Question | Answer |
what is compressive stress? | flattens boddies, perpendicular to stress. convergent boundaries |
what is sheer stress? | flattens boddies, parallel to stress. convergent boundaries mostly in the subduction zone |
how does sheer and compressive stress align minerals? | Compressive or shear stress at convergent plate boundaries causes recrystallizing minerals to align with each other to create a layered texture known as foliation |
what is contact metamorphism? | Contact metamorphism involves the heat from a magma body baking shale into hornfels, sandstone into quartzite, and limestone into marble. does not affect large areas (non foliated) result in high temperature. |
what is regional metamorphsim? | Regional metamorphism involves tectonic stress aligning minerals into foliation, producing a sequence of shale->phyllite->schist->gneiss as temperature and pressure increase. |
List in order the progressive metamorphic series? | low pressure and temperature to high. micro shale (mica) to slate (mica) to phylitte (mica) to visible schist (mica) , gneiss to migamatite to magma |
metamorphic rock of shale | hornfels mica |
metamorphic rock of sandstone | quartzite |
metamorphic rock of limestone | marble |
metamorphic rock of basalt | hornfels |
metamorphic rock of granite | gneiss |
composition of slate? | mica |
composition of marble? | calcite |
composotion of phylitte? | mica |
composition of quartzite? | quartz |
composition of schist? | mica |
composition of hornfels? | made by the contact of mudstone and shale. |
composition if gneiss? | quartz, feldspar, hornblende |
what is foliation? | its a texture, exclusive to metamorphic rocks caused by differiented pressure. |
In what type of tectonic environment are most metamorphic rocks formed? | convergent plate boundaries |
what are the degrees of folliation? | list goes lower degrees to higher degrees. slaty cleavage (splits into thin plates), schistocity (visible aligned mica), gneissic - light and dark layers (highest degree) |
factors in slope stability? | slope angle, debris thickness, vegitation, plane orientation, and gravity |
slope angle in slope stability? | steeper the slope the less stable |
debris thickness in slope stability? | thicker debris means its weaker |
vegiation in slope stability? | more vegetation more stability |
plane orientation in slope stability? | bedding, foliation, and fractures. planes of weakness tend to be horizontal. parallel unstable to hill slopes. perpendicular more stable. |
What are the common triggers? | earthquakes (most common), undercutting, heavy rainfall, weigh added to upper part of the slope. (construction) |
role of water in mass wasting. | water affects sheer strength. dryer: not very stable low ss. damp: really stable high ss, saturated: extremely unstable very low sheer strength but high sheer force. |
what is creep? | (continous process) slow process happening on all slopes. not really an event. Not dangerous but destructive. expansion and contraction |
what is toecutting? | |
what is mudflow/debrisflow? | flowing mix of debris and water, usually channelized. Carrys big objects needs lots of debris and lots of water. |
what is earthflow? | often a slump at top, mostly a blanket of vegetation flowing downhill. |
what is avalanche? | turbulent flow of debris and air. very fast, and it has a swirling flow |
what is rockfall? | result of frost wedging or toecutting. rock falling |
what is rockslide? | (block glide) bedding planes, parallel to slope break off. usually breaks up into a rock avalanche. |
what affects sheer force and sheer strength? | Changes in slope angle, debris thickness, vegetation density, plane orientation, or moisture can raise shear force or lower shear strength enough to destabilize a slope. |
what is sheer force? | is opposed by shear strength, which is how well slope materials hold together. perpendicular force towards gravity, adding weight or steepness increases sheer force. |
what is sheer strength? | its the strength of the slope. the more sheer force, the less sheer strength means the slope is unstable. the less sheer force, the more sheer strength means the slope is stable. |
name 5 ways mass wasting can be lessened during and after construction? | stitching, removal, retaining walls with drains, Terracing |
stitching | adding bolts to add stability |
removal | remove part of the slope until it is more stable |
retaining walls with drainage | drain drives water out of the slope so the water doesnt move it, and wall to hold the slope |
terracing | if there are any rock fall, terracing will prevent the rocks to cause any damage it will just land on its step. |
quick veg | vegetation adds stability to a slope. |
what is confining pressure? | most common, all rocks are experiencing this. pressure applied in all sides. |
what is differential pressure? | greater force in one direction, usually caused by tectonic force. |