Details Title: Exam 3 Description: Deformation (3/23) Total Flash Cards: 24 Created: 03/30/2009 17:28:31		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Geology Flashcards
Cards in this set: Term Structural Geology Definition -study of faulting and folding of rocks (effects of deformation) Term Faulting & Folding Definition -geolgoic structures of rocks Term Stress Definition -magnitude & direction of defroming force on surface -force applied over an area (force per unit area) Term Confining (Uniform Stress) Definition -applied by weight of overlying rocks -equal in all directions by pressure -still looks the same in layers -body to change size not shape Term Tensional (differental stress) Definition -stress on body that causes stretching and elongation -pulling apart -rocks change shape -streach & thinning faulting (stress not equal in all directions) Term Compressional (differental stress)   Definition -stress that squeezes and compresses body -pushes it together -rocks change shape -folding or faulting (stress not equal in all directions) plate tectonics= subduction Term Shear (differental stress)   Definition -force on body causing slippage or translation -one direction on top/ opposite direction on buttom -rock change shape -shearing & faulting (stress not equal in all directions) plate tectonics-transform Term Strain Definition measure of changes in -length -volume -shape in a stressed material -observable deformation in the rock Term Elastic Deformation Definition -reversible change in change (volume or shape) in rock -springs back to orginal form -nonpermanent (ex. rubberband) Term Elastic Limit Definition -limiting stress -solid has permentant deformation -does not return to orginal size or shape once stressed is removed Term Ductile Deformation Definition -undergoes smooth, plastic deformation -permentally deform -flow, no breakage -irreversable change in shape and/or volume -stress beyond elastic limit (butter-bends) Term Fracture Deformation Definition -limits of both elastic and ductile has exceeded -Brittle substance -irreversible kind of deformation (chalk-broke) Term Temperature Definition higher temp -increase ductility & less brittle solid becomes  lower temp   Term Confining Stress Definition -uniform squeezing of rock, by overlaying strata -reduction of brittleness High Confining Pressure -rocks experience ductile deformation=bend and flowing   Term Time and Strain Rate Definition -rate a rock is forced to change volume or shape -measured in volume per unit or second -fracture or ductile Term Rock Composition   Definition  minerals make up rocks properties -quartz, garnet, olivine=brittle (fracture easily) -mica, clay, calcite,gypsum=ductile (flow easily) Water content -reduces brittle, enchances ductile -weakens chemical bonds Term Lithosphere Deformation Definition Above 15km rocks are strong=fracture Below 15km rocks are fractures less common=increasing ductile (bc quartz weakens)   Term fault Definition -a fracture in a rock along which movenment occurs Term Strike Definition -bearing line definded by intersection of the plane and the horzontal (waterline marks strike) Term Dip Definition -acute angle btw plane and horizontal -perpinducular to strike Term Deformation Definition changes in  -shape -position -orientation of a body Term Brittle Deformation Definition fault: result of rapidly applied high stress which "break the rock" Term Brittle Failure Definition -subjected to great stress that exceeds the yield point  (elastic limit) -subjected to sudden stress  (impact   Term Plastic deformation Definition -does not spring back -keeps deformed shape -chewing gum -causes- high temp (near melting or high pressure)