Geology 3120 - Rock FabricGeology 3120 - Rock Fabric

ObjectivesObjectives

• Attitudes of FabricAttitudes of Fabric• CleavageCleavage• LineationsLineations• FoliationsFoliations

FabricsFabrics

FabricsFabrics

FabricsFabrics

FabricsFabrics

CleavageCleavage

• General definition - closely-spaced, aligned, planar to General definition - closely-spaced, aligned, planar to

curviplanar penetrative surfacescurviplanar penetrative surfaces

• ContinuousContinuous verses verses disjunctivedisjunctive cleavage - planar verses cleavage - planar verses

non-planarnon-planar

• Mechanical realignment and growth of clay mineralsMechanical realignment and growth of clay minerals

• Pressure dissolution processPressure dissolution process

Slaty CleavageSlaty Cleavage

Mechanical alignment and growth of clay mineralsMechanical alignment and growth of clay minerals

Slaty CleavageSlaty Cleavage

Where is the bedding?Where is the bedding?

Slaty CleavageSlaty Cleavage

Where is the cleavage?Where is the cleavage?

Slaty CleavageSlaty Cleavage

What direction is the nearest anticline?What direction is the nearest anticline?

Pressure Dissolution CleavagePressure Dissolution Cleavage

Extensional veins shortened in silt

Axial Planar CleavageAxial Planar Cleavage

Identify the folds

Axial Planar CleavageAxial Planar Cleavage

Identify the cleavage

Axial Planar CleavageAxial Planar Cleavage

Identify the axial surfaces

Axial Planar CleavageAxial Planar Cleavage

Axial Planar CleavageAxial Planar Cleavage

BeddingBedding

Axial Planar CleavageAxial Planar Cleavage

Axial SurfacesAxial Surfaces

Cleavage VergenceCleavage Vergence

WestCentral East

Cleavage VergenceCleavage Vergence

West Central East

Cleavage VergenceCleavage Vergence

WestCentralCentral

East

Cleavage VergenceCleavage Vergence

WestCentralCentral

East

Pressure Solution Cleavage - Pressure Solution Cleavage - LimestoneLimestone

Insoluble material is typically contained in the stylolite

Introduction to LineationsIntroduction to Lineations

One-Dimensional Features One-Dimensional Features

Slickenline lineationsSlickenline lineations

Fault groovesFault grooves

Stretched conglomeratesStretched conglomerates

BoudinsBoudins

Slickenline LineationsSlickenline Lineations

Calcite mineral growth

on a fault plane

GroovesGrooves

Grooves are parallel to strikeGrooves are parallel to strike

What type of fault is this?What type of fault is this?

Stretched ConglomeratesStretched Conglomerates

Rock has a foliation, lineation depends on whether clasts areRock has a foliation, lineation depends on whether clasts are

disc- or rod-shapeddisc- or rod-shaped

Boudins Boudins

Introduction to FoliationsIntroduction to Foliations

Bring in the next dimensionBring in the next dimension

Deformation or organization of grains with respect to Deformation or organization of grains with respect to

a two-dimensional surfacea two-dimensional surface

Foliations in addition to lineations may yield Foliations in addition to lineations may yield

information about the stretching direction information about the stretching direction

Foliations with LineationsFoliations with Lineations

ReferencesReferencesSlides 3 - 6: Slides 3 - 6: http://earth.leeds.ac.uk/minor/ductile/describing/lin-plane.htm

Slide 1, 8 - 11: Slide 1, 8 - 11: http://earth.leeds.ac.uk/minor/cleavage/slatey.htm

Slide 12Slide 12: : http://earth.leeds.ac.uk/minor/dmt/psolncleav.htm

Slides 13 - 16: Slides 13 - 16: http://earth.leeds.ac.uk/folds/describing/cleavage/cleavage.htm

Slide 17 - 20Slide 17 - 20: http://earth.leeds.ac.uk/folds/describing/cleavage/cleaverge.htm: http://earth.leeds.ac.uk/folds/describing/cleavage/cleaverge.htm

Slide 21Slide 21: http://earth.leeds.ac.uk/minor/dmt/stilolite.htm: http://earth.leeds.ac.uk/minor/dmt/stilolite.htm

Slide 23Slide 23: http://earth.leeds.ac.uk/minor/faults/strifibres.htm: http://earth.leeds.ac.uk/minor/faults/strifibres.htm

Slide 24Slide 24: http://earth.leeds.ac.uk/minor/faults/grooves.htm: http://earth.leeds.ac.uk/minor/faults/grooves.htm

Slide 25Slide 25: http://earth.leeds.ac.uk/minor/ductile/vasgo/congs.htm: http://earth.leeds.ac.uk/minor/ductile/vasgo/congs.htm

Slide 26Slide 26: http://earth.leeds.ac.uk/minor/extend/boudyke.htm: http://earth.leeds.ac.uk/minor/extend/boudyke.htm

Slide 26Slide 26: http://earth.leeds.ac.uk/strain/gallery/boudin.html: http://earth.leeds.ac.uk/strain/gallery/boudin.html

Slide 28:Slide 28: http://earth.leeds.ac.uk/minor/ductile/vasgo/myllin.htm http://earth.leeds.ac.uk/minor/ductile/vasgo/myllin.htm

Slide 29:Slide 29: http://earth.leeds.ac.uk/minor/ductile/gallery/plattgen.htm http://earth.leeds.ac.uk/minor/ductile/gallery/plattgen.htm