlantic Ridge
-
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Bolivia, Brazil
Brazil, Colombia
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
New Zealand, Western Australia