15 Landscapes Formed By WIND

Physical Geology Virtual Field Trip 2020-2021

Sand Dunes Shouldn’t Exist (Here’s Why They Do)

White Sands National Monument (at 3:00 is a brief mention of it in this video) hosts the most consequential dune field in New Mexico.  It is worthy of individual study due to its composition of gypsum, rather than the typical quartz.

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Figure 2.

There is the smaller Rio Salado Dune Field in central Nex Mexico, with the seasonally-dry Rio Grande riverbed providing the source of these sands.  Interestingly in this report, the heavy mineral suite is more typical of crystalline rocks (Evans, 1963), perhaps owing to intrusive and extrusive igneous rocks and metamorphic rocks in the Rio Grande watershed.

Other nearby sandhills are found south of New Mexico, near I-20 are the Monahans Sandhills, southwest of Odessa, TX.

North of New Mexico, in Colorado are the Great Sand Dunes National Park and Preserve, northeast of Alamosa, Colorado with the stunning Sangre de Cristo Mountains in the background.

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Sources (More to be added):

George C. Evans, 1963, GEOLOGY AND SEDIMENTATION ALONG THE LOWER RIO SALADO IN NEW MEXICO pp. 209-216 in Socorro Region, Kuellmer, F. J.; [ed.], New Mexico Geological Society 14th Annual Fall Field Conference Guidebook.

Sand Dunes Shouldn’t Exist (Here’s Why They Do)

Amongst the Sand Dune areas I wish to visit (or revisit) include the Great Sand Dunes National Park, White Sands National Monument (again) to begin with.

How Does the Wind Shape the Landscape?

Living in the Chihuahuan Desert for 14 years and traveling through the other three North American Deserts (Mojave, Great Basin, and Sonoran) between 1973 and 2017 gave me a good insight into eolian processes.

The four North American Temperate Deserts, in the Western United States and Northern Mexico, are due to the Rain Shadow Effect and their being within the Mid-Latitude High-Pressure Zone.

What a Geologist Sees - Part 36 - The Navajo Sandstone

[A minor disclaimer - I am not 100% sure that this is the Jurassic Navajo Sandstone, there are other eolian sandstones in southern Utah, but I am going with the assumption that this is Navajo.]

This "wow" photo was taken earlier this summer by a couple from our church while they were on vacation in Colorado, Arizona, and Utah.  They were kind enough to give me copies of their photos for educational use (and those will be captioned and attributed).  As my budget and schedule doesn't permit such excursions, I am grateful for their photos - past and present.  This is their first "digital trip", as past trips have been photographed on 35-mm film, necessitating scanning of prints or slides. 

The above photo was taken along Utah Scenic Byway 12, somewhere near Zion National Park.  This couple - Bob and Jenny - are very good about creating scrapbooks and logs of their travels and collecting all sort of info from the National, State, and local parks that they visit.  But sometimes it is some of the "in-between" photos that are hard to locate (or else I can't find the same scenes photographed by other people - for ID purposes).  I have several other great photos (for educational purposes) of the Navajo Sandstone.

This is another of their photos from this year, of "Checkerboard Mesa" in Zion National Park.  An image of Checkerboard Mesa used to grace the cover of one of the Physical Geology lab manuals we used to use.

This photo from Upper Antelope Canyon (from a scanned negative) is from a previous western trip.

Though I haven't visited any outcrop areas of the Navajo Sandstone for years (decades), from my past photos and newer photos given to me, I would have to say that the Navajo Sandstone is my "favorite" sedimentary unit for photographic purposes. I don't know of any fossil-laden areas of the Navajo, it is the large-scale eolian cross-beds that make for great photographs and educational teaching tools.

[BTW, for fossil-collecting purposes, I would have to say that the Eocene Ocala Limestone (and similar-aged units in Georgia) is my favorite sedimentary unit.]