Module 9 and 10

What causes uplift

-Thickening of the crust through compression

Braided

-can be high gradient -high sediment load , variable discharge multiple channels Seperated by sand gravel bars

What causes subsidence

-thinning of crust result in isostatic Subsidence and a decrease in elevation Accumulation Of sediments and weighting Of the top of the crust causes further Subsidence

What is Orogensis

A mountain building process

Valley's are

A valley is gentley sloping Sidewalls that form where rocks sediments are more erodible In mountains , river eroded valleys are usually V shaped

What is an appropriate definition of an anticline

An arch shaped fold where the oldest rocks are in the center

Thrust faults

Angle less than 35 degrees , places older rocks on top of younger Common at leading edge f eoegenic deformation Shortens and thickens mountail belts

Riparian zone

Area at or next to viverbanks .

Accreted Terranes

Areas of crust on a subducting ocean plate that are too thick Cannot subduct and instead can get accreted to the margin Of a continent Examples : island arcs , seamounts , oceanic plateus

Strike slip

Block moves parallel to fault plane Strike

Dip Slip

Blocks move parallel to dip of fault

Channel paterns

Braided Anastomosing Meandering

Two major deformation

Brittle rock breaks by fracturing ... occurs in the shallow crust Ductile deformation by flowing + folding occurs @ higher Pressure + temp in deeper Crust

If you build a house in an area flooded last year by a " 100 - year " flood , what is the probability that a 100 - year " flood will occur this year ?

C.0.01

in straight channels highest Velocity is in the of the channel at or near water surface

Center

Compression is the dominant Stress in

Convergent boundaries + orogenesis

What kind of deformation occurs during continental rifting

Crustal stretching and thinning

Which two geological processes listed below can lead to isostatic uplift

Crustal thickening and erosion

A _________ stream network is the monst common occuring in flat lying strata , whereas a ______ stream network is associated with tilted strata in valley

Dendrtic , trellis

Development on deltas is at risk for

Development Subsidence

Deformation results in

Displacement , Rotation , Distortion

Strike Slip faults

Fault motion is parallel to the Strike of the fault Usually vertical w / no hanging wall- footwall

What is Detachment fault

Fault that is horizontal and forms as a result of a system of normal or reverse faults merging at depth

What is the distinction between faults and joints

Faults are fractures with displacement and joints are fractures without displacement

Suspended load

Fine particles ( Silt / clay ) in water

What kind of sedimentary basin forms at the edge of a mountain belt as a result of loading of the crust by the weight of the mountains

Foreland basin

Faults

Fractures with offset

Joints

Fractures without offset

Alluvium-

General term for sediment deposited by moving water

Which feature is most likely to be associated with a fold and thrust belt

Himalayas

Horizontal compression vs Shear

Horizontal compression - causes rocks to buckle Shear causes rocks 2 smear out

Increasing water depth=

Increased shear stress

How do the horizontal motions of the plate Icad to vertical motion of uplift or subsidence ?

Isostacy

How does the conversion of natural settings to urban settings affect movement of water precipitated onto the land ?

It increases surface runoff

Flood plain

Low relief area adjacent to river Chanel

Meandering Channel Pattern

Lower gradient Substrate Soft and easily eroded Broad valley evolue during times of flood - momentum increases during flood and erodes the outside bank

Foliation develops _____ to _____ motion

Parallel , shear Common in deep detachment faults

Dip is ________ to strike and measured ___________

Perndicular , downward

Plunging vs non plunging fold

Plunging has a hinge that is inclined (like a half a circle) Non plunging is horizontal hinge (Straight)

Hydrologic cycle Process

Precipitation - evaporation - infiltration Yon off - transpiration

What causes uplift

Replacing lithospheric mantle with hot asthenosphere , early stages of continental rifting , delamination of lithospheric mantle.

Fluvial Sediment-

Sediment in or deposited by a Stream system .

Basın

Shaped like upright bowl exposes younger rocks in center

What controls Stream competence ?

Shear stress increases W / increasing Water depth + increased slope Shear stress must overcome friction + conesion to move a particle

Shear

Sliding Past

-deposition occurs where

Slope / water depth decreases LOSS OF velocity Causes deposition .

If base level rises

Stream gradient + energy lessen leading to deposition

What controls capacity

Stream power

Strike vs Dip

Strike- Horizontal intersection w / a tilted Surface Dip angle of the surface down from Horizontal

Structural geology

Structural Study of rock deformation

Compactation and decay of organic matter causes

Subsidence

Type of deformation depends on

Temp + Pressure

Which is an appropriate definition for stream competence ?

The largest size sediment the stream flow can transport .

How would a stream profile be expected to respond to an increase in stream power ?

The stream profile would adjust down via erosion

How would a stream profile be expected to respond to a rise in sea level ?

The stream profile would adjust up via deposition

Which of the trends shown at right illustrates how the discharge varies along the course of a stream

Trend 2 blue

Reservoir residence time =

Volume / rate of exchange ( flux )

What is the definition of isostatic equilibrium in the context of the lithosphere and asthenosphere ?

When the lithosphere has dispced a mass of athenosphere = to the mass of the lithosphere

What is the name for the cycle of opening and closing ocean basins

Wilson cycle

drainage basin

a Area that drains into a Stream

Monocline

a fold like carpet draped over a Star Step

Syncline

a fold that opens upward like . a trough youngest rock is in the center of the Structure

Dome

a fold with an apperance of overturned bowl that exposes older rocks in its center

Hydrologic cycle

a summary of the Circulation of earths water supply through different reservoirs

Stream power is

ability for a stream to do work . It is commonly measured by multiplying shear Stress times the average velocity

Discharge

amount of water that flows through a channel

In a bedrock Stream

availibility of sediment may be limited

Competence Capacity both

change W / discharge .

Oblique Slip-

components of Both strike and dip

thalweg-

deep part of a channel where most flow occurs .

A Stream must lose paver to enter state Of

deposition

Tension is dominant in

divergent trifting Streches + thins material causing extension

Stream runoff Sculpts landscapes through

erosion deposition

Foliation

fabric Planar metamorphic

passive flow- fold

form in hot , soft , ductile rock at high temp

Deltas

form when a stream entersstanding water Stream divides into a fan of distributaries Water velocity Slows + Sediment drops out

Delivery of sediment to a stream is a

function of drainage basin slope + climate

Tension - Normal fault

hanging wall moves down relative to footwall

discharge _________downstream in a Stream drainage network in

increases

increasing slope =

increasing Shear stress

Which of the following processes of the water cycle transfers water into the groundwater reservoir ?

infiltration

Bed load

large particles roll , slide allong bottom ...

What are folds

layers sent by plastic flow

Flexural slip fold

layers slide past one another

total friction is ______ in deep narrow channels and_______in wide shallow Streams

least , greatest

Dissolved lood-

lons from chemical Weathering

Sediment load .

material moved by running Water

Competence

maximum clast size transported

Capacity

maximum load transported

Anastomosing Channel Pattern

multiple channels low gradient Vegetated banks More stable than braided Example Gulf Coast ( FL , Iouisiana )

in curved channels , fastest velocity is near the

outside bank

Mountain uplift is driven by

plate tectonics Convergent Plate boundaries Continental Collisions Rifting

Reverse + thrust faults

ranging wall moves op relative to footwall

Subsidence makes deltas more vulnerable to

sea level vise + storm flooding

Strain

shape change in shape caused by deformation Streaching (Pulling apart Shortening squeezing )

Two types of stress

tension- Hanging wall moves clown the fault Slope lengthening an area Compression hanging wall moves up the fault slope Shortening an area

Isostacy

the balance between the gravity forces polling down and bouyant forces Polling up .

Shear is dominant in

transform boundaries doesn't thicken or thins crust

Scarp

visibe when fault intersects surface . fault zones with breccia erode

Increases in discharge increase _________ + ________

water depth + competence