Gy102 week 8 Notes
Gy102 week 8 Notes GY 102
Popular in Earth System Processes
Popular in Geography
One Day of Notes
verified elite notetaker
This 6 page Class Notes was uploaded by Elle Notetaker on Tuesday October 11, 2016. The Class Notes belongs to GY 102 at University of Alabama - Tuscaloosa taught by Mary Pitts in Fall2014. Since its upload, it has received 5 views. For similar materials see Earth System Processes in Geography at University of Alabama - Tuscaloosa.
Reviews for Gy102 week 8 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/11/16
First, I would like to apologize for going MIA for the last couple weeks. I broke my nose because life hates me, and was out of school for long enough to miss quite a bit. GY 102 week 8. 10/3/16 A map showing different types of vegetation occurring across Al is a thematic map. Mollisol is the soil order that is most agriculturally productive because it forms under grasslands. Weathering- air, water, ice. Physical weathering: Mechanical force breaking down earth material into smaller particles. It can be either large or small scale movement. Chemical weathering: chemical reactions break down earth materials. The materials react with air, water, or organic material causing their position in the rock to loosen. Both chemical and physical weathering result in much smaller particles that are easier to be picked up. Weathering facilitates erosion and makes earth materials more chemically stable at the earth’s surface. Physical weathering tends to result in earth material being broken in large, angular pieces due to the mechanical forces. It shapes the landscape. Types of Physical Weathering: Weathering due to increase in void space (open air space; sometimes after it’s rained, void space can be occupied by water. Gaps between mineral grains). Eventually the void space becomes too big for the minerals to hold the rock together. A. Freeze/Thaw or Frost shattering- rocks develop cracks that create pathways for water to enter. When the temperature falls and the water freezes and expands into ice, pushing against the rock. When the ice melts, it relaxes. This cycle eventually expands the void space until pieces break off. B. Crystal Growth: Aveolar Weathering- salt crystals grow. Water carries small fragments of dissolved minerals (ion state) the dissolved minerals get in through physical processes. Ex- calcium, sodium, can come out of the water through chemical precipitation (the opposite of the chemicals dissolving in water- they’re left behind). As the crystals grow, they create cavities in the rock body. The minerals get larger and fall out, leaving the cavity behind. C. Plant Wedging: roots exploit cracks in rock to push apart the rock material and expand cavities, loosening connections and increasing void space. D. Cycles of Wetting and Drying- some earth materials (rocks and soils especially) have clays that will expand when they get wet- these are called ‘shrink-swell clays’ and absorb water. The layers are like sheets of paper and when water gets in, it goes between the layers and they move apart. Virtisols have shrink-swell clays and develop cracks in the horizons. Outer layers of the rock come off in sheets, called spalling. Spalling can be so severe that a rock goes from angular to round, called spheroidal weathering E. Thermal Expansion causes void space to expand. Cycles of heating and cooling. When it’s heated, minerals expand, contracting when they cool. The transition disconnects mineral grains and causes them to fall off. F. Unloading/Exfoliation (mainly happens on Granite/ intrusive igneous rock.) When pressure above it goes away (after granite is pushed up or soil is scraped away by an ice sheet or something) the granite expands, causing the void space to get bigger and the outer layers to break off in large sheets. Chemical Weathering- much more detailed than physical weathering, but most types involve water. Not all minerals are equally susceptible to chemical weathering with certain materials. Some minerals are more vulnerable to water or air. Rocks frequently exposed to air and water will weather more than those that aren’t. Chemical weathering makes rounder features than physical by breaking rocks apart at the atomic level. A. Solution (dissolution, carbonation) is when water dissolves minerals. Most minerals dissolve in water (water is called the universal solvent) because water has polarity (has both + and – charge). Silica does not dissolve – makes up quartz. Silica has a robust composition that’s difficult to break up. It’s a reversible chemical reaction- Hard/soft water- the opposite reaction is called chemical precipitation and requires water to evaporate. Acidity affects water’s ability to dissolve it. Carbonic acid is comes from both decaying plant matter in soils and CO2 in the atmosphere. Rain water collects it and dissolves it as carbonic acid. Carbonic acid is the main source of acid in rain. Limestone is most prone to this weathering; it’s made of Calcium Carbonate (CaCo3)- shells that collect on the sea floor and are compressed. Dolostone and Travertine also dissolve easily. B. Hydrolysis- Hydrogen ions in water break apart from the water molecule and swap places with similar ions in soils and rocks. Loosens minerals in rocks and breaks them apart. H+ replaces cations (+ charged particles/elements). Water disassociates into H+ and OH- (hydroxyl) (an anion: a – charged particle). Ion exchange. The charge status the things switching places need to be similar. Hydrolysis & Roots: H+ from plant metabolisms switches places interacts with clay colloids/nutrients in soils. C. Hydration- can also be considered part of physical weathering, and is swelling/contraction, or wetting/drying cycles. It’s both physical and chemical. You add water to minerals and change their chemical state. Addition to water molecules on the outside of a mineral. D. Oxidation and Reduction are half reactions. You can only get oxidation reactions if something else is reduced. Oxidation is when electrons are added to minerals to make oxides. The reduction part is when something loses electrons. Reduction: Oxygen bonds (addition of electrons) to minerals to make them more chemically stable. Oxidation: Oxygen bonds (removal of electrons) to minerals to make oxides; less chemically stable. Helps horizons form in soils. http://weknowmemes.com/2012/08/the-deadly-facts-about-water/ Gy102 week8. 10/6/16 Mass Wasting Mass wasting- the instantaneous movement of earth materials down a slope. Happens to soil & weathered material and has a role in erosion. Once it is broken down, the particles have less mass and can be moved easier. The energy source is gravity and the timing can be very difficult to predict. It can be due to construction, mining processes, and gravity I. Mass wasting. A- basics. a. Instantaneous movement. Rock, soil, and regolith move; it’s a large mixture of movement. b. Factors involved: gravity- it can either facilitate or lessen the possibility of mass wasting. Triggering factors, including saturation conditions (water can lubricate and add mass to soil), shaking. If the force of gravity is stronger than the cohesion and friction, mass wasting occurs. G>(Cohesion + friction)=mass wasting. Cohesion- size/how stable the material is/how many pieces- larger rocks will stay where they are more than other rocks. Friction- rougher rocks will move less than smooth/round rocks. Water lowers friction. c. Earth materials become stable at a specific slope angle- each material has its own. The angle of repose is the steepest angle at which loose sediment is stable. Scree/talus cones are created by the angle of repose. Mass wasting B: Major types 1. Heaves: vertical movement of materials because of expansion and contraction cycles created by physical weathering processes like freeze/thaw, wetting and drying, and thermal expansion. Weathering degrades the structural integrity of the slope. Examples of Heaves are Rock Falls (fast) and Creep (slow and progressive). a. Creep: slow and progressive, caused by cycles of wet/dry, freeze/thaw, and shaking. You can’t see it really happening. Every time the material expands, the material is pushed up. When it contracts, it rolls down the hill a bit. With each contraction, the material shifts. b. Rock Fall is caused by the same things as Creep, increasing void space until rock falls of and knocks loose more. 2. Flows involve a mix of solids and liquids (some have lots of water, some don’t have much). It moves as a fast jumble of movement and is triggered by rain and increased water content. a. Debris flow has a large mixture of different sizes of debris, forming a channel called a shoot. Debris flows can even pick up houses. The debris flow scrapes out a shoot, and can lead to the formation of tributaries. b. Mud flows are common in places where ice and snow are melting, and with volcanic eruptions. Many volcanoes are tall and steep, so ice and snow form around the crater. When the volcano erupts, the ice and snow melt, run down the volcano picking up mud, and create a mud flow. A mudflow caused by a volcanic eruption is called a Lahar. c. Slides are where material slips/slides down a hill en mass (it all goes together, not being pushed by more stuff). i. Planer slide is a large block of rock breaks and slides parallel to the slope. The things on top of a planer slide retain their structural integrity. (think of it like ground surfing. With the ground.) ii. Rotational slides have both vertical and lateral (sideways) displacement when a rock swings sideways as/before it falls. Rotational slides can create spoon-shaped scars in the land. Small ones are called rotational slumps. 3. Humans as Mass Wasting Agents. Mass wasting transfers energy and sediment down hills. Natural mass wasting is not the most efficient way- people are. Humans move more sediment than any other mechanism. Hydrologic Cycle A. Characteristics: Water is important and all the water on Earth has been here since the start. Water is shifted through the ocean, land (soil, streams, plants, etc.), and the atmosphere Pic is from https://www.pinterest.com/pin/129971139217331042/ B. Surface Processes- the phase changes of water. a. Evaporation- water shifts from its liquid form to the gaseous form, entering the atmosphere i. Transpiration- plants send water straight from their leaves to the atmosphere. ii. Evapotranspiration- it’s difficult to tell what is due to plants and what is due to evaporation, so we just kind of combine them b. Precipitation- water leaves the atmosphere and returns to the earth. Snow, rain, hail, etc. c. Infiltration- water moves from the surface to the subsurface. Porosity is the amount of void space in a material, while permeability is how well the void space is connected (how easily water/air can move through soil or a rock body, involving cracks, cavities, tunnels, etc). Impervious layers are too dense to allow infiltration. d. Runoff is water that can’t infiltrate, or excess precipitation, which will collect along the surface and move in sheets, channels, etc. to enter streams (stream flow). If the infiltration rate is lower than the rainfall intensity, runoff forms (rain>infiltration). Runoff also forms when the soil just can’t hold any more water- this often happens in long duration and high intensity events. https://1d4chan.org/wiki/Rocks_fall,_everyone_dies
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'