lutite

shale

mud rocks

Potter, Maynard and Pryor; 1980; Sedimentology of Shale: Springer-Verlag, New York, 310p.

Lundegard & Samuels; 1980; Field Classification of Fine Grained Sedimentary Rocks: J Sed. Pet., v50#3, p781-786.

lamination

• color
• grain
• fabric

causes of stratification & parting in lutites

• physicochemical
• bio-organic
• burial diagenesis

fissility

• papery
• platy
• flaggy/slabby
• massive

silt content

• <1/3 silt
• 1/3-2/3 silt
• >2/3 silt
• sandy

flocculate

"average" mud rock:

• clays 61%
• SiO2 31%
• feldspar 4-5%
• CO3 3-4%
• organics ±1-2.2%
• iron oxides <1%

mineral composition

• clays
• bentonite

  tonsteins

  marker beds/time lines

  compaction

• quartz
• pyrite
• organics

environments

• euxenic
• anaerobic <0.1ml O₂/liter
• dysaerobic 0.1 - 1 ml O₂/liter
• aerobic >1ml O₂/liter

color

color variables

• organic input rate
• oxygen
• sedimentation rate

mud rock structures

lamination

• persistent distinct beds
• broken distinct beds
• wavy bedding
• curved bedding

energy and bedding type

persistent distinct - broken distinct - wavy bedding - curved bedding

varves

raindrop imprint

Some Famous Shales

• Figtree Fm
• Green River Fm
• Burgess Shale
• Borden Siltstone
• New Albany Shale & Chattanooga Shale
• Mowry & Pierre Shales
• Pennsylvanian cyclothem shales

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