From sand seas to sand
stones: Global data sets
and virtual exploration in
the classroom using
Google Earth
by Les Hasbargen
SUNY Oneonta
2014
Key Themes: Inquiry-based exercise
1. Students explore the world! (and planets…)
2. Students measure landforms
3. Students construct hypotheses and test
them--if data are available
● For sand seas, students discover size,
location, and shape
● Initial observations lead to questions about
stratigraphy and sandstone bodies from the
past...
Key Themes for Student Projects
In this exercise, students:
● Measure dunes and sand seas
● Attempt to decipher wind direction from
shape
● Tie dune shape and size to cross
stratification (this is an attempt! )
● Look at stratigraphy in regional cross
stratified sandstones (if imagery is available)
● Interpret the setting for the sand body
Learning outcomes/goals
• Learn how to use spatial data to measure
geologic features
• Develop critical thinking skills in comparing
modern to past dune environments
• Develop writing and report presentation skills
• Develop skills in collaborative investigation
Enter Google Earth...
● Global (and planetary) aerial imagery and
topography
● Students do need some training with
navigation, storage of user-created data, and
point-line-area creation in GE
● Students learn how to use screen captures
and develop annotation skills
● If there’s internet, pull up Google Earth...
Mongolia
● Can one determine thickness of the sand sea?
● Dune height can be measured.
● If cross-stratification scales with dune size, then x-strat is measurable
○ slip face slope = bounding surface?
○ set thickness scale with dune height?
○ dune asymmetry set by wind direction
○ foreset dip direction
Namibia
How might x-strat vary around this sand sea?
Can one use Hadley cell circulation to model wind patterns?
Where is the sand coming from?
Note that it may take a minute or two for the higher resolution
topography to be accessed--you can tell when dunes become visible
Afghanistan
Taklimakan Desert
What is the wind direction, based on
dune asymmetry?
Taklimakan Desert, north-south profile
Note that wedge-shaped
deposit, and ability of
sand to “climb to new
heights”
Taklimakan Desert, west-east profile
Note the variation in dune size
Note the wedge-shaped mass of sand
Cross stratified sandstones in the
US
● Glen Canyon Group
o
o
o
Navajo sandstone
Kayenta formation
Wingate formation
● Locations
o
o
o
o
Zion Canyon
Glen Canyon
Grand Canyon
Valley of Fire
Background for Dunes and Sandstones
●
●
●
●
●
, from National Park
Service, about the Navajo SS
http://offices.colgate.edu/bselleck/Geology120/NavajoB.pdf, very
nice summary with maps of SS extent in the
Jurassic
Current research list: Query results from
Astrophysics Database
Recent experimental dune growth
Dave Rubin
http://sed.utah.edu/Navajo.htm
o
http://www.nature.com/ngeo/journal/v2/n9/abs/ngeo610.html
o http://walrus.wr.usgs.gov/seds/bedforms/animation.html
● Wikipedia: http://en.wikipedia.org/wiki/Dune
More Online Geology
● Utah Geologic Map, 1:500K: needs to be
converted to online searchable map
● Geolex (USGS)
● I couldn’t find an easy, sortable, searchable
geologic map online (and problems with size
for a Fusion table)
● Take advantage of photos in Google Earth
Student created products
● Topographic profiles of dune seas, and eroded cross sections
of Navajo/Wingate SS showing thickness
● Screen captures of mapped extent
● Verbal descriptions of sand sea geometry and dune shape
● Statement about slip face orientation and dominant wind flow
direction
● Statement about sediment sources for the dune field
● Statement about conditions of formation for Glen Canyon
Group (Navajo ss, Kayenta formation, Wingate formation)
Assessment
● The topographic profiles need to have descriptive titles with
location; annotation on the profile and/or comments in a
caption which describe and interpret the profile.
● Sand sea descriptions should provide a sense of the extent and
rough estimate of thickness, along with the geographic setting
for the dune region; an estimate of dominant wind direction;
and an identification of the potential sources of the sand.
● Data collection and analysis can be ranked according to
excellent, good, fair, poor, unacceptable.
● Summarization can be ranked according to excellent, good,
fair, poor, unacceptable.
Work in Progress! I could use some
sedimentologic advice on this one!
● Better imagery of cross stratified cliffs would make this
project much more feasible
● Imagery should have a viewing direction and approximate
scale
● An online resource for on the ground imagery would be ideal,
either in Google Earth, or as a Fusion Table (looks like
Google Maps…)
● A clickable, searchable, filterable online geologic map of
Utah would also allow students to discover the extents of
sandstone deposits on their own
And a plug for one more thing…
See my teaching activity for this workshop
called
Meander Migration in the Amazon
In it, you’ll find links to Google’s Earth Engine,
with time series of Landsat imagery since 1984
http://serc.carleton.edu/NAGTWorkshops/sedi
mentary/SGP2014/activities/85513.html