3/18/2011 draft for UVU -Intro Geology – March 30, 2011 –

(needs... handout... and check CBHunt ref; print out handout

Genevieve Atwood, Ph.D., guest lecturer


LINK to EncyBritannica-BreakingWaveOffKanagawa - Hokusai ... Shorelines, Waves, Tsunamis... Japan in the news



Joy of Geology –

GEOSCIENCE the GLORIOUS ENTERTAINMENT -- LINK to UofU Students on Antelope Island

·      Recognizing shorelines of the past can be challenging (and rewarding, sometimes).

·      Recognizing components of shorelines (erosional versus depositional/constructional; delta surfaces versus shoreline evidence, etc) can give a sense of empowerment through understanding

Relevant... Japan, living on the shores of... .


THIS lecture assumes you already know about:

·      The Hydrologic Cycle (a.k.a. the water cycle). LINK to USGS schematic

·      The Rock Cycle – includes how sediments are products of sedimentation specifically… weathering, erosion, transport, and deposition LINK to ESE rock cycle animation


By the end of this session, you should:

·      Understand what shorelines are … (narrow definition and broad definition)

·      Begin to understand their variability… huge subject

·      Know where and how to look for shoreline evidence in Utah County and elsewhere in Utah.

·      Perhaps be able to imagine how “your” shorelines were formed.


So What? Shorelines are great places to “see” Earth systems…

the interactions of geosphere, hydrosphere, atmosphere (weather/climate), biosphere (living Earth), and anthrosphere (human footprint).


Roadmap of today’s session: (a) some terms; (b) some concepts of geology / Earth systems; (c) move from global to local, including some of my work on Great Salt Lake and Lake Bonneville.



TERMS... .

Narrow definition: shoreline is the intersection of two surfaces: (a) the surface of the water body, and (b) the surface of the land. LINK to GOOGLE Earth image of Utah Lake near UVU


From Merriam-Webster on-line:

 1the line where a body of water and the shore meet
2the strip of land along the shoreline


From Glossary of Geology, 5th ed., AGI iPhone ap (American Geological Institute):

(a) The intersection of a specified plane of water with the shore or beach; it migrates with changes of the tide or of the water level. The term is frequently used in the sense of “high-water shoreline” or the intersection of the plane of mean high water with the shore or beach, or the landward limit of the intermittently exposed shore. … (Synonyms…)

(b) The general configuration or outline of the shore. The terms “shoreline” and “coastline” are often used synonymously, but there is a tendency to regard “coastline” as a limit fixed in position for a relatively long time and “shoreline” as a limit constantly moving across the beach.


FIRST shorelines are associated with relatively large water bodies.

To have a water body… necessary factors… must have a place for water to be… and must have water.

Oceans - yes; Lakes - yes; … Ponds?

Global scene – Oceans (LINK to Norton-15.03 Global Coastlines; and LINK to Norton-15.03abc added relief and tectonics)


For purposes of this talk… NOT going to explore how the water body got there… and not how that-which-contains-the-water got there... there are several possible ways… tectonics, dams… can’t go there today… but never forget tectonics.




and how we talk about "shorelines" here … a shoreline = EVIDENCE of a SHORELINE

Evidence… what might it be? (a) topographic expression (shape, size, and slope); (b) materials; (c) all due to coastal process (waves, currents, biota).


VIRTUAL TOUR of SHORELINES… Who has been to a great shoreline… anywhere?

French Riviera? LINK GoogleEarth

Florida? LINK GoogleEarth

Hawaii? LINK GoogleEarth

Bear Lake? LINK Bowen

Lake Powell? LINK Hamblin

Utah Lake ? Southwest shore Google Earth; Pelican Point Google Earth; East by Provo Google Earth.


SHORELINES as landforms

LANDFORMS – are natural features on Earth’s surface with:

1.  Characteristic SHAPE

2.  Characteristic MATERIALS

3.  Characteristic PROCESSES that make them

And… all landforms have a history… they each tell a story (just like every rock has a story)


DIAGRAMS… for an ocean but similar processes

Cross-section of a depositional (accreting): LINK to Norton-15.15

Plan-view of shorezone… not Antelope Island… ocean with river: LINK to Norton-15.21

And 3-D of up-welling and down-welling along shore: LINK to Norton-15.10ab


Field Guide to Shorelines... what to look for


LINK to HUNT sketch of Bonneville Shoreline LINK to Hamblin image of Point of the Mountain.

SHAPE: Virtually horizontal.

  • They follow the same elevation contour around hillslopes and into drainages.
  • They represent a significant water level… such as sea level, or the outlet of a lake, or a long time that a lake has stabilized.
  • Often they consist of two slopes: (1) a steeper slope where waves run-up the shore, and (2) a nearly-flat surface where the waves break across a beach and spread sediments across a flat surface.


MATERIALS: Sediments

NOT like a RIVER... NOT like a deposit from a flash flood


PROCESSES: Erosion / deposition.



    • Active shores, meaning an existing shoreline: look for the interface between the land and water.
    • Depositional features = beaches, lagoons, deltas, spits, bars.
    • Erosional features = sea cliffs, pocket beaches, sea arches.



    Importance of shorelines… globally

    Scenery - yes

    Hazards – yes

    ·        Norton15.35a; Norton15.35b; -- Atlantic / Gulf coast … Note: erosion and depostion are a couplet.

    ·        USGS links among others:

    Resources – yes – particularly if one counts recreation (beaches) and ecosystem.      

    ·        SFBay, example:

    Science – yes

    ·        Why? Interfaces interest scientists… where change happens…

    ·        East coast, continental shelf – LINK to Norton-15.05 NewEngland


    Importance of shorelines… locally…

    Great Salt Lake and Lake Bonneville


    Scenery – yes – particularly if you appreciate the subtlety of the Basin and Range. LINK to Hamblin


    Hazards – several… of GSL and of paleo-shorelines of Lake Bonneville because steep.

    ·        For example, this landslide in Lake Bonneville sediments, Weber County:

    ·        And... Sherwood Hills landslide studied by UVU undergrads on topography steepened by Lake Bonneville shore processes LINK to UVU undergrad poster by (Paul Gardner, Robert White, Jessica Oxford, Victoria Sailer, Adam Healey (Michael Bunds), 2008). The "bad-actor" bedrock is the direct cause of the ground failure, but the slope, oversteepened by Lake Bonneville coastal process probably contributes to instability.


    Resources – important –

    ·        shoreline sand and gravel… for constructions LINK to Hamblin Point of Mtn

    ·        benches for building sites, for example UofU, BYU, WSU, parts of USU, on shoreline features of high levels of Lake Bonneville… and UVU, too, on delta deposits. LINK back to UVU image from GoogleEarth shown before... look at all the construction.


    Science –

    ·      Great Salt Lake – Lake Bonneville system is The Best historian of climate change of interior continental North America (some bias there). LINK to UofU Students Holocene shorelines


    Let’s go "collect" some shorelines

    CB Hunt "collected" mountains... every kind he could find (LINK). Let's collect some shorelines, such as:  

    1.  Modern shoreline of a fresh water, shallow lake … What is special about Utah Lake?

    2.  Shoreline evidence of the past… Can you see through the haze, into the distance and recognize shorelines of Lake Bonneville on the west side of Utah Lake?

    3.  Active deltas of Utah Lake … may be impossible to see.

    4.  Deltas of past… trick question unless you recognize the obvious.