Banded iron formation

Dacite

Banded iron formation and Dacite

Banded iron formation

Dacite

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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

History

Origin

Western Australia, Minnesota

Romania and Moldova, Europe

Discoverer

Johann Gottlob Lehmann

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

Family

Group

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered, Banded, Veined and Shiny

Vesicular

Uses

Architecture

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

Industry

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

Antiquity Uses

Artifacts

Other Uses

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

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

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.

Composition

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Chemical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

5.5-62-2.25

1 7

👆🏻

Grain Size

Large and Coarse Grained

Medium to Fine Coarse Grained

Fracture

Uneven, Splintery or Conchoidal

Conchoidal

Streak

White

Porosity

Highly Porous

Less Porous

Luster

Earthy

Subvitreous to Dull

Compressive Strength

220.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.5

Specific Gravity

5.0-5.32.86-2.87

0 8.4

👆🏻

Transparency

Translucent to Opaque

Translucent

Density

-9999 g/cm³2.77-2.771 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

Reserves

Deposits in Eastern Continents

Asia

China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

Kenya, Morocco, South Africa, Tanzania

Europe

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

France, Greece, Romania, Scotland, Spain

Others

Greenland, Mid-Atlantic Ridge

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

All about Banded iron formation and Dacite Properties

Know all about Banded iron formation and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Banded iron formation belongs to Sedimentary Rocks while Dacite belongs to Igneous Rocks.Texture of Banded iron formation is Banded, Trellis whereas that of Dacite is Aphanitic to Porphyritic. Banded iron formation appears Layered, Banded, Veined and Shiny and Dacite appears Vesicular. The luster of Banded iron formation is earthy while that of Dacite is subvitreous to dull. Banded iron formation is available in red, reddish brown colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Banded iron formation are as a touchstone, cemetery markers, creating artwork and that of Dacite are commemorative tablets, creating artwork.