[ Poll ] Geology Rocks!

What do you think of rocks?

They're pretty cool.......		9.1%	[ 4 ]
What's the big deal? They're just rocks......		13.6%	[ 6 ]
OMG ROCKS THEY ARE FREAKING AMAZING!!!!!!!!!!!!!!!!!		54.5%	[ 24 ]
Um, well, we all must survive, and rocks help us survive, so I'm cool with rocks........		6.8%	[ 3 ]
ROCK AND ROLL!!!!!!!!!!!!!!!!!!!!		15.9%	[ 7 ]

Total Votes: 44

[Kaivin]

/stares gaping at notes
Oh man.
Good luck with that.
O.o
My major is in communications so this goes like- "fwooosh" over my head.
I can hear it, actually.
The Fwoosh.
ninja

[Tsukikowerewolf]

Final test tomorrow! Wish me luck, please, everyone!!!!!!!!!



Review Notes for Geology Test on Friday

“Forsake all hope ye who enter here.” ~ J.R.R. Tolkien or the geology professor?!?!
Chapter 15 is an abomination and is therefore skipped.

Chapter 16 - Running Water - water is the most important resource on the Earth - Hydrologic Cycle - The hydrologic cycle is a summary of the circulation of Earth’s water supply - Most of the water is contained in the ocean - the sun causes evaporation - water also evaporates off of surfaces of the Earth as well, such as lakes, ponds, etc. - evaporated water precipitates (any form of getting water from the sky to the ground) - more precipitation falls on the land than in the ocean - more precipitation falls on the land than the original water that evaporated from it in the first place - run-off is what runs off of the mountains, hills, valleys, etc. and back into the ocean - water that goes into the ground is called infiltration or infiltrated water (ground-water) - used to make wheat in the mid-western United States - nonrenewable resource - Sources of Earth’s Water - 97% is stored in the oceans and 3% is stored on the surface of the Earth (Hydrosphere) - Nonocean Component - Glaciers and Groundwater, as well as Freshwater Lakes, Saline Lakes and Inland Seas, Soil Moisture, Steam Channels, and the Atmosphere - Running Water - Begins as Sheetflow - Infiltration capacity is controlled by - Intensity and duration of Rainfall - Prior wetted condition of the soil - Slope of the land - Nature of the vegetative cover - Sheetflow develops into tiny channels called rills - caused by initial erosion - Sheetflow stops - Channel Flow starts to happen - Rills form Streams - Streams form Rivers - Two types of flow determined primarily by velocity - Laminar Flow and Turbulent Flow - Laminar Flow - all particles flow parallel to each other - higher velocity causes Turbulent Flow - Factors that determine velocity - Gradient, or slope - Channel characteristics including shape, size, and roughness - Turbulent Flow increases erosion - virtually all rivers are Turbulent - Stream Flow - Discharge - the volume of water moving past a given point in a certain amount of time - cubic feet per minute - Velocity is feet per minute - Area is square feet - Multiply Velocity times Area to get Discharge - Changes from Upstream to Downstream - Profile - Cross-Sectional View of a Stream - Viewed from the head (headwaters or source) to the mouth of a stream - High Velocity/Low Area to Low Velocity/High Area - the highest velocity is in the middle of the stream - Base Level - flat area near river that indicates elevation/erosion for surrounding terrain - Sea Level is the Ultimate Base Level - Local Base Level is anything above Sea Level - Raising base level causes deposition - Lowering base level causes erosion - Erosion upstream is called Headward Erosion - it is lateral - Downcutting Erosion is vertical - V-Shaped Valleys indicate Downcutting Erosions, etc.

Erosion - three types - Headward Erosion is when the river erodes the land upstream - In steep gradient rivers, Downward Erosion occurs (Downcutting Erosions) - Lateral Erosion (eroding sideways if a stream meanders) - Running Water - Stream Erosion - lifting loosely consolidated particles by abrasion and dissolution - stronger currents lift particles more effectively - Physical (Abrasion) - individual particles are moving - Chemical (Dissolution) - it dissolves (the particles) - Transport of sediment by streams - Transported material is called the stream’s load - Types of load - dissolved load, suspended load, and bed load (heavy particles that eventually sink) - Capacity - the maximum load a stream can transport - Hjulestrom’s Diagram - Zero meters per second to A lot of meters per second - Deposition and Transportation - Transportation and Erosion - Competence - the largest grain size that can be transported - Deposition of sediment by a stream - Channel Deposits - Bars - Braided Streams - Deltas - Floodplain Deposits - Natural Levees - Oxbow Lakes - Meanders are dynamic, and very fast (takes only hundreds of years) - Natural Levees - the floodplain is the plain that floods - back-swamp (swampy region of a floodplain) - Yazoo Tributaries - Deltas - all rivers ultimately end up in the ocean - water velocity stops when the rivers meet the ocean - erosion occurs - large particles in beds on top of delta - foreset beds are sands and silts - bottomset beds are silts and clays - topset beds are sands - Stream valleys - the most common landforms on Earth’s surface - two general types of stream valleys - V-shaped Valleys (steep gradients, lots of Downcutting, etc.) - Wide Valleys (stream is near base level, low gradient, lateral erosion, etc.) - Incised Meanders and Stream Terraces - Incised Meanders - a flat, low-gradient river has lateral erosion - then it downcuts to form a V-shaped valley - caused by drop in base level or uplift in gradient - Terraces - ancient floodplains - Drainage Networks - Land area that contributes water to the stream is the drainage basin - the ridge between two streams is called a divide - Drainage Pattern - Dendritic Drainage (constant slope and homogenous rock pattern - looks like the veins in a maple leaf - maximum drainage area for minimum amount of linear foot of vein) - Radial Drainage (when rivers flow down all sides of a mountain) - Rectangular Drainage (based on joint directions) - Trellis Drainage (a series of linear mountain ranges form many small rivers going into a large river) - Formation of a water gap - A water gap is a notch where a river cuts through a ridge that lies in its path - Two possible methods of formation - Floods and Flood Control - Types of Floods - Regional Floods (extended rainfall or glacier melt) - Flash Floods (rain goes down the mountainsides) - Ice-Jam Floods (Ice breaks and releases river) - Dam failure (enough said) - Flood Control - doesn’t work, etc.

Groundwater - a nonrenewable resource - major source of water for agriculture - water found in the pores of soil and sediment, plus narrow fractures in bedrock - pores are either filled with air or water - beyond capillary fringe, there is the zone of saturation (pores completely filled with water) - the top of the zone of saturation is called the water table - Geological role of Groundwater - as an erosional agent, dissolving groundwater produces sinkholes and caverns - it is acidic (slightly) - Karst Topography - lots of sinkholes and caverns - the water eats through limestone - Distribution of groundwater - Belt of soil moisture - water held by molecular attraction on soil particles at the near-surface - Capillary Fringe is the zone between the zone of saturation and the zone of unsaturation - extends upward from the water table - groundwater is held by surface tension in tiny passages between grains of soil or sediment - Zone of aeration - same as zone of unsaturation - the water table is the upper limit of the zone of saturation - variations in the water table - depth is highly variable - varies seasonably and from year to year - shape is usually a subdued replica of the surface topography - Gaining Streams - water percolates from the ground into the stream - Losing Streams - loses water into the ground - porosity - percentage of total volume of a rock or sediment that consists of pore spaces - determines how much groundwater can be stored - variations can be considerable over short distances - shale has up to 50% porosity - sandstone has up to 30% porosity - water will flow better out of the sandstone, though - pumice can have up to 80% porosity - Permeability - the ability of a material to transmit a fluid (how much water can go through it) - the larger the grain size, the easier it is for water to flow through it - Aquitard - an impermeable layer that hinders or prevents water movement (such as clay) - Aquifer - permeable rock strata or sediment that transmits groundwater freely (such as sands and gravels) - One can get some water out of an aquitard, but not much - Aquicludes cannot have water removed from them at all - movement of groundwater - exceedingly slow (typical rate of movement is a few centimeters per day) - Energy for the movement is provided by the force of gravity - Darcy’s Law - Hydrologic Gradient = the difference in height between two points over the distance - h1-h2/d - springs - occur where the water table intersects with the surface (water comes from the ground) - caused by perched water tables - Geysers - intermittent hot springs - water erupts with great force - occur where extensive underground chambers exist, erm, something - Wells - Cone of Depression - water table is lowered in a cone-like shape due to the water being drawn out from a well - Artesian Wells - a situation in which groundwater is under pressure - layering of an aquifer between two Aquicludes - Non-free-flowing-Artesian-well is when the water will flow up but not to the surface - Free-flowing-Artesian-well is when the water flows all the way up to the surface - Subsidence - San Joaquin Valley of California - so much water is pumped out that all the water is out of the ground and the ground sinks - Saltwater Contamination is a problem near coasts and coastlines, etc.

Thanks so much, and I'll see you next semester!

< ^_^ >

~Tsukiko~

[nintako]

Heh, gotta love those geology puns....hehe cummingtonite....classic (and yes that's an actual mineral)

[M u s t a n g]

I need a recipe for stone soup, have any ideas.

[Tsukikowerewolf]

M u s t a n g

I need a recipe for stone soup, have any ideas.

*heh heh* I wouldn't recommend it. wink