OUTLINE OF THE LECTURE – March 1, 2010

Urban Environmental Geography

GEOSPHERE – Earth’s processes… materials… features

 

Announcements -- Don't forget the field trip - 4 hours on April 10 or April 11 (Saturday / Sunday).

Rob / Jonathon... tectonics... LINK to info on 1960 Chile eq event ; and to info of 2/27/10 earthquake of Chile

 

Omot Dang, Parker Johnson; Jo Blake, and Charice Bourdeaux -- all okay... Parker... double check that I know the section and concepts you're covering.

 

Extension: the five (!!) lab assignments for geomorphic processes are extended to March 15. Why? to give you time to do the labs. Optional: if you like, turn in for feedback sooner. The analysis that applies concept to your city's setting. The midterm will cover: atmosphere, hydrosphere, geosphere... and cities' settings... not just your city.

 

REVIEW you should appreciate that the geosphere is a city's “foundation” …

 

Every subsystem of Earth systems influences a city’s setting.

The geosphere largely determines how a city can grow... and, to a large extent its scenery, physical resources (hydrologic as well as geologic); and natural hazards (think those interactions... how does the geosphere influence atmospheric hazards? hydrologic hazards? and geologic hazards?)...

 

To understand the geosphere, it helps to understand:

1. Effects of tectonics DONE THAT
2. Effects of time… deep time... GEOLOGY is CUMULATIVE.DONE THAT AND DO IT AGAIN
3. GEOMORPHIC PROCESSES... Effects of a four-part process... SEDIMENTATION (1. Weathering; 2. Erosion; 3. Transport; 4. Deposition) also known as (a.k.a.) "erosion / deposition"; a.k.a. geomorphology.

Tectonic processes work on Earth's crust from the inside. Driven by uneven heat in Earth's upper mantle.

Geomorphic processes work on Earth's crust from the outside. Driven by solar energy, the uneven distribution of heat (atmosphere, hydrosphere, ..., ..., ...)

Review... Big Science Concepts... (energy; some characteristics of matter; cycles; budgets; cumulative) link to listing

 

Approach... today I'll cover Chapters 10 - 12. Then Wednesday's presentations and lab.

Next week... more lab and presentations Monday 3/8, and I present and review Chapters 10 - 14 on Wednesday 3/10 with emphasis on Chapters 13 and 14.

 

Today: On one screen, I’ll show the PowerPoint slides of Christopherson that are posted on WebCT. On this screen I’ll supplement with lecture notes and tie to urban environmental geography.

 

REMINDER… Christopherson PowerPoint’s are on WebCT

Content is on web; in “physical geography” and “Earth systems” textbooks.

 

I can’t teach these five chapters (chapters on changes of Earth’s crust (geosphere) by processes of sedimentation) without thinking… always, heartbeat… about tectonics.

Tectonics sets the scene. Like a play. Then different actors play out their roles.

 

Christopherson – Slope mechanics and Form

 

GEOMORPHOLOGY – the shape of landforms

• Characteristic shape
• Characteristic materials (bedrock versus sediment)
• Characteristic processes

 

Think all three AND the goal is to understand process.

GEOG5810 – Analysis of Utah Landforms… Geog3330 counts as a prerequisite.

 

REMINDER... why does this matter to urban settings?

Scenery; resources; and hazards… mantra of geosphere thinking.

 

 

Christopherson – Chapter 10. WEATHERING, Karst Landscapes, and MASS MOVEMENT

 

SEDIMENTATION creates sediments (versus other processes of the rock cycle that produce other bedrock types).

 

FOUR sub processes to SEDIMENTATION

1. Weathering (in place … not move 6 in)
2. Erosion… transport… deposition… sediments have been moved

Agents of erosion / deposition… for urban environmental geographers:

Wind

Water

Glacial Ice

Ground failure

And now… Humans

C. Weathering

C. Regolith… soil… parent materials

C. Physical weathering

C. Joint – Block separation

C. Rockfall --- erosion, transport? Deposition

C. Sandstone – weathering

C. Exfoliation of granite

C. Chemical weathering

C. Spheroidal weathering

C. Oxidation in rock

 

WHY does this matter to Urban Environmental Geographers?

BECAUSE…

Geosphere is the foundation… sediments vs. bedrock

Scenery, Resources, Hazards

RESOURCES; Soil… so important economically to humans.

HAZARDS: buildings corroded (SLC City Hall); roads; problem soils.

 

Christopherson-- Karst.

Water dissolves the cement that holds grains of rocks together… and some rocks are “all” cement… cement is lime… from limestone

Concrete held together by cement. So is sandstone. So is conglomerate. So is limestone.

Dissolve it and there’s a hole

Scenery, Resources, Hazards … for Urban Environmental Geographers.

RESOURCES: water

HAZARDS: sink holes; pollutants move fast.

 

Christopherson – Mass Movement Processes

Processes of --

EROSION – transport – deposition.

Also called “GROUND FAILURE”

Gravity alone… all agents of erosion / deposition obey the laws of gravity

Remind… five agents of geomorphic change?

Usually more than one agent at work… WATER …always remember water. Hydrosphere – Geosphere interactions. What is geography? What is physical geography? What are the 5 subsystems of Earth systems? Empower by understanding… Urban environmental geography.

 

C. Mass Movement

Big and small

C. Madison River Landslide. Ron’s tectonics talk of hazards. 17? Utahns killed here.

 

C. Classes of mass-movement GREAT SLIDE… (ho ho) … slower faster; wetter drier, steeper gentler.

 

C. Talus

C. Debris avalanche

C. Creep

C. Scarification

Why matter to Urban Environmental Geographers?

Scenery, Resources, Hazards

Scenery

RESOURCES – transportation corridors

HAZARDS – lots and lots… small and big… maintenance and catastrophe.

 

END OF CHAPTER 10

CHAPTER 11 – RIVER SYSTEMS and LANDFORMS

Some concepts… tie to tectonics… sets the stage. Tie to hydrosphere and water cycle

Earth systems… empower by understanding.

Preview of concepts… Base level; Drainage Basin; Drainage density and patterns.

 

Series of Christopherson slides…

WHY does BASE LEVEL matter to Urban Environmental Geographers?

SCENERY

RESOURCES

HAZARDS. 

 

Christopherson - Stream flow characteristics

CONCEPT: Gradient… atmosphere… hydrosphere… geosphere…

Earth SYSTEMS.

C Channel Response

C. Discharge

C. Fluvial transport

C. Braided stream

C. Meandering stream.

C. Alaska

C. Boundaries

C. Profiles … GEOG3330.

C. Entrenched meanders.

C. Nickpoint (knick point)

C. Niagara falls

 

Christopherson – STREAM DEPOSITION

Big deal!!

Erosion – Transport – Deposition

Erosion – Deposition are a couplet.

Deposit SEDIMENTS (MATERIALS)

Shapes of natural features on surface are LANDFORMS… depositional landforms as sediments deposited. By PROCESSES.

 

Why do stream characteristics and stream deposition matter to Urban Environmental Geographers?

Scenery – location location location. Where cities locate. Sense of Place. Interact. Migration.

Resources – don’t underestimate the importance of dirt. Soil. Sand Gravel.

Hazards – associated with floods (overbank, and undercut)

 

Christopherson – FLOODS and RIVER MANAGEMENT

Big Deal!!

 

END of CHAPTER 11

CHAPTER 12 – WIND PROCESSES and DESERT LANDSCAPES

Earth systems: atmosphere, hydrosphere, geosphere, biosphere, anthrosphere.

Review concepts:

Geomorphology: always think MATERIALS, LANDFORMS, PROCESSes

Materials:

Landforms

Processes

Why is this important to Urban Environmental Geographers?

Scenery, Resources, Hazards

It’s a system: atmosphere… weather and climate…

 

Christopherson – march through … “straight forward”

Loess – important for economics – Oregon and Idaho.

Cities… sand … encroachment

Alluvial fans – Flash floods… important to Las Vegas.

DESERTIFICATION…

Why are cities NOT in deserts? That’s how this chapter applies to Urban Environmental Geography.

END OF CHAPTER 12.

 

 

 

 

 

{Students of Geog/Envst3330 -- for powerpoints of lectures, go to your UofU WebCT / Blackboard course files }

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