Definition
Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Origin
Western Australia, Minnesota
Romania and Moldova, Europe
Discoverer
Unknown
Unknown
Etymology
From its formation process
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Group
Not Applicable
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Banded, Trellis
Aphanitic to Porphyritic
Color
Red, Reddish Brown
Bluish - Grey, Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Layered, Banded, Veined and Shiny
Vesicular
Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing, Whetstones
Curbing
Construction Industry
As Dimension Stone, Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
As a touchstone, Cemetery Markers, Creating Artwork
Commemorative Tablets, Creating Artwork
Types
Algoma-type , Lake Superior-type, Superior-type and Taconite
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Features
Is one of the oldest rock
Host Rock for Lead, Is one of the oldest rock
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Not Yet Used
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.
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
Mineral Content
Hematite, Magnetite, Quartz
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Fe, Iron(III) Oxide, Silicon Dioxide
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism
Types of Weathering
Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Wind Erosion
Chemical Erosion
Grain Size
Large and Coarse Grained
Medium to Fine Coarse Grained
Fracture
Uneven, Splintery or Conchoidal
Conchoidal
Porosity
Highly Porous
Less Porous
Luster
Earthy
Subvitreous to Dull
Cleavage
Imperfect
Perfect
Toughness
1.5
Not Available
Specific Gravity
5.0-5.3
2.86-2.87
Transparency
Translucent to Opaque
Translucent
Density
Not Available
2.77-2.771 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Not Yet Found
Africa
Kenya, Morocco, South Africa, Tanzania
Not Yet Found
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
France, Greece, Romania, Scotland, Spain
Others
Greenland, Mid-Atlantic Ridge
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Bolivia, Brazil
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
New Zealand, South Australia, Western Australia