Definition
Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
History
Origin
Western Australia, Minnesota
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Discoverer
Johann Gottlob Lehmann
Johann Gottlob Lehmann
Etymology
From its formation process
From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
-
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Banded, Trellis
Clastic, Splintery
Color
Red, Reddish Brown
Black, Brown, Buff, Green, Grey, Red, Yellow
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Layered, Banded, Veined and Shiny
Muddy
Architecture
Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Curbing, Whetstones
Curbing
Industry
Construction Industry
As Dimension Stone, Used for flooring, stair treads, borders and window sills.
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Medical Industry
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Antiquity Uses
Artifacts
Artifacts, Sculpture
Other Uses
Commercial Uses
As a touchstone, Cemetery Markers, Creating Artwork
Creating Artwork, Pottery
Types
Algoma-type , Lake Superior-type, Superior-type and Taconite
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Features
Is one of the oldest rock
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Archaeological Significance
Monuments
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Famous Monuments
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Jantar Mantar in India
Sculpture
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Famous Sculptures
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Pictographs
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Petroglyphs
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Figurines
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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.
Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.
Composition
Mineral Content
Hematite, Magnetite, Quartz
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Compound Content
Fe, Iron(III) Oxide, Silicon Dioxide
Ca, Fe, Mg, Silicon Dioxide, Sodium
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, Glacier Erosion
Physical Properties
Hardness
5.5-63
1
7
👆🏻
Grain Size
Large and Coarse Grained
Very fine-grained
Fracture
Uneven, Splintery or Conchoidal
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Streak
White
White
Porosity
Highly Porous
Highly Porous
Luster
Earthy
Dull
Compressive Strength
220.00 N/mm295.00 N/mm2
0.15
450
👆🏻
Cleavage
-
Slaty
Toughness
1.5
2.6
Specific Gravity
5.0-5.32.2-2.8
0
8.4
👆🏻
Transparency
Translucent to Opaque
Opaque
Density
-9999 g/cm32.4-2.8 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
3.20 kJ/Kg K0.39 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Bangladesh, China, India, Russia
Africa
Kenya, Morocco, South Africa, Tanzania
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Others
Greenland, Mid-Atlantic Ridge
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Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Bolivia, Brazil
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia