Fractures
Faults Joints
Joint sets
Group of joints parallel jointsHave common origin
Recognizing joints
Lack of offsetJoint surface
textures Hackle Origin Plumose Rib Marks Fringe Joints Rib
mark
Characterization of Single Joints
Surface texturesMineralizationShapeOrientationLengthAperturePath or trace
pattern
Courtesy of Zion National Park
Recognizing Joint Sets
Single joint set parallel and evenly spaced
Multiple sets form a system
Abutting relationships
Which set is youngest?
Characterization of Joint Sets
OrientationTypical joint
lengthDensity/spacingRelation among
setsLateral extent Individual joint
interactionsJoints at Arches National Park
Polygonal Joints
Cooling basalts and drying mud
‘Y’ intersections
Veins, sills and dikes
Also features with opening separation
Anti-opening cracks?
StylolitesCompaction Bands
Petit et al, JSG
Mapping Fractures
Map and analysis by Ze’ev Reches
Map relation of fractures to other structures
Joints Folds Faults Stratigraphy
Faults Folds Stratigraphy
Myers and Aydin, 2004, JSG
Gross, 1995, GSA Bull
Fractured Rock MassMoenave Fm. in Utah
3D Conceptualization
fracture
fracturetermination
Outcrop Conceptualization