Deform & Mount Build Word Scramble
|
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Term | Definition |
Deformation | Changes in the shape and volume of rock as a result of dynamic forces within the Earth. |
Deformation occurs during: | Pluton Emplacement Volcanism Metamorphism Continental accretion |
Evidence of Deformation: | Seismic Activity Volcanism Plate Movement Mountain evolution |
Deformation occur where: | Convergent, Divergent, and Transform boundaries |
Stress | Force applied to a given area (usually expressed as kilograms per square centimeter) |
Strain | The resulting modification of a substance as a result of applied stress (unitless - length difference/time) |
Compression | Stress resulting from objects being pulled squeezed together; shortening of objects |
Tension | Stress resulting from objects being pulled apart; Lengthening and thinking of objects |
Shear | Stress resulting form forces acting parallel to one another; displacement of objects |
Tension | Stress resulting from objects being pulled apart; Lengthening and thinking of objects |
Elastic Strain | A deformed substance returns to its original state once stress is removed |
Plastic Strain | Folding or fracturing of rocks as a result of applied stress, where substances behave as ductile or brittle materials |
Factors that determine strain: | Type of strain Pressure & Temperature Rock composition Duration of stress |
Principle of Original Horizontality | Nicholas Steno; Sediments accumulate in horizontal or nearly horizontal layers |
Strike | the direction of a line formed by the intersection of a horizontal plane and an inclined plane |
Dip | the measure of an inclined plane’s deviation from the horizontal, which is measured at right angles to strike direction; maxiumum angle of an inclined plane |
Anticlines | an up-arched or convex upward fold with the oldest rock layers in its core; on either side of the crest, layers dip away from the middle - looks like an A |
Synclines | Downward arching folds with a "U"shape; the limbs on either side dip towards the crest; the youngest layers in the core |
Anticlines/Synclines | Form together from a compressional stress deforming layers in a ductile manner in the Earth |
Upright Folds | the axial plane is vertical and both fold limbs dip at the same angle; appear as linear series of repeating beds in map view |
Plunging Folds | fold axis is not vertical, but is inclined and appears to dip beneath adjacent rocks |
Domes and Basins | appear as concentric structures that warp either upward or downward; domes are older in the middle, basins are younger in the middle |
Boudinage Folds | "Sausage" looking folds generated by tensional stress deforming materials in a ductile nature; a series of either connected or unconnected necks |
Geological Structures: Brittle | When rocks are exposed to stress at shallow depths, they are subjected to brittle deformation |
Joints | Linear fractures along which no movement has taken place; almost all near-surface rocks have joints, which usually correlate with regional geologic structures |
Faults | Rocks are considered faulted when they undergo brittle deformation and there is relative movement of the rocks on either side of the fracture plane; classified based on the relative movement of the hanging wall |
Dip Slip Faults | Relative movement is in the direction of dip |
Normal Fault | The hanging wall moves down relative tot eh foot wall, the rocks move with gravity (Tensional) |
Reverse Fault | The hanging wall moves up relative to the foot wall, the rocks moves against gravity (Compressional) |
Thrust Fault | Subset of reverse fault where the angle of the fault plane is less than 45 degrees |
Strike-Slip Fault | Blocks on opposite sides of the fault side past each other; synonymous with transform faults in spreading zones |
Right-lateral Strike-Slip Fault | Plate on opposite side of the fault moves to the right |
Left-Lateral Strike-Slip Fault | Plate opposite side of the fault moves to the left |
Oblique-Slip Fault | Contains components of Dip-Slip and Strike-slip |
Tensional Stress | Ductile Strain: Boudinage Brittle Strain: Normal Faults |
Compressional Stress | Ductile Strain: Anticlines/synclines Brittle Strain: Reverse/Thrust Faults |
Shear Stress | Ductile Strain: Rotational effects (mylonitic textures) Brittle Strain: Strike-slip faults |
Mountain | An area of land that stands significantly higher; at least 300m, than the surrounding country and has a restricted summit area; a single, isolated peak |
Mountain Range | Linear associations of peaks and ridges |
Mountain Systems | Complex linear zone of deformation and crustal thickening, composed of several or many mountain ranges. |
Weathering | Differential weathering and erosion that produces topographic highs with adjacent lowlands; |
Mesa and Butte | most are less than 300m tall and not true mountains |
Block-Faulting (Tension stress) | Created by tectonic deformation where tension forces produce normal faults and regions down-dropped leaving topographic highs; Horst and Graben structures |
Volcanism | Accretion of topographic highs by the continued eruption and crystrallization of magma; Volcanoes, mid-ocean ridges, etc. |
Orogeny | Mountain building that involves crustal thickening; most occur along convergent boundaries where one plate is subducted beneath another or where two continents collide. |
Accompaniment and Formations of Oroginies | Emplacement of batholiths, metamorphism, and thickening of the Earth's crust; sedimentary rocks that formed in marine environments are often found emplaced high in mountains as a result of orogeny |
Oceanic-Oceanic Plate Orogeny | Characterized by deformation, igenous activity, and volcanic island arcs; accretionary wedges develop as sediments are folded and thrust over plates; 2 parallel organic belts develop, which eventually converge |
Oceanic-Continental Plate Orogeny | Subduction of oceanic lithosphere along an oceanic-continental plate boundary; characterized by deformation, plutonism and volcanism |
Continental-Continental Plate Orogeny | Collision of two continental plates; characterized by deformation, plutonism, volcanism, intense crustal thickening, thrusting and uplift |
Isostacy via buoyancy | An object that has an average density less than the material in which it resides will float |
Archimedes Principle | The object will displace an amount of that material equal to the weight of the object |
Post Glacial Rebound | Glacial depressions shallow as a result of glacial melt |
Glacial Maxiumum | 20,000 years ago; ice was as thick as 3km covered areas and depressed the land |
Crust | Less dense than the mantle, floats upon the mantle |
Created by:
FaithRaquel2015
Popular Science sets