Geography 104 Final UWEC

Physical Geography

Study of spatial and temporal processes which shape the physical characteristics of the Earth

Earth's Four Spheres

1) Atmosphere

2) Lithosphere

3) Hydrosphere

4) Biosphere

Parts of a System

1) Inputs

2) Actions

3) Outputs

Relief

Elevation of local landscapes - highest, lowest, average

Topography

Character and configuration of the Earth's surface

Geomorphology

Study of the Earth's surface features and the processes that shape them

Geologic Time Scale

Relative time/absolute time

Principle of Superposition

Relative position of rock strata

Principle of Uniformitarianism

"The present is the key to the past"

Concept of Catastrophism

"Opposite" of Uniformitariansim

Continental Drift

Theory that the crust of the Earth is composed of a series of plates that float about on the denser underlying material

Evidence in Support of Continental Drift (6 things)

1) Coastline Fit

2) Geological Fit

3) Paleoclimatology

4) Paleoglaciation

5) Fossil Correlation

6) Paleomagnetism

Theory of Plate Tectonics

General theory of lithospheric plates with their relative motions and boundary interactions

Plate Boundaries (3 types)

1) Divergent (spreading)

2) Convergent

3) Transform (transcurrent)

Fold in the Earth's Crust (3 parts)

1) Monocline (one fold)

2) Anticline (incline)

3) Syncline (decline)

Fault

A plane or rock fracture along which there is motion of the rock mass on one side with respect to that of the other

Types of faults (5)

1) Normal fault (tension)

2) Reverse or thrust fault (compression)

3) Strike-slip or transcurrent fault (lateral shearing)

4) Graben (tension)

5) Horst (compression)

Richter Scale

Logarithmic - amount of energy released approx. 31 from M 1.0-2.0

Seismograph

Records vertical and horizontal motion of Earth and magnitude of motion

Tsunami

Large waves that record seismic activity

Liquefaction

When strength and stiffness of soil is reduced due to earthquakes

Cycle of Gradation

1) Erosion (degradation)

2) Transportation (gravity, wind, water, ice)

3) Deposit (aggradation)

Glaciers

Slowly moving mass of dense, year-round ice

Snow Line

Lowest elevation where snow remains year round (in high latitudes, high elevations)

Conversion of snow to ice (3 stages)

1) Loose snow

2) Firn (between snow/ice)

3) Glacial ice

Glacial Mass Balance

1)Zone of accumulation/zone of ablation

2) Equilibrium line

Glacial erosion

1) Abrasion

2) Plucking

Glacial erosion features

1) U-shape valley

2) Glacial trough

3) Striae

4) Glacial polish

5) Glacial flour/rock flour

6) Cirque

7) Arete

8) Horn

9) Col

10) Hanging valley

11) Tarn

12) Paternoster lakes

13) Fjord

14) Rouche Moutonnee

15) Drumlins

U-shape valley

A valley formed by glaciers that looks like a U

Glacial Trough

Basically a U-shape valley

Striae

A linear mark, slight ridge, or groove on a surface, often one of a number of similar parallel features

Glacial Polish

A characteristic of rock surfaces where glaciers have passed over bedrock

Glacial flour/ Rock Flour

Fine-grained, silt-sized particles of rock, generated by mechanical grinding of bedrock by glacial erosion

Cirque

A theatre-like valley formed by glacial erosion

Arete

A sharp mountain ridge

Horn

An arete

Col

The lowest point of a ridge or saddle between two peaks

Hanging valley

A valley that is cut across by a deeper valley or a cliff

Tarn

A small mountain lake

Paternoster lakes

One of a series of glacial lakes connected by a single stream or a braided stream system

Fjord

A long, narrow, deep inlet of the sea between high cliffs

Rouche moutonnee

A small bare outcrop of rock shaped by glacial erosion, with one side smooth and gently sloping and the other steep, rough, and irregular.

Drumlins

A low oval mound or small hill, typically one of a group, consisting of compacted boulder clay molded by past glacial action

Glacial debris/deposits

1) Supra (above)

2) En (in)

3) Sub (under)

Till/Moraine

Contact with ice when deposited (usually unsorted)

Drift

Deposited directly or indirectly by a glacier

Moraines (5 types)

1) Lateral

2) Medial

3) Terminal

4) Recessional

5) Ground

Glaciofluvial Deposits

- Meltwater with ice when deposited

- Usually sorted wide range of deposits

- Wide range of deposits

- Wide range of sediment sizes

- Outwash plain, drumlins, eskers, kettle holes

Classification of Glaciers (2)

1) Alpine

2) Continental

Alpine Glacier

Ice cap, ice field

Continental Glacier

Ice sheet

Glacier Movement

Crevasses, glacial surge

Antarctica

Each year the continent approx. doubles in size due to the growth of the sea ice

Quaternary Glaciation

Cycles of glaciation and deglaciation

Glacial Stages (2)

1) Wisconsinan (glacial)

2) Sangamonian (interglacial)

3) Pre-Illinoian

Glaciation

- Changed much of the landscape

- Lowered sea levels and temperatures

- Much information from ice cores

- Paleoclimatology

Fluvial (Latin word: fluvius)

Meaning river or stream

Alluvium

Sediment deposited by a stream (gravel, sand, silt, or clay)

Gradient/slope

vertical distance that channel falls between two points

Longitudinal profile

Change in gradient from the stream source to its outlets

(K)nickpoint

When longitudinal profile has an abrupt change in gradient (waterfall)

Base level

Level below which a stream cannot erode its valley

Stream erosion

Hydraulic action, bank caving, abrasion/attrition, solution (corrosion)

Stream transportation

Solution, suspended load, bedload

Stream deposition

Decease in flow, deposition )deltas, alluvial fans)

Meandering channels

Single channel, suspended sediment, point bar, cut bank

Braided channel

Coarser sediment, bedload dominated, fluctuating discharge, steeper gradient

Channel/Alluvial Terraces

- Level areas that appear as topographic steps above a stream

- Created by the stream as it scours with renewed downcutting into its flood plain

Entrenched Meanders

Incised river meanders excavated deeply into the landscape, rejuvenation

Floodplain Landfoms

A flat, low-lying area along a river, crated and subject to recurrent flooding, levee formation

Runoff

precipitation - evaporation+/- change in storage

Drainage Basin

Basic spatial geomorphic unit of a river system

Streamflow

Q = (A)(v)

Stream Gages

Measures height of water flowing

Flood Hydrograph

Graph of stream discharge over a time period for a specific place, lag time, peak, rising limb, falling limb, base flow

Flood Abatement Measures

- Detain and delay runoff

- Modify the lower reaches