Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
Marl is an unconsolidated sedimentary rock consisting of clay and lime
Discoverer
Johann Gottlob Lehmann
William Smith
Etymology
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,
From Old French marle, from Late Latin marglia
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Splintery
Earthy
Color
Black, Brown, Buff, Green, Grey, Red, Yellow
Beige, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Muddy
Rough and Dull
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Floor Tiles
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
As Building Stone, Roof Tiles
Other Architectural Uses
Curbing
Curbing
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts, Sculpture
Artifacts, Jewellery, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Pottery
Creating Artwork, Soil Conditioner
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Clay Marl ,Blue Marl, Red Marl, High Bank Marl, Shell Layer Marl, Under Shell Layer Marl, Sand Marl, Green Marl, Grey Marl and Clayey Marl
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Generally rough to touch, Is one of the oldest rock, Splintery, Very fine grained rock
Archaeological Significance
Famous Monuments
Jantar Mantar in India
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Formation
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.
Marl forms when very fine-grained clay particles are deposited in water which settles at the bottom of water bodies and are compacted by overlying sediment; the water squeezes out and hence forming Marl rock.
Mineral Content
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Calcite, Clay, Dolomite, Gypsum, Micas, Pyrite, Quartz
Compound Content
Ca, Fe, Mg, Silicon Dioxide, Sodium
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, Silicon Dioxide
Types of Metamorphism
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-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Very fine-grained
Porosity
Highly Porous
Highly Porous
Specific Gravity
2.2-2.8
2.2-2.8
Transparency
Opaque
Opaque
Density
2.4-2.8 g/cm3
2.4-2.8 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
India, Pakistan, Russia
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Ethiopia, Kenya, Morocco, South Africa
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Deposits in Western Continents
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
New South Wales, Victoria, Western Australia