Download WebText- GEOGRAPHY OF UTAH

WebText- GEOGRAPHY OF UTAH
Chapter 6 –Utah Geography and Utah’s Geosphere
DRAFT webtext by G. Atwood, 2012
Use with professional courtesy and attribution including attribution of original sources where indicated.
LINK to printable version… it may differ a bit from this web-posted version.
CHECK THIS
Subtitle:
Utah, the Bedrock State… or is it?
BIG CONCEPTS: (reminder: Geography of Utah can be explored via themes of geography – Part 1 of this
web-text, via each of the subsystems of Earth systems – Part II of this web-text, and via issues of social
and behavioral science. The five subsystems of Earth systems are: geosphere, hydrosphere, atmosphere,
biosphere, and anthrosphere. This chapter explores Utah’s geosphere, its interactions with Utah’s physical
geography and its imprint on Utah’s human geography.)
Place connects us to location, and the geosphere.
The geosphere connects us to place and location... and all 15 Words of GeogUT
The GEOSPHERE is the first of the sub-systems of Earth systems.
Physiographic provinces are regions based on the geosphere.
Landforms, Landmarks, and Landscapes.
Physiographic provinces look different.
Physiographic provinces look different because they are different.
Tectonics has set the stage for Utah's landforms and geologic materials. Tectonics 101 and Utah’s
geosphere.
Sediments tell the geologic story of the present. Bedrock tells the geologic story of the past. Earth
materials 101 (the Rock Cycle) and Utah’s geosphere.
What-is-now-Utah has a long geologic history. (It's okay to skip this section… included by students’
request)
Three regions based on landforms... about Utah’s 3 physiographic provinces
The geosphere is the basis for scenery. Utah's three contrasting regions (physiographic provinces)
mean 3 regions of contrasting scenery.
The geosphere is the basis for geologic hazards. Utah's contrasting physiographic provinces mean
diverse natural hazards.
The geosphere is the basis for geologic resources. Utah has diverse sets of geologic resources,
because of diverse rocks, because of rgionally-diverse geologic histories.
EVIDENCE. Examine these images as Geographers of Utah.
Hintze-GeologicMapUT-8x11
SternerDEM-AtwoodPhysProvGeneralizedUT
RiddBase-AtwoodPhysProvDetailUT
WSU-Greer-UT_Elevation_Atlas_p018
Hamblin2004-p228-TuleValley
Hamblin2004_p114_MonumentValley
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Hamblin2004_p211_NaturalistBasin
Quotation:
Need a nifty quotation… Stokes?
LINK to The 15 Words of GEOG3600 and version that can be printed.
CASES:
Utah in the News.
WSU-BYU-Greer-BinghamCopperMine-p025
Topics… Questions to Ponder –
Just as PLACE connects us to LOCATION… how does the geosphere connect us to place?
How much of your sense of place of wherever… but especially of Utah… relates to some aspect of the
geosphere (scenery, landmarks, topography, job… )?
Why does Utah have such spectacular big bold red geology in southeastern Utah and subtle drab geology
in western Utah?
Overarching Goal of the Chapter:
Look at the geoscience that surrounds you and recognize how it affects you… your life style, your taxes,
your sense of place. If you’re new to recognizing the Earth science that surrounds you, first, recognize that
you are surrounded by (a) landforms… characteristic shapes on Earth’s surface; (b) Earth materials and
recognize bedrock versus sediment, (c) Earth processes. Ask yourself: How have Utah’s big bold
landscapes come to be? How did their materials come to be? Embrace uncertainty. Embrace curiosity.
Embrace wonder.
MAJOR CONCEPT:
Utah’s geosphere is the foundation of Utah’s physical geography and integral to Utahns’ sense of place. It
is the stuff that landmarks are made of… and, recall that landmarks are one path to a sense of place.
Utah’s geosphere has causal connections to some of the highest paying jobs, highest value exports and
greatest potential natural disasters.
Addendum / clarification / expansion on the “major concept”…
Utah has three contrasting physiographic regions because of cumulative effects of geologic history. This
means Utah has three sets of scenery, three sets of geologic resources, and three sets of geologic
hazards.
Specifics: by the end of this chapter… you should:
Know Utah’s three physiographic provinces (REGIONS of Utah based on landforms).
Understand the basis for the boundaries (and boundary dilemmas) of the physiographic provinces.
Memorize that: the geosphere largely determines Utah’s natural resources, natural hazards, and scenery.
If you want to appreciate the geosphere, think: Materials, Landforms, and Processes.
All of Utah’s scenery results from (1) tectonics; (2) erosion / deposition.
All of Utah’s geologic resources result from the rock cycle… that is driven by (1) forces with Earth =
tectonics; and (2) forces on the outside of Earth = erosion / deposition.
Tectonics is the study of movements of Earth’s crust (the very outer skin --literal crust-- of Earth). Crustal
movements within the North American plate cause many of Utah’s landforms and hazards.
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Be able to connect concepts of the geosphere with The 15 Words of GEOG3600.
Coaching for students of UofU GEOG3600-Geography of Utah:
You’ve memorized the Five Themes of Geography. (Location, Place, Interaction, Migration/Movement, and
Region), now, memorize the five subsystems of Earth systems:
The GEOSPHERE is the solid Earth
The HYDROSPHERE is the water Earth,
The ATMOSPHERE is the gaseous Earth think… weather and climate,
The BIOSPHERE is the living Earth, and
The ANTHROSPHERE is the human footprint on Earth.
Reminder: REGIONS (chapter 4 of this web-text) are relatively large areas with important similarities…
continuous, contiguous, and cohesive. Utah’s physiographic provinces are regions based on the
geosphere, specifically, on landforms.
Terms to understand with respect to GEOSPHERE
Understand these terms (a) because they indicate mastery of content, and (b) for the mid-term (use your
own words) or on quizzes
GEOSPHERE
Landmarks
Landscape
Landforms
Topography (from the Greek for position or place… )
Relief
Materials
Rock cycle
Bedrock
Sediment
Tectonics
Processes of erosion and deposition
Geologic resources
Scenery
Geologic hazards
Earthquake
Scarp
Fault scarp
Fault
Wasatch Fault
Basin and Range physiographic province
Colorado Plateau physiographic province
Rocky Mountain physiographic province
Earth systems
Physical geography
THEORY / CONCEPTS towards an understanding of GEOSPHERE and geography of UTAH
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1. The GEOSPHERE is the first of the sub-systems of Earth systems.
Need a Venn diagram for 5 subsystems of Earth Systems... KumpEtAl-TheEarthSystem book cover
Hamblin2004_p181_Ogden_lookingEast used with permission
Earth is a system… with subsystems that interact. Earth systems science (according to Don Kennedy,
Stanford U) is simply a fresh word for physical geography. Why have two terms? Earth systems is the
modern term. Physical geography sounds boring to some folks. So the terminology is partly marketing.
From a geologist’s perspective: the FOUR subsystems of EARTH SYSTEMS are… geosphere,
hydrosphere, atmosphere and biosphere. Geographers have the fifth subsystem, the anthrosphere, also
called the technosphere.
Earth systems.
All systems (a) have subsystems, and (b) those subsystems interact… usually non-linearly, meaning with
feedback loops. As Fred Montague (UofU ecologist) says: “It’s a loopy world.” A house is a system. Utah’s
geosphere can be thought of as the foundation of Utah’s physical geography, much the foundation of a
house.
2. Physiographic provinces are regions based on the geosphere.
Hunt1974_PhysProvUS
Hunt1974_PhysProvWest
USGS-USA-DEM
Ridd_BaseLandforms_AtwoodPhysProv
Regions (review from Ch05) are large areas with important similarities: continuous, contiguous, and
cohesive.
Physiographic provinces are regions based on the GEOSPHERE, defined by landforms. Note the subtleties
of that definition. It implies, rightly, that regions based on the geosphere might have been defined on
aspects of the geosphere other than landforms, for example, on tectonics or on bedrock. However…
landforms are the basis for defining physiographic provinces.
Landforms are a good proxy for the GEOSPHERE because landforms are the product of tectonics and
erosion / deposition. Tectonics sets the scene (determines elevation and differences in elevation). Erosion /
deposition sculpt the scene into scenery… into landforms.
Topography … from the Greek word for position or place… is the lay of the land based on elevation.
Elevation is distance above a datum, generally sea level. Great Salt Lake’s average historic elevation is
4200 ft a.s.l. (feet above sea level). Utah’s highest peak is Kings Peak at 13,528 ft a.s.l.. Utah’s lowest
place is where Beaver Dam Creek (a tributary of the Virgin River that, in turn, is a tributary of the Colorado
River) crosses the Nevada – Utah state line at 2000 ft a.s.l.
3. Landforms, Landmarks, and Landscapes.
Atwood-DelicateArch
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Landmarks are cultural or physical features that act as a guidepost or recognizable features for
connectedness with place. Landscapes are entire scenes.
Landforms are components of landscapes.
Landforms are characteristic features on Earth’s surface with characteristic materials, characteristic shape,
and created by characteristic geologic processes.
Here are more formal explorations from Glossary of Geology (Jackson, 1997):
Landscape = a composite of physical and biological features that form a scene. (p. 357): “The distinct
association of landforms, esp. as modified by geologic forces, that can be seen in a single view, e.g. glacial
landscape.”
Landform: (p. 357) “Any physical, recognizable form or feature of the Earth's surface, having a
characteristic shape, and produced by natural causes; it includes major forms such as plain, plateau, and
mountain, and minor forms such as hill, valley, slope, esker, and dune. Taken together the landforms make
up the surface configuration of the Earth. Also spelled: land form.”
My (G. Atwood) definition of a landform: a geologic feature on Earth’s surface with (a) characteristic shape;
(b) characteristic materials; and (c) formed by characteristic processes.
Note: some landforms are in all three of Utah’s physiographic provinces. Some are characteristic of only
one province. But the composite of the landforms, the landscapes differ. As a geomorphologist (someone
who studies landforms and the processes that make them) it is difficult for me to imagine that anyone
wouldn’t enjoy comparing and contrasting the landscapes of Utah’s 3 physiographic provinces.
4. Physiographic provinces look different.
Hunt1974_PhysProvUS
Hunt1974_PhysProvUT
SternerFermi_UT_DEM_gray
RiddBase_LandformsUT_Atwood_PhysProv
Think about places you’ve lived or visited outside of Utah. It should be intuitively obvious that Iowa’s
landscapes are not those of Montana, or of coastal Virginia, or of mountainous Colorado. C.B. Hunt, who
adopted Utah as his home state, classified the US+Canada into about 15 physiograpic regions. His regions
resemble those of other geologists who have preceeded and followed him. I use Charlie’s maps (a)
because of fondness; (b) they are clear; and (c) he gave me permission to use his materials.
Look at the gray elevation model (DEM) by Ray Sterner. Where would you draw the boundaries... if you
could have at most five provinces?
Merrill Ridd of the UofU Geography Department developed a 1:2,000,000 scale schematic of Utah’s
landforms across which I have drawn what I teach as Utah’s physiographic provinces. Note: the underlying
map is Dr Ridd’s and the lines may not be those he would choose. One state, two geographers, three
opinions (maps)!
RIDD-Atwood for Utah
5. Physiographic provinces look different because they are different.
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Stokes-ContrastAcrossWasatchLine
Hintze-GeologicMapUT_8x11
ADD stratigraphic column
Geology is cumulative. Places have different geologic past. Utah has three physiographic provinces
because these areas of the North American craton have had different geologic pasts… and present. To
understand geologic settings it helps to know a few geologic concepts… even though this is a course in
GEOGRAPHY of Utah, not geology of Utah.
Earth is dynamic.
They say… one house, different homes. Don’t expect all of Earth to be the same. Imagine South America’s
terrain today with the Andes to the west and Amazon to the east. Those regions are experiencing different
geologic processes today. So it should be no surprise that a region as large as the western North America
has had regions that are experiencing contrasting geologic processes today… and that have experience
the cumulative effects of different geologic processes over geologic time. Utah has three physiographic
provinces with their contrasting scenery differ because of contrasting geologic histories.
Tectonics has set the stage for Utah's landforms and geologic materials. Tectonics 101 and Utah’s
geosphere.
Atwood_Earth101-01_EarthIsDynamic
Leeds_Isostasy
SkinnerPorter_CrossSectionUS_Isostasy
USGS_DynamicPlanet2009_Front
USGS_DynamicPlanet2009_Back
USGS_web_PlateBoundaries
UNAVCO-GPSmovementsWestUS
Silver_UnderlyingMantle
ESE_ExtensionOfBasinAndRange
UGS_UUSS_EqEvidence
UGS_CEM_FaultEvidence
UGS_ImageLittleCottonwoodCny
Bowen_TooeleCo_WendoverLookingEast
Tectonics is the study of movements of regions of Earth's crust, and "tectonics" is shorthand for those
momements and their effects. Processes of tectonics largely explain gross elevation differences across
Utah. Tectonics of the past, meaning about dinosaur time, raised all of Utah about a mile or so above sea
level. Continued tectonism and igneous activity has made some regions even higher. What is now the
Colorado Plateau and what is now Utah’s portion of the Rocky Mountain physiographic province has stayed
high. But extensional tectonics has created the Great Basin (region of internal drainage) and the structure
of the basins and ranges of the Basin and Range physiographic province.
In the broadest of terms, today’s Basin and Range physiographic province looks different because, for the
past 15-20 million years, it has been in a different tectonic environment than eastern Utah. Plate tectonics
is a phrase that refers to processes by which Earth's crust, broken into large plates, floating on Earth's
surface, move with respect to each other. All of Utah is on the North American plate. What is important for
Utah geography are tectonic changes within the North American plate. The Basin and Range is literally
being stretched by extensional tectonics. GPS data, satellite data, geophysical data show that all of North
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American plate moves west with respect to Hawaii, but much of the west coast (for example, San
Francisco, CA and Portland, OR is moving west faster than Denver, CO; Chicago, IL; or Miami, FL. So…
something has to give! The stretching causes the broken terrain, the faults, the basins, and the ranges of
the Great Basin (the region of internal drainage of western US).
The Wasatch fault is the eastern margin of the faulting of the Basin and Range. The Wasatch fault and its
continuation along the Hurricane fault of southwestern Utah, define the eastern margin of Utah’s portion of
the Basin and Range physiographic province. Between those two major faults there may be some
uncertainty of “the” boundary. Note how this uncertainty opens opportunity for discussion of processes. It is
not an issue of right or wrong but of logical distinctions based on a set of criteria.
Compared to the Basin and Range, the Rocky Mountain and Colorado Plateau physiographic provinces are
dramatically more stable. Why? The Rocky Mountain physiographic province is "rooted." The Colorado
Plateus is loosing mass and rising like an iceberg losing its mass.
The effects of tectonics on processes of erosion and deposition can be dramatic. The basins of the Basin
and Range capture sediments eroded from the ranges. The result is broad, sediment-filling basins and
north-south, elongate, fault-bounded ranges. The tectonically stable and isostatically balanced (floats like
an iceberg that is not losing mass) Rocky Mountain physiographic province rides high and is eroded by
streams and rivers into myriad drainages and montane valleys. The tectonically relatively-stable but
isostatically im-balanced (floats like an iceberg that is losing some of the mass off its upper parts) Colorado
Plateau has rivers that have sliced through thousands of feet of bedrock as they carry sediments toward
the Pacific Ocean.
6. Sediments tell the geologic story of the present. Bedrock tells the geologic story of the past.
Earth materials 101 (the Rock Cycle) and Utah’s geosphere.
Hamblin2004-p228-TuleValley
Hamblin2004_p114_MonumentValley
Hamblin2004_p211_NaturalistBasin
Tectonics explains much of Utah’s landscapes, it sets the scene, but tectonics alone does not explain the
big bold red terrain of the Colorado Plateau, the handsome maroons and grays of the Rocky Mountain
physiographic province, and the subtle, sometimes referred to as drab, tans and grays of the Basin and
Range. This web-text, Geography of Utah is not a textbook in geology of Utah. Geographers of Utah do not
need to understand the rock cycle. But any person from artist, writer, hiker, prospector, cardiologist will be a
more educated person if they appreciate the major paths of the rock cycle.
ESE – Rock cycle handout.pdf
ESE-Bedrock vs Sediment;
ESE-Four Processes four products.
ESE – Animated rock cycle
At minimum, a geographer of Utah should recognize bedrock versus sediment:
•
Bedrock means…. Firm, coherent, attached as a continuous solid mass to Earth’s crust.
•
Sediments mean… Not firm, not coherent, and not attached continuously as a solid mass to
Earth’s crust.
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•
Soils are sediments. Not all sediments are soils.
•
Underneath all sediments there is bedrock. There is not sediments under bedrock except under the
most extraordinary conditions.
•
Under close inspection these meant-to-be-helpful defintions fall apart because there in no moment
when sediments become bedrock, and some igneous bedrock is firm, coherent, but not continuously
attached to Earth’s crust, but… if you want to enjoy Utah landscapes, be able to distinguish the loose rock
from the bedrock.
Coaching: Many of us learn there are three types of rock: sedimentary, metamorphic, and igneous. But that
is geology jargon and shorthand. To appreciate Utah’s geography, its geosphere, it’s essential to recognize
that those three rock types refer to bedrock, the firm, coherent, continuous, rock crust of Earth. Instead of
those three bedrock types, first train yourself to observe sediments versus bedrock. Sediments are loose.
All sediments come from bedrock, directly or indirectly. If you can pick a rock up, it’s sediment. If you have
to blast it to separate it from firm, coherent, continuous rocky crust… it’s bedrock.
More coaching… don’t confuse sediments and sedimentary bedrock. Why not? Sediments tell the story of
the environments of the present. Sedimentary bedrock records the environments of the past. The cliffs of
the Colorado Plateau are made of sedimentary bedrock. The loose rocks in the river channels are
sediments.
Utah
7. What-is-now-Utah has a long geologic history. (It's okay to skip this section… included by
students’ request)
Lehi F. Hintze, former BYU geologist, and renowned geologic mapper and academic, has divided Utah’s
4.5 billion year history into 9 phases based on the changed tectonic settings through time.
These images are posted with permission of their author, William Lee Stokes. Do not copy or use without
attribution.
Coaching about analogues: when I use an analogy of today’s locale (e.g., Chapter 1 of Utah's past is like
what is along the Alaskan coast today) I'm talking geologic processes so... don’t imagine today’s life forms
or today's atmosphere back then.
CHAPTER 1: Metamorphic basement, like along Alaska ’s southern coast
CHAPTER 2: Metamorphism lite,
CHAPTER 3: Shallow seas. Seas advance and retreat, for millions of years... the topography looked like
the topography of the Bahamas today
CHAPTER 4: Broad basins. Shallow seas with regions of enormous thick basin fill, for millions of years,
analogous to the Gulf of Mexico's topography and the gulf's sediments of today
CHAPTER 5: Land and Lizards: Dinosaurs and deserts, lived on land, ate vegetation in swamps, and
Utah's topography went from mostly seas to mostly land with changed and changing topograhy analogous
to the Mediteranean and its environs today
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CHAPTER 6: Scrunch and swamps. The Wasatch line, a region where Earth accomodated change,
scrunched due to compressional tectonics and became high mountains... like the Andes. And western Utah
(back then) resembled the Amazon today - vegetation, low relief... and... dinosaurs lots of dinosaurs.
CHAPTER 7: Uplift, high plateaus and the Uintas. The tectonic environment "relaxed" from compressional
mode. The result was that "Utah" rose a mile... going from pretty close to sea level, to become high terrrain,
perhaps analogous to high plateau of China.
CHAPTER 8: Voluminous volcanics, impressive intrusions, and emplacement of metallic riches
CHAPTER 9: Today… now stretch! Tectonic setting... you know this... this is our Utah... extensional
tectonics... break up of the Basin and Range, and ... climate change (alternating global glacial times and
global interglacial times). We live in a global interglacial stage.
Dr. Hintze and I (GAtwood) teach by chapters rather than by traditional geologic periods to emphasize
changes in tectonic regimes.. and de-emphasize jargon. Hintze-GeoMapUT; Hintze- -InsideCover
Andy Godfrey (USForestService and UGS) show the progression using traditional geologic time frames
Gofrey-UGS-PubInfo54
8. Three regions based on landforms... about Utah’s 3 physiographic provinces
Ridd-Atwood-MapOfUtahLandformsPhysProv
Hamblin2004-p228-TuleValley
Hamblin2004_p114_MonumentValley
Hamblin2004_p211_NaturalistBasin
I. Basin and Range physiographic province ESE-SchematicBasinAndRange
Tectonic setting – extensional and active… thin crust being ever stretched out and broken
BLOCKS
Landforms:
Big expressions: basins and ranges ... wonderful images by BOWEN (Wendover looking east) or could do
GOOGLE EARTH live ... and, of course Hamblin2004-p227-HouseRange
Local expressions:
•
closed basins (and closed basin lakes, sediment depo-centers, shorelines, etc) WSU-BYUGreer=AtlasUT-Satellite-p000
•
fault related (scarp, chopped off mountain fronts with chopped off whatever-was-in-the-way, triangular
facets, greatest snow on Earth, etc)
•
ranges (run north south because extension pulls east west, low at both ends and high in the middle,
usually one side steeper than the other because range front faults are usually not equally active)
•
Low is depositional = basins with basin fill
•
Basin and Range characteristics Atwood-PhysProvChar-BasinRange
II. Rocky Mountain physiographic province
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Tectonic setting – very stable, thick crust, isostatic equilibrium… (does not play well with others)
Landforms: (plastic relief map) BOWEN Uintas looking west; Hamblin2004-p208-MtPowell; Google Earth
(active)
Big expressions: major massive mountainous terrain with broad “parks”
Local expressions:
•
Mountains of many shapes and sizes (depending on erosion/deposition histories)
•
Drainages of many shapes and sizes
•
Lots of glacial activity (more farther north)
•
Both erosion and deposition. Both bedrock and sediments.
•
Low and erosional = valleys, “open” not closed, marshes, fresh water lakes
RockyMountain Physiographic Province generalized characteristics - Atwood
III. Colorado Plateau physiographic province
Tectonic setting – very stable…. And rising like an iceberg, isostatically (not fast and pretty evenly) because
so much material is being eroded, the “iceberg” rises … may be confusing… land surface gradually
lowering, but rock units rising. Careful… the upwarps and downwarps pre-date “today’s” conditions.
HAMBLIN - Grand Staircase; HAMBLIN - Gr Staircase Sketch; HAMBLIN Monument Valley; BOWEN
Grand Co; BOWEN San Juan; Google Earth (live)
Landforms:
Big expressions: big bold brassy red extensive, nearly-flat lying, relatively undisturbed, layered sedimentary
bedrock exposed as plateaus, mesas, etc.
Local expressions:
•
Mesas, etc
•
Low and erosional = canyons
Colrado Plateau physiographic province generlized characteristics - Atwood
9. The geosphere is the basis for scenery. Utah's three contrasting regions (physiographic
provinces) mean 3 regions of contrasting scenery
Hamblin2004-p228-TuleValley
Hamblin2004_p114_MonumentValley
Hamblin2004_p211_NaturalistBasin
Is the landscape dominated by bedrock or by sediment? Your first impressions.
What is the high terrain like? (mountains, plateaus, ridges...). Understand observations versus
interpretation... I see... versus I think.
What is the low terrain like? canyon bottoms, valleys, broad basins...)... I see... versus... I bet it's like...
How steep are the landforms (individual elements of the landscape)? Could you climb them safely?
Describe the profile (outline, shape, and angles) of major landforms… Steep? Smooth? Jagged? Rounded?
Flat? Long? Symmetrical? Horizontal?
What erosional agents are acting on the bedrock... and might have been acting on the scene during the
more recent Ice Ages? Meaning, what agents of change on Earth's surface are picking up pieces of rock
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(meaning sediments), transporting them, and depositing them somewhere else that could be near (a few
inches away) or far (a mile or more).
Is erosion dominated by water running across the surface, or wind, or glacial ice carving out passages, or
ground failure where incompetent materials fail... or human beings?
What depositional processes have left the sediments? Remind yourself... what are sediments versus
bedrock? What is deposition versus erosion?
Describe a few landforms... characteristic natural features on Earth's surface.
How resistant are these landforms to erosion? What is your evidence?
Discuss patterns of the landscape such as colors of materials, patterns of vegetation, patterns of drainages
What are the dominant colors the scene's bedrock? of the scene's sediments?
For our purposes we'll say that dominated by bedrock means bedrock within 1 m (3 ft) of the land surface...
How much vegetation is supported on the bedrock? And on the sediments?
What is the proportion of bedrock versus sediment in the scene? Therefore is the scene dominated by
erosion or by deposition?
Ties SCENERY / PLACE / GEOSPHERE to issues of social and behavioral science:
Land Ownership:
Land ownership: Of United States; Of Utah BLM ForestService; Add Military; By county BLM; Utah Private;
Utah owned State; Utah state parks; Utah Federal and State;
Anthropology:
Demographics:
Economics:
Political Science:
Sociology: Quality of life
10. The geosphere is the basis for geologic hazards. Utah's contrasting physiographic
provinces mean diverse natural hazards
Hazard maps... tie to themes of geographphy... Location, Place, Interaction, Movement, Region
National Map: Hurricanes; Floods; Tsunamis; Volcanoes; Groundshaking; Wildfire; Landslides.
Utah Hazards information from Utah Geological Survey:
Seismic hazards http://www.ussc.utah.gov/publications/roots_earthquake.pdf
Ground failure (rockfall, landslides, debris flows):
http://geology.utah.gov/utahgeo/hazards/landslide/index.htm
Flooding: Great Salt Lake: http://geology.utah.gov/utahgeo/gsl/index.htm
Radon: http://geology.utah.gov/utahgeo/hazards/radon.htm
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Earth systems is a system! The geosphere is a subsystem of Earth systems. (a) Natural resources, (b)
scenery, and (c) geologic hazards are a package deal. You can’t have the greatest snow on Earth without
our Wasatch fault (and its predecessors). Great Salt Lake is a closed basin lake due to tectonics and
snowmelt.
Utah’s natural hazards are not randomly distributed.
•
The boundary between the Basin and Range to the west and the higher country to the east, where
most of Utah’s population has chosen to live is where Utah’s greatest assortment of natural hazards, and
Utah’s greatest risk from geologic hazards are found. The greatest single hazard with risk to over a million
people, potential loss of life of hundreds and potentially a few thousand, and property damage in the billions
to recover from is a major, greater than 7 magnitude earthquake on one of the segments of the Wasatch
fault that exposes the most population.
•
Resulting hazards of steep terrain along the Wasatch line include landslides and flooding
•
The next greatest risks are drought and fire, indirectly associated with the geosphere but
associated due to terrain.
•
Flooding. landslides, and radon hazards are in part due to Earth terrain and materials.
• Specifically, the Basin and Range province is tectonically active, prone to earthquakes and their
associated hazards (ground shaking, surface rupture, liquefaction, water-related effects, and problems
associated with the built environment). Alluvial fans pose several hazards: flash floods, debris flows, and
problem soils. Closed basin lakes extend their flood plains reoccupying their lake beds during wet cycles.
•
The Rocky Mountain and Colorado Plateau provinces are stable in comparison, but they have their
hazards too;
•
Colorado Plateau hazards include rockfall, river flooding, flash flooding, and collapsible soils;
•
Rocky Mountain province hazards include avalanches, landslides, debris flows, and river flooding;
Ties NATURAL HAZARDS of the GEOSPHERE to issues of social and behavioral science:
Anthropology: who was hurt…
Demographics: population at risk. Why are people where the greatest dangers are at?
Economics: http://desne.ws/yij95D Landslide east of Cedar City disrupts local economies east of
landslide.
Political Science: Acts of God.
Sociology: LDS leadership and preparedness
Psychology: Hazards versus risk.
11. The geosphere is the basis for geologic resources. Utah has diverse sets of geologic
resources, because of diverse rocks, because of rgionally-diverse geologic histories
A region's geologic past gives it its resources of the present. Utah’s three physiographic provinces have
had different geologic histories and therefore Utah has three sets of geologic resources: including coal from
swamps; sand/gravel from large lakes; minerals from diverse processes that mostly affected the basin and
range and into the rocky mountain province as broad west to east bands; gas and oil from rocks that once
were sediments of ancient seas and oceans that covered most of Utah; that the geologic past of Utah is
well-exposed and varied and brings us the red rocks of the Colorado Plateau with dinosaur tracks of the
Moab area and dinosaur bones of Vernal; it brings us the all the handsome, and yes, the more subtle
bedrock of our great State.
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PowerPoint.... review concepts of this chapter... with emphasis on Geologic Resources of UT.
Atwood-Utah-WhySoMineralRich
Tie Utah’s GEOLOGIC RESOURCES and the GEOSPHERE to Utah issues of social and behavioral
science:
Anthropology:
Demographics:
Economics:
Political Science:
Sociology:
Psychology:
FINAL SECTION OF THIS CHAPTER… So What?
How GEOSPHERE matters to the physical and human geographies of Utah.
Know where you are, know who you are. GeogUtah Mantra.
And be empowered to lead a good life… that’s the underlying assumption of UofU GEOG3600-Geography
of Utah.
Understanding leads to a sense of place… understand Utah, understand its foundation… the geosphere.
To “Think Like a Geographer of Utah”… see the web of relationships among Utah’s peoples, places and
environments. See the web of The 15 Words of GEOG3600… the matrix.
For the GEOSPHERE:
Connect GEOSPHERE and the 5 themes of geography… these are pretty straightforward… location…
place… interaction… movement/migration… and regions.
Connect GEOSPHERE and the 5 subsystems of Earth systems… that should be easiest of all. Systems, by
definition have subsystems that interact. As one of the five subsystems of Earth systems, the
GEOSPHERE is intimately associated with the other four.
Connect GEOSPHERE and 5 issues of social and behavioral sciences (anthropology, economics;
demographics; political science; and sociology)
LIST of “The 15 Words”
Loc
Place
Migra
Inter
Region
Geo
Hydro
Atmo
Bio
Anthro
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Econ
Demog
PoliSci
Sociol
QLife
SELF QUIZ
Know Utah’s three physiographic provinces.
•
Understand the basis for the boundaries (and boundary dilemas) of the physiographic provinces.
•
Memorize that: the geosphere largely determines Utah’s natural resources, natural hazards, and
scenery.
•
If you want to appreciate the geosphere, think: Materials, Landforms, and Processes.
•
All of Utah’s scenery results from (1) tectonics; (2) erosion / deposition.
•
All of Utah’s geologic resources result from the rock cycle… that is driven by (1) forces with Earth =
tectonics; and (2) forces on the outside of Earth = erosion / deposition.
•
Tectonics is the study of movements of Earth’s crust (the very outer skin of Earth). Crustal
movements within the North American plate result in many of Utah’s landforms and hazards.
SUMMARY:
Utah’s physical geography is underpinned by the GEOSPHERE. It directly controls topography, scenery,
natural hazards and natural resources.
To appreciate Utah’s geography, it helps to appreciate the Earth science that surrounds all Utahns:
materials, landforms and processes. Tectonics, plus the rock cycle, plus time equals Utah ’s geologic
resources, hazards, and scenery.
Utah is rich and hazardous geologically because Utah has three regions called physiographic provinces,
based on the GEOSPHERE, defined on the basis of landforms: the Basin and Range physiographic
province; the Rocky Mountain physiographic province and the Colorado Plateau physiographic province.
Coaching: don’t confuse Utah’s regions based on the geosphere (physiographic provinces) with Utah’s
regions based on the hydrosphere (drainage basins). The Basin and Range physiographic province
(geosphere) is not the same region as the Great Basin (hydrosphere).
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