Different Types of Rivers correct answers 1. Dendritic (looks like a dendrite)
2.Radial (looks like lots of dendrites going into one area)
3. Rectangular
4. Trellis (looks like a tree)
What kind of drainage pattern exists around Happy Valley? correct answers -Dendritic or trellis
Measuring sediment transport correct answers Discharge=A x v
A= channel area
v= tree velocity
Which type of river geometry characterizes northern Pennsylvania correct answers Trellis
Competence correct answers A measure of the largest particle that a stream can transport
Capacity correct answers The amount of sediment that a stream can transport
How would you describe the Mississippi River at the point where it meets the Gulf of Mexico
correct answers Low competence and high capacity
Narrow Mountain Streams correct answers High competence, low capacity
Wide Meandering Streams correct answers Low Competence, high capacity
Straight Channel correct answers Maximum velocity in the center of the stream
Curved Channel correct answers Maximum Velocity is on the side
If a meandering stream scours a bank at a sharp bend, where does the sediment go correct
answers - It is deposited on an opposite side of a scoured bank
- It is transported far downstream
Seasonal Floods correct answers -Occur over regular intervals due to heavy snow or melts
-Are very dangerous
-Can be assign an annual probability--> Annual probability= 1/Recurrence Interval- if a certain
flood stage is achieved every 10 years, then annual probability = 1/10=10%
Flash Floods correct answers -Result from events that lead to rapid and often catastrophic rise in
water level
- Caused by dam collapses or isolated thunderstorms in arid regions
-Megafloods occurred when ice dams created by glaciers gave way
Sedimentary Rocks correct answers -Form from pre-existing rocks at the surface of the Earth
-Temperature and pressures are LOW
, -Can incorporate sediments from igneous, metamorphic and reworked sedimentary rocks
Clastic Sedimentary Rocks (or Detrital) correct answers Sedimentary particles are held together
by pressure and cement
Chemical Sedimentary Rocks correct answers Minerals precipitate from solution
Lithification correct answers The process by which loose and unconsolidated sediment is turned
into a rock
Which would you guess is the most important criterion for classifying clastic sedimentary rocks
correct answers - The minerals that make up the clasts
-The size of the largest clasts
-The angularity of the clasts
-The uniformity of clast size
River Deposits correct answers -Dirty Sandstones
-Clasts- sand grains
Floodplain Deposits correct answers -Shales
- Clasts: Mud
Shale Facts correct answers - Shales the the most abundant of the clastic sedimentary rocks
-Form from finest particles transported far from source rock
1. Floodplains of rivers
2. Lake Beds
3. Ocean Bottom
- Color ranges from black (organics) to green (clays) to red (hematite)
The sedimentary rocks of Ordovician age (450 Ma) in southeastern PA are congomerates.
Ordovician rocks in central PA are sandstones and shales. What does this imply correct answers
During the Ordovician, mountains were located in southeastern PA and central PA was flatter
Chemical Sedimentary Rocks correct answers -Form when minerals precipitate from water
solutions (precipitation= crystallization)
- Typically form when water solutions are supersaturated with respect to the mineral
-Causes of supersaturation
Loss of water from evaporation- Evaporites
Biological pumping of mineral components into solution to make shells- Limestone
Which of the following processes is least important in te lithification of loose sediment correct
answers Increased weathering of sediment particles
If State College is underlain by limestones that are 450 million years old, what might you
surmise about this area at that time correct answers -State College lay beneath a shallow sea
- State College was located near the equator