| Term | Definition |
|---|
| agents of weathering | water, wind, ice, and gravity |
| physical(mechanical) weathering | causes disintegration of earth materials |
| forms of physical weathering | 1. abraison, 2. contraction/expansion- due to changes in temp., 3. ice wedging- water that enters fractures in rocks freezes overnight and the increase in h2o volume and opening/closing of rock fracture slowly causes rock fatigue(failure), 4. frost heaving- occurs in REGOLITH, water underground freezes lifting the earth and when it melts the h20 takes grains down slope with it, 5. spheriodal weathering/exfoliation- weathering first at corners to edges then center of block forming a sphere, 6. biological activity- plant/animal activity churning up subsurface allowing o2 and h2o to penetrate surface |
| forms of chemical weathering | 1. solution- materials are dissolved in water ex. NaCl --> Na + Cl, 2. oxidation- materials are oxidized/exposed to o2 ex. FeO + O2 --> Fe2O3. 3. hydration- carbon dioxide reacts with the material |
| composition of granite | 40% quartz, 50% orthoclase, 10% ferromagnesian silicates |
| chemically-immature sediment | contains quartz, orthoclase, albite, hornblende, biotite |
| chemically-mature sediment | only contains quartz |
| physically-immature sediment | contains grains that are angular and poorly sorted |
| physically-mature sediment | contains rounded grains that are well sorted |
| SOILS | ROCK WEATHERED IN PLACE PLUS ORGANICS |
| typical soil profile in piedmont, va | topsoil, sub soil, saprolite, unweathered bedrock |
| topsoil | consists of an organic mat(humus) FOLLOWED by a zone of leaching (for chemicals) and eluviation(clays) (major filtering systems) |
| subsoil | a layer of soil beneath the topsoil that has lower organic content and higher concentrations of fine mineral particles; often contains soluble compounds and clay particles carried down by percolating water; ZONE OF ACCUMULATION |
| saprolite | a deposit of clay and disintegrating rock that is found in its original place, rock structure bt crumbles if stepped on |
| all layers above unweathered bedrock | REGOLITH |
| pedalfers | soils that form in EASTERN north america, has lots of rainfall, rich in Al and Fe, red-redbrown-brown, rich in organics, acidic |
| pedocals | soils form in WESTERN north america, calcium and carbon rich soils, gray-tan-white, poor organics, alkaline |
| factors in the formation of soils | parent material, climate, topographic position, biological activity, time |
| sediments = clastics = detritus | particles of other rocks that have been eroded from one place, transported to another, and deposited there |
| sediment sizes | clay- smallest, silt- small, sand- larger, gravels- largest |
| clay + silt = | MUD! |
| lithification | converts sediment into rock. Compaction caused by pressure generated from weight of overlying sediment. Cementation is binding of sediment by mineral agents. Common cementing agents hematite, limonite, calcite and silica |
| clastic sedimentary rocks | Sedimentary rock that forms when fragments of preexisting rocks are compacted or cemented together. EX. clay - shale, silt - siltstone, sand - sandstone, rounded gravel - conglomerate, angular gravel - breccia |
| chemical non-clastic sedimentary rocks | evaporites: form from the evap. or sea water (rock salt, rock gypsum), chert: forms from the deposition of silica in water, limestone: |
| biochemical non-clastic sedimentary rocks | A. biochemical depositions of calcite by organisms that take in sea water through life processes and extract the calcium carbonate thus secreting it as an exoskeleton, their shells are either compacted or lithified(cemented together) creating chalk, coral, copuina. B. COAL- compaction of plant materials from freshwater swamp (stages: peat-lignite-bituminous coal-anthracite coal*metamorphic*) |
| characteristics of sedimentary rocks | layering, fossils, mudcracks, ripple marks, cross bedding, rain-drop imprints, sphericals masses |
| mud cracks | form in clays and are preserved at shales; may also be found in siltstones and limy shales. |
| ripple marks | asymmetrical ripples are formed by WIND AND WATER that form in sands, symmetrical ripples are formed by WATER ONLY in sands produced by back and forth motion of water |
| cross bedding | A sedimentary rock texture characterized by overlapping and cross-cutting bedding at an angle to the main layers of bedding. topset of beds is deposited at an angle to the forset beds |
| graded bedding | A bed that formed horizontal or nearly horizontal layers at the time of deposition, in which the coarsest particles are concentrated at the bottom and grade gradually upward into fine silt. |
| rain-drop imprints | form in clays and silts by heavy but few drops that are then covered and preserved in shales and siltstones |
| mineral/energy resources are.. | finite, exhaustible, nonrenewable |
| finite | limited, metals and other oils |
| exhaustable | CAN BE USED UP |
| nonrenewable | something that once its gone ITS GONE |
| Mineral and Energy Resources: Igneous Rock | crystal settling/magamatic segregation, hydrothermal injection, pegmatites, building materials |
Combine with other sets
Share on Facebook
Share on MySpace