Question | Answer |
what is weathering? | destructive process that will, change the rock physically or chemically. 2 types of weathering chemical and mechanical. (breakdown) |
what is erosion? | initial removal of weathered material. (removal) |
what is mechanical weathering? | Mechanical weathering is simply rock breaking due to brute force. |
what is chemical weathering? | chemical weathering is decomposition due to attack by elements in air and water. Carbonic acid in rainfall, the dominant agent of chemical weathering, |
how carbonic acid is formed and its role in solution and hydrolysis? | Carbonic acid in rainfall, Carbonic acid slowly but completely dissolves calcite/limestone, carrying away ions in solution and leaving behind holes. |
the concept of equilibrium in chemical weathering? | When things are in equilibrium they are stable and will not change if there not stable then they will change to reach that equilibrium |
what is earths crust made of? | volume 95% crystalline and surface 75% sedimentary |
what is differential weathering? | weathering at different rates, some rocks are more resistant then others. cliffs are have more resistance rock then slope rocks. |
why is weathering beneficial? | it's beneficial for soil, nutrients, ores, and sediments. but can be destructive (weathers away rock) |
3 most common ways rocks will weather? | oxidation, solution, and hydrolosis |
what are the 4 products of chemical weathering? | iron oxide (extremely stable), ions (non solids), clay (microscoppic real absorbant), quartz (not effected by chemical weathering) |
climatic effects on chemical weathering? | the dryer the weather, the more slower chemical weathering. the more weather the more faster chemical weathering |
What is the ecological significance of laterite soils? | laterite soils are signifance un the tropical climates, as it is nutrient rich and without these soils it would dry out because the a horizon underneath is very poor. |
what is frost wedging? | water flows through cracks, it freezes. melts and repeats |
what is abrasion? | rocks hitting other rocks. grinding away by friction and impact. responsible fpr chopping off sharp edges. responsible for sand |
what is hydrolosis? | chemical weathering of feldspar. loose hydrogen are destructive, it boots the cation out and takes its place. |
what is solution? | usually slow but effective process of weathering and erosion in which rocks are dissolved in water. |
what is laterite? | a reddish clayey material, hard when dry, forming a topsoil in some tropical or subtropical regions and sometimes used for building. |
what is detrital sediments? | loose, solid particles derived from weathering. They are lumped into four size categories: gravel, sand, silt, and clay. Stacked rounded grains have spaces between them. |
what is chemical sediments? | ions dissolved in solution |
what is detrital rocks? | cemented fragments of other rocks, classified by texture first. rounded grains with spaces |
what is chemical rocks? | ions precipitated from solution. interlocking grains with no spaces. classified by composition 1st. |
detrital rocks and grain sizes from largest to smallest. | gravel larger 2mm(breccia), sand (quartz sandstone) 1/16-2mm, silt (siltstone)not visible grains 1/256-1/16, clay (shale) 1/256 |
what is sedimentary structure bedding? | series of visible layers. horizontal bedding (most common), cross bedding (inclined layers inside horizontal layers), gradded vertical change in grain size |
what is sedimentary structures ripple marks? | perpendicular to the waves |
what is sedimentary structure of mud cracks? | about to dry out. water dries out |
what is sorting? | process of selection and seperation of sediment grains according to their grain size. gives us lots of clues of the ancient enviornment. |
what is rounding? | the grinding away of sharp edges and corners of rock fragments during transportation. |
what is formation? | a mappable rock unit. visible characteristics then its neighbors. naming a formation (type locality and rock type) |
what is limestone composed of? | calcite |
what is shale composed of? | mica |
what is coal composed of? | carbon |
what is chert composed of? | quartz |
how grain size and rounding change with transport? | the farther it travels the smaller the grain size and the rounder the rock, the closer it is from starting point then the bigger the grain size and sharper edges. |
energy level and rock found in alluvial fan? | high energy find conglomerate |
energy level and rock found in beach? | high energy quartz sandstone |
energy level and rock found in lagoon? | low shale micrite |
energy level and rock found in lake? | low shale |
energy level and rock found in reef? | high limestone |
energy level and rock found in deep ocean? | low chert |
high energy causes what kind of grains? | larger grains |
what is lithification? | compaction and formation of cement. |
what is granite composed of? | clay and quartz |
horizons? | O (really rich), A (really poor), B accumulation (really rich), C (weathering) |
can quartz be affected by chemical weathering? | quartz is nuetral so hydrogen cant do anything. |
how does mechanical weathering speed up chemical weathering? | Mechanical weathering speeds up chemical weathering by exposing new surfaces to elements like air and water. |
what are the sedimentary structures? | bedding, ripple marks, and mudcracks |