Pathological Geomorphology

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    The Barbie Fan: A pathologically perfect Nevada alluvial fan

    8-26-2010_3-57-26_pm

    The state of Nevada has more fans than Las Vegas has foreclosed properties (that's a lot). This particular fan was termed the 'Barbie' fan by my co-author and UNLV colleague Brenda Buck. The name is appropriate because the shape is almost too ideal. We mapped most of the Barbie fan as part of the Ivanpah Valley Mapping Project (the Ivanpah-viathan). 

    The fan does have an ideal fan shape. It is also comprised of an elaborate assemblage of Quaternary alluvial surfaces of a broad range of ages, thus further substantiating its Barbie-ness. (see, for example, the paper about the Cedar Creek alluvial fan in Montana...this paper was a field camp staple when I used to run a course on fans in eastern Nevada). Here are links showing different characterizations of the geology of the Barbie Fan:

    http://geofroth.posterous.com/the-ivanpah-megamap-in-kml-form

    http://geofroth.posterous.com/nevada-geo-flood-hazard-map-in-kml

    The Barbie fan is fed by a drainage that cuts right through the Lucy Gray Mountains. It obliquely straddles the border with California, and its outermost point creates a divide between two dry lakes where the fan grazes the southern extremity of the Spring Mountains. The 'lake' to the north (Roach Lake) is entirely in Nevada and the 'lake' to the south (Ivanpah Lake) is about 99.9% in California. The divide now hosts a casino and outlet mall complex (and a roller coaster....Nevada, remember?). The border runs through the parking lot. 

    Take a look at the recent drainage courses on the fan and appreciate how a relatively small change in the position of a major distributary channel could convey a flood entirely to either state, or both. A dilemma for water lawyers, possibly. Certainly a potential dilemma for the major airport that has been planned (now on hold for economic reasons) to span the entirety of Roach Lake (yes, that is right, a major airport...Nevada, remember?). Note that Las Vegas is not too far away...just up I-15 about 35 miles.

    http://www.flashearth.com/?lat=35.59174&lon=-115.363046&z=10.7&r=0&src=msa

    8-26-2010_4-18-11_pm

    • 26 August 2010
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    almost 2 years ago Joe Cook responded:
    Joe Cook
    Ah yes, the Ivanpah Valley. I did my thesis on this fan and some other to the north in your "eolian causeway". Basically we demonstrated that there is a relief threshold to eolian sand transport via saltation across alluvial fans. The reason you see a sandy apron across the lower reaches of the Lucy Gray fan is low relief fan channels allow saltation to proceed across the fan. Further up on the fan, where drainages are more deeply incised, sand cannot proceed. Saltating grains become trapped in the deeper channels rather than continuing across the fan. The pavements in this area also demonstrate this phenomenon. Pavements higher on the fan are strong and well-varnished. You don't see well developed pavements lower on the fan as they are inundated by eolian sand deposition.

    I took my wife out to do field work one December while I was in school. We froze camping out on that fan within sight of the flashing lights of Primm. We made coffee through a sock in the morning (no proper filters) and stayed at the hotel the next few nights. Incidentally, that roller coaster is probably the scariest I've ever been on mainly because you convince yourself you are going to die while riding it.

    almost 2 years ago Kyle House responded:
    Kyle House
    Joe,

    Thanks for the interesting details.

    Do not forget that the toe of that fan is where you and I had our first (and only?) meeting in person...I recall that you wife was there as well. Same December, possibly...pretty sure it was.

    over 1 year ago Rob responded:
    The Barbie Fan is soon to be no more - it is the site of the Silver Stae PV Project. Good-bye fan and good-bye tortoises.
    9 months ago Andrew Hammonds liked this post.
    9 months ago Josiah Gardiner liked this post.
    9 months ago jeremiahfortner liked this post.

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