Mylonite

Pseudotachylite

Mylonite and Pseudotachylite

Mylonite

Pseudotachylite

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1 Definition

1.1 Definition

Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism

Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.

1.2 History

1.2.1 Origin

New Zealand

USA

1.2.2 Discoverer

Unknown

1.3 Etymology

From Greek mulōn mill + -ite

From pseudo- +‎ tachylite, a glassy rock generated by frictional heat within faults.

1.4 Class

Metamorphic Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Not Applicable

1.6 Other Categories

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Foliated

Quench

2.2 Color

Black to Grey

Black, Brown, Colourless, Green, Grey, Pink, White

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Dull, Banded and Foilated

Dull and Soft

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

3.1.2 Exterior Uses

As Building Stone, As Facing Stone, Paving Stone, Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

for Road Aggregate, Landscaping, Roadstone

As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Gemstone, Jewelry

Creating Artwork, Gemstone

4 Types

4.1 Types

Blastomylonites, Ultramylonites and Phyllonites

Not Available

4.2 Features

Surfaces are often shiny

Host Rock for Lead

4.3 Archaeological Significance

4.3.1 Monuments

Used

4.3.2 Famous Monuments

Data Not Available

4.3.3 Sculpture

Used

Not Yet Used

4.3.4 Famous Sculptures

Data Not Available

Not Applicable

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

Used

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

5.2 Composition

5.2.1 Mineral Content

Porphyroblasts

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

5.2.2 Compound Content

Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Not Applicable

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Not Applicable

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Sea Erosion, Wind Erosion

Not Applicable

6 Properties

6.1 Physical Properties

6.1.1 Hardness

3-47

1 7

6.1.2 Grain Size

Fine Grained

Very fine-grained

6.1.3 Fracture

Conchoidal

Uneven

6.1.4 Streak

White

Light to dark brown

6.1.5 Porosity

Highly Porous

Less Porous

6.1.6 Luster

Shiny

Vitreous

6.1.7 Compressive Strength

1.28 N/mm²60.00 N/mm²

0.15 450

6.1.8 Cleavage

Conchoidal

Irregular

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.97-3.052.46-2.86

0 8.4

6.1.11 Transparency

Opaque

Transparent to Translucent

6.1.12 Density

2.6-4.8 g/cm³2.7-2.9 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

1.50 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

China, India, Indonesia, Saudi Arabia, South Korea

South Korea

7.1.2 Africa

Eritrea, Ethiopia, Ghana, South Africa, Western Africa

Western Africa

7.1.3 Europe

England, Finland, France, Germany, Great Britain, Greece, United Kingdom

Great Britain, Switzerland

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

USA

Not Yet Found

7.2.2 South America

Not Yet Found

7.3 Deposits in Oceania Continent

7.3.1 Australia

Central Australia, Western Australia

All about Mylonite and Pseudotachylite Properties

Know all about Mylonite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Mylonite and Pseudotachylite belong to Metamorphic Rocks.Texture of Mylonite is Foliated whereas that of Pseudotachylite is Quench. Mylonite appears Dull, Banded and Foilated and Pseudotachylite appears Dull and Soft. The luster of Mylonite is shiny while that of Pseudotachylite is vitreous. Mylonite is available in black to grey colors whereas Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors. The commercial uses of Mylonite and Pseudotachylite are creating artwork, gemstone, jewelry.