• A kind of foliation • Deformation Fabric • Rock splits along preferred planes Lachlan fold belt, Australia Photo by E.L.Miller... Spaced cleavage Cambrian Rocks, South Verkhoyansk...
Trang 2Metamorphic Rocks Foliations, and Lineations
Trang 3• Fabrics
• Foliation, cleavage, lineation
– Cleavage and Folds
Trang 4Geothermal Gradient and
Metamorphism
Trang 5Naming of Metamorphic Rocks
Trang 6Slatey cleavage
Trang 7Gneiss
Trang 8Looks Like Bedding, but is it?
Trang 9Metamorphic layering
Broosk Range, AK
Trang 10Isoclinal Fold
Trang 11Quartz-mica schist
Trang 13Metamorphic Fabrics
• Foliation
– Cleavage – Schistosity
• Lineation
S-tectonite
Trang 14Random fabric
Foliation
Lineation
Trang 15Penetrative Fabric
Spaced Fabric
Trang 16• A kind of foliation
• Deformation Fabric
• Rock splits along preferred planes
Lachlan fold belt, Australia
Photo by E.L.Miller
Trang 17Spaced cleavage
Cambrian Rocks,
South Verkhoyansk
Trang 18The beginning of Metamorphism:
Axial Planar Cleavage
Trang 21Relationship o cleavage to
foldingAxial-planar cleavage
Trang 23Axial Planar cleavage
Trang 25SEM Image of Clays in Shale
Trang 26Pressure solution in Clay-rich
Limestone
Trang 27Early pressure-solution cleavage
in limestone
Trang 28Small quartz vein cut by a spaced crenulation/solution cleavage Documenting the extent of material removal along these surfaces Photo from David Gray, Monash University, Australia
Trang 29Sequential diagram of % shortening by folding (initially by buckling), cleavage development and dissolution
Courtesy of David Gray, Monash University, Australia
Trang 31Sandstone after compaction
Trang 32Beginning of foliation
Trang 33Crenulation Cleavage
Small scale kinks and pressure solution surfaces
Trang 34Crenulation Cleavage Beginning
Trang 35More Advanced Fabric
Trang 36Coarse Sandstone-Strong Foliation
Trang 37Two Foliations!
S2
S1
Trang 38Spaced Pressure-Solution Cleavage
Trang 39Shortening by folding vs shortening by cleavage