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This video covers Eolian (aeolian or desert) processes, deposition, sedimentary structures, and stratigraphy. We start with classification of eolian environments, which include deserts and semi-arid regions, beaches and sabkas, sandy river banks, and periglacial regions. This lecture is focused on deserts dominated by sand dunes and ripples. I go over the global distribution of deserts and the coriolis effect, then we jump into the types of grain transport in eolian systems. Grains can be transported by wind the same way they are transported by water, by suspension in the air, bouncing along the ground or saltation, or rolling along the ground which is called creep. Because of this differential transport of sediment grains depending on grain size, this sorts the grains, so that the grain sizes are very uniform after having been heavily eroded and transported a long way. Wind heavily erodes sediment by deflation and abrasion. Bedforms in deserts include sand sheets, ripple marks, dunes, and draas, which can be preserved in the rock record as sedimentary structures. Then I go over the types of dunes, the differences between dunes and ripples, the differences between dunes and draas, what sand sheets are, what loess is (eolian silt), how dust is transported accross the world, and why mountain belts lead to rain shadow desert regions. We also cover how dunes form and the morphology of dunes, including the stoss side, the lee side. I also go over the common facies adjacent to desert facies, such as playa lakes, alluvial fans, & fluvial systems. Lastly, we go through the preservation of desert sediments in the rock record, the stratigraphy distinctive of eolian facies, and other hints we can use in the rocks to recognize what type of eolian environment formed the rocks we are looking at (i.e., eolian vs fluvial-eolian vs beach eolian).
References:
Depositional Sedimentary Environments: amzn.to/3kutTso
Facies models 4: amzn.to/3Fp5v3B
www.geol.umd.edu/~jmerck/geol...
GEO GIRL Website: www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, and donate to support the channel if you'd like!)
0:00 Types of eolian environments?
1:27 Sediment transport in eolian systems
2:29 Wind erosion in deserts
3:07 Desert bedforms
3:47 Ripple & dune formation
4:31 Types of dunes (morphologies)
5:26 Dras
5:43 Sand sheets and dust /loess
6:40 Global dust transport?!
7:09 Eolian facies distribution
8:22 Eolian deposit preservation
9:33 Eolian dune stratigraphy
10:54 Eolian vs. fluvial eolian stratigraphy
12:00 Eolian vs. beach stratigraphy
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Non-textbook books I recommend:
Oxygen by D. Canfield: amzn.to/3gffbCL
Brief history of Earth by A. Knoll: amzn.to/3w3hC1I
Life on young planet by A. Knoll: amzn.to/2RBMpny
Some assembly required by N. Shubin: amzn.to/3w1Ezm2
Your inner fish by N. Shubin: amzn.to/3cpw3Wb
Oxygen by N. Lane: amzn.to/3z4FgwZ
Alien Oceans by K. Hand: amzn.to/3clMx1l
Life's Engines: amzn.to/3w1Nhke
Tools I use as a geologist/teacher/student:
Geology field notebook: amzn.to/3lb6dJf
Geology rock hammer: amzn.to/3DZw8MA
Geological compass: amzn.to/3hfbdLu
Geological hand lens: amzn.to/3jXysM5
Camera: amzn.to/3l6fGRT
Image sources:
geology.isu.edu/Alamo/devonian...
doi.org/10.1144/EGSP25.03
officersiasacademy.blogspot.co...
myweb.facstaff.wwu.edu/talbot/...
smallpond.ca/jim/sand/migrati...
www.geol.umd.edu/~jmerck/geol...
www.researchgate.net/figure/D...
tamsilttrekking.com/dunes-oasi...
www.amazon.ca/Facies-Models-R...
giphy.com/gifs/headlikeanoran...
giphy.com/gifs/stunninglink-y...
omega7geo.wordpress.com/2013/...
www.geocaching.com/geocache/G...
www.slideshare.net/wwlittle/e...
www.geol.umd.edu/~jmerck/geol...
www.paperhi.com/Toplist_Best_2...
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