Wpr2 Flashcards
Oceanic crust. Magmas with low amounts of silica. Dark colored magnesium and iron rich materials.
Mafic
Formed by cooling and solidification of molten rock. “Welding of tiny pieces of solid volcanic rock.
Igneous
Continental crust. Magmas with large amounts of silica. Light colored silicate materials such as quartz and feldspar. Low densities and melting temps.
Felsic
Formed through the accumulation of sediment. Consolidated through compression and cementation. Characteristic= stratification.
Sedimentary
Formed by exposing igneous or sedimentary rock to high pressure and temp. Causes a change in mineral structure, composition and rock texture.
Metamorphic
Magmas cools below surface. Slower cooling process. Coarse grained, large crystals/minerals. Granite(felsic) Gabbro(mafic)
Igneous intrusive
Lava cools above surface, faster cooling. Fine grained, small crystals. Basalt (mafic) obsidian (felsic)
Igneous extrusive
Sediments of other rocks are compacted and cemented, layered. Sandstone and shale.
Sedimentary Detrital
Solids precipitate out of solution. Soluble. Limestone, travertine.
Sedimentary chemical
Sedimentary and igneous rocks exposed to heat and uneven pressure. Minerals align: bands wavy structure. Gneiss, slate.
Metamorphic foliated
Even pressure. Large crystal growth, 1 mineral dominates. Marble, quartz
Metamorphic non-foliated
Wearing down or destructive processes which decreases relief.
Denudation
Mid ocean ridges formed by currents of magma rising up from mantle. This creates new basaltic ocean floor that spreads away laterally from ridge and creates me crust. Older oceanic crust is subducted back into the crust and recycled.
Sea floor spreading
Plutonic, form from the cooling of magma below the surface.
Intrusive
Volcanic, form from the cooling of lava or the bonding of pyroclastic materials on the surface.
Extrusive
Organically accumulated sedimentary rocks. Formed by the remains of dead plant material.
Sedimentary organic
Plates diverge, magma wells up in the opening between plates. Constructive because material is being added to the crust. Represented by mid ocean ridge.
Divergent boundary
Plates collide. Destructive because the result in removal of or compression of the surface crust. Responsible for major mountain ranges,volcanoes and oceanic trenches.
Convergent boundaries
Tow plates slip past one another laterally. Neither create or destroy crust. Associated with seismic activity, producing shallow focus earthquakes. Most are along mid ocean ridge system
Transform boundary
Occurs at plate boundaries (causer of earthquakes)
Seismicity
Result when magma rises to the earths surface. Occurs when tectonic plates are subducted. Convergent or divergent plate boundaries
Volcanoes
Large, steeply sided volcanoes. Explosive eruptions. Vicious lava. Felsic.
Composite volcano
Gentle, nonexplosive eruptions. Low viscous lava. Mafic
Shield
Steeper than composite volcanoes, intermediate volatile contents. Mafic. Reddish- brown pyroclastic debris.
Cinder
Steep sided structures that form at the summit of a volcano, on its flanks, or as independent volcanic centers. Viscous lava that piled around the vent. Felsic.
Dome
Process at oceanic trenches where lithosphere descends into asthenosphere. New sea floor is created for the seafloor lost in this process.
Subduction
Explains the existence of hotspots. Example: Hawaiian islands lie far from tectonic plate boundaries, but still show volcanism.
Mantle plume
Molten mineral material. On earths surface called lava. Contains phosphorus, potassium, calcium, magnesium and sulfur required for plant growth.
Magma
High silica, high viscosity, trapped gas
Felsic volcano
Low silica, low viscosity
Mafic
A simple symmetrical unfold in rock structure. HILL
Anticlines
A simple downfold in rock structure. VALLEY
Synclines
Breaking down of rock into smaller components by atmosphere and biotic agencies. Mechanical chemical and biological.
Weathering
Short distance downslope movement of broken rock under the direct influence of gravity.
Mass wasting
Removal, transportation, and eventual deposition of fragmented rock over wider areas. Greater distances.
Erosion
Physical disintegration of rock material without changes to chemical composition (wedging, salt wedging, exfoliation)
Mechanical
The composition of rock by the chemical alteration of its minerals. Better in humid regions and high temps. (Oxidation, carbonation, hydrolysis)
Chemical weathering
Weathering involving living organisms
Biological weathering
Rockfall in mountainous areas, pieces of unsourced, angular rock that fall are called talus or scree.
Fall
Landslides carry large masses of rock and soil down slope abruptly.instantaneous collapse of slope and movement along a generally flare sliding plane. Initiated by rain, earthquakes and lateral erosion of streams.
Slides
Slope failure in which the rock moves downward and at the same time rotates outward along a curved slide plane that has its concave side facing upward
Slump
A section of a slope. Unstable due to the addition of water, flows downhill, may be rapid or gradual l the center of the mass moves faster than the base and sides.
Flow
Slowest and least perceptible form; very gradual downhill movement of soil can only be recognized by indirect evidence; usually the entire slope is involved. Occurs on all slope surfaces, accelerated by water
Creep
Largest particle a stream can carry
Competence
Amount of solid material a stream has the potential to transport.
Capacity
The placement of material that has been moved from another location.
Deposition
Winding channel. Usually high gradient. Mountains valleys or other relatively uniform geographic structure. Faster water than meandering but not as curving.
Sinuous
Serpentine. Low gradient flare land. Continuous process of deposition and erosion. Most rock transported are fine grained suspended load. Fastest part of water on outside (crating cutbacks)
Meandering
Multiplicity of interwoven and interconnected channels separated by low bars or islands of sand, gravel and other loose debris. Takes place when very flat stream channel has heavy load of sediment
Braided
Formed when meandering stream flows across wide nearly flat valley floor. Produces rapid and sometimes abrupt changes in the channel.
Flood plain
Caused by deposition of alluvium on the inside of bends
Point bar
Occur when the neck of a meander is cut through by the stream
Oxbow lake
When an oxbow lake dries up this is left
Oxbow scar
Erosion occurs in the outside of the meander bend where the water flow is fastest, forming the cut bank
Cut banks
Mouth of a river
Delta
% of total volume of the material that consists of voids (pore spaces or cracks) that can be filled with water
Porosity
The ability to transmit underground water. Determined by th size of pores and by their degree of interconnectedness
Permeability
Lowering of the water table around a well. Size increases with withdrawal rate.
Cone of depression
Removal of bedrock through chemical action of water.
Dissolution
Topography developed as a consequence of subsurface solution. Special landform that develop on exceptionally solvable rocks.
Karst
Where ground water is stored. Confined vs unconfined. Permeable rock layer can transmit and supply water.
Aquifers
Impermeable rock layer that prevents water movement
Aquicludes
Top of saturated zone
Water table
Removal of bedrock through the chemical action of water
Dissolution
Why are mechanical weathering processes more common in arid regions
Thin or absent veering of soil and regolith exposes bedrock to weathering and erosion
Landforms are produced largely by _______ in deserts
Water
Creates steep, rugged, rocky surfaces. During rain bed rock is mechanically weathered and eroded by running water. Erosion by rain splash, sheet wash,rilling,and stream flow. Rapid and effective.
Fluvial erosion
