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Columnar joints in basalt, along the Deschutes River, Oregon

Columnar joints in basalt, along the Deschutes River, Oregon. These are part of the Columbia River Basalt Group. Photo by Vince Cronin.


Terms that are particularly important for you to understand



Strain terms

angular shear anisotropic (anisotropy) area strain biaxial strain coaxial strain
contraction deformation displacement vector distortion elongation
extension finite strain heterogeneous homogeneous infinitesimal strain
instantaneous strain internal rotation isotropic (isotropy) linear anisotropy major axis
minor axis non-coaxial strain planar anisotropy plane strain principal plane of strain
principal strain principal strain axis pure shear rotation shear strain
simple shear strain ellipse strain ellipsoid stretch subsimple shear
translation triaxial strain uniaxial strain volumetric strain

Stress terms

body force deviatoric stress differential stress intermediate principal stress (σ2)
maximum (or greatest) principal stress (σ1) mean stress mega-Pascal minimum (or least) principal stress (σ3)
Mohr circle Mohr diagram Newton (kg m/s2) normal stress
Pascal (Newton/m2) pressure principal plane principal stress
principal stress axis shear stress stress stress ellipsoid
stress tensor surface force (or traction) total stress

Rheology and mechanics of materials

bulk modulus elastic-plastic permanent strain shear modulus viscoelastic (Kelvin)
constitutive equations Hooke's law plastic steady state viscoelastic (Maxwell)
elastic linear elastic Poisson's ratio strain hardening visco-plastic
elastic perfectly plastic perfect elastic recoverable strain strain rate viscous
elastic with hysteresis perfectly plastic rheology strain softening Young's modulus

Brittle failure

arrest line cataclasis cataclastic conjugate joint set crack face
crack tip critical crack growth en echelon array fault fault tip
hackles mixed mode crack mode I crack mode II crack mode III crack
nucleation point opening mode crack orthogonal joint set plume shearing mode crack
shear shear striation slickenfiber slickenside subcritical crack growth
tearing mode crack tip line twist hackle -- --

Faults and faulting

back thrust balanced cross section basement blind thrust cover sequence
damage zone decollement (reverse fault) detachment (normal fault) dip slip duplex
fault fault-bend fold fault core fault-propagation fold fenster
flat floor thrust flower structure foreland gouge
graben half graben high-angle reverse fault hinterland horse
horst imbricate fan klippe lateral ramp left-lateral
listric low-angle (normal) fault mylonite net slip normal fault
piercing point piggy-back basin pop-up pull-apart basin ramp
ramp anticline releasing bend restraining bend reverse fault right-lateral
roll-over roof thrust separation shear slickenfiber
shear striae slickenside slip sole thrust strike slip
thrust fault tip line transcurrent fault transfer fault transform fault

Folds

antiform nose of a fold ptygmatic fold Rich-model anticline doubly-plunging fold
synform limb similar fold fault-bend fold overturned limb
homocline crest point, curve, surface chevron fold fault-propagation fold overturned fold
monocline culmination kink fold roll-over aspect ratio
anticline trough point, curve, surface box fold buckle inter-limb angle
syncline depression harmonic fold bend fold tightness
structural dome conical fold disharmony fold flexural fold gentle fold
structural basin differential compaction folding parasitic fold flexural-flow fold open fold
fold train median surface M-fold passive fold closed fold
facing direction enveloping surface S-surface drape fold tight fold
vergence wavelength Z-fold upright fold isoclinal fold
inflection point, curve, surface initial wavelength drag fold inclined fold dip isogon
hinge point, curve, surface amplitude symmetric fold recumbent fold fold order
axial point, curve, surface isoclinal fold asymmetric fold plunging fold fold superposition
cylindrical fold parallel fold supratenuous fold vertical fold fold interference
closure concentric fold ramp anticline horizontal fold --

In addition to your textbook, the best source for current definitions for all geological terms is the American Geosciences Institute's Glossary of Geology, which you should have a copy of if you are serious about being a geologist.

Klaus K.E. Neuendorf, James P. Mehl, Jr., and Julia A. Jackson [editors], 2011, Glossary of Geology Fifth Edition [revised]: American Geosciences Institute, 800 p., ISBN 978-0-922152-89-6

Available at Amazon.com and other online vendors, or directly through AGI
http://www.agiweb.org/pubs/pubdetail.html?item=300156


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