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Death Valley Alluvial Fans


Death Valley Alluvial Fans
Photo Information
Copyright: James Parker (Jamesp) Gold Star Critiquer/Gold Note Writer [C: 1369 W: 9 N: 6334] (18906)
Genre: Landscapes
Medium: Color
Date Taken: 2006-03-02
Categories: Desert, Mountain
Camera: Canon EOS 1Ds MkII, Canon 24-70 mm f 2,8 L-USM
Exposure: f/10.0, 1/400 seconds
More Photo Info: [view]
Photo Version: Original Version
Date Submitted: 2008-12-11 11:51
Viewed: 4527
Points: 28
[Note Guidelines] Photographer's Note
Today's posting was taken from Dante's Peak. It is a fairly 'classic' view of Death Valley. What this shot shows, apart from the salt flats and mountains are some excellent alluvial fans at the base of the mountains.

An alluvial fan is a fan-shaped deposit formed where a fast flowing stream flattens, slows, and spreads typically at the exit of a canyon onto a flatter plain. A convergence of neighboring alluvial fans into a single apron of deposits against a slope is called a bajada, or compound alluvial fan.

Owing to the flow as stream gradient decreases, coarse-grained solid material carried by the water is dropped. As this reduces the capacity of the channel, the channel will change direction over time, gradually building up a slightly mounded or shallow conical fan shape. The deposits are usually poorly-sorted. This fan shape can also be explained with a thermodynamic justification: the system of sediment introduced at the apex of the fan will tend to a state which minimizes the sum of the transport energy involved in moving the sediment and the gravitational potential of material in the cone. There will be iso-transport energy lines forming concentric arcs about the discharge point at the apex of the fan. Thus the material will tend to be deposited equally about these lines, forming the characteristic cone shape.


Alluvial fans are often found in desert areas subject to periodic flash floods from nearby thunderstorms in local hills. They are common around the margins of the sedimentary basins of the Basin and Range province of southwestern North America. The typical watercourse in an arid climate has a large, funnel-shaped basin at the top, leading to a narrow defile, which opens out into an alluvial fan at the bottom. Multiple braided streams are usually present and active during water flows.

Phreatophytes are plants that are often concentrated at the base of alluvial fans, which have long tap roots (30–50 feet) to reach water. The water at this level is derived from water that has seeped through the fan and hit an impermeable layer that funneled the water to the base of the fan where it is concentrated and sometimes forms springs and seeps if the water is close enough to the surface. These stands of shrubs cling onto the soil at their bases and over time wind action often blows away sand around the bushes which form islands of habitat for many animals.

nglen, Dis. Ac., eqshannon, siggi, pekkavalo1, jaycee, boreocypriensis, CeltickRanger, Adanac, ramthakur, albert, ferranjlloret has marked this note useful
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ThreadThread Starter Messages Updated
To ramthakur: BelowJamesp 1 12-11 23:44
To Adanac: VisitingJamesp 1 12-11 23:15
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Critiques [Translate]

  • Great 
  • nglen Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 2883 W: 30 N: 9683] (36145)
  • [2008-12-11 12:19]

Hi James. Your pasport must be full with stamps.
Once a beautiful compostion. From this high POV. Looking over the salt flats. Then up to the mountains with the snow just catching the sun. Interestin reading about the Alluvial fans . TFS.
Nick..

Hi James,

Very good composition with beautiful colours.

Gert

I have driven across Death Valley with a 1963 Pontiac and no air conditioning..I think I remember it being about 120 that day....one of the worst and most scary days of my life in driving...

Your image brings me some memories of the salt Lake Flats...just in appearance though and from a distance....I am afraid of spiders, but I can look at images of them...but I don't like the real desert at all..and it is even hard for me to look at the image...serious....not sure why..perhaps because I am 180 degrees opposite..I love mountains, trees, streams and such...I'll leave the hot and dry to Jane Magen:-) good shot techincally...
Bob

  • Great 
  • siggi Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 3097 W: 109 N: 12399] (52850)
  • [2008-12-11 13:14]

Hi Manuel
What great colours and composition. I love the mountains and it is great to see them like this. winter can bring out the best and worst in them but.
Regards Siggi

Hi James,
Very beautiful landscape picture; great POV and composition, very good DOF (with f/10!), nice colours. I like the composition of high bank on back and front and the sharp details that seem to start right from the front and continue forever to the mountains. I knew that 24-70mm L lens is excellent, now it looks even better.
TFS
Pekka

  • Great 
  • jaycee Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 2454 W: 10 N: 8044] (25460)
  • [2008-12-11 17:18]

Hi James,

I learn something from you with every picture you post. I will admit to my ignorance - I never knew what an alluvial fan was. I understand now thanks to your descripiton and clear example. I've never been to Death Valley even though it is in my neighbor state so really enjoy seeing the salt flats and wonderful mountains.

Jane

hello James

beautiful landscape image of desert and mountain,
with very fine POV and DOF, excellent sharpness and details,
i love to see that in the background's blue toned mountains
and sky there is a little place with white snowed colour, TFS

Asbed

Hi Big Brother James, an excellent landscape capture of these alluvial fans at the base of the mountains. Great details and very informative notes too.
TFS and cheers,
Bayram

  • Great 
  • Adanac Gold Star Critiquer/Gold Note Writer [C: 1273 W: 1 N: 6188] (21378)
  • [2008-12-11 18:29]
  • [+]

Hello James,
Splendid image James it makes me wish I had taken the time to go there when we were so close. Great work, thank you for sharing.
Rick

A grand view of Death Valley in its most impressive aspect, James. You have chosen the perfect point of view for showing us not only the salt plain but also those alluvial fans at the base of the mountains opposite you. There must be some below where you stand, I guess.
This is a great image you took more than two years ago.
Thanks and regards.
Ram
PS: Sorry for being irregular on TN; leaving the current job and busy winding up.

Hello James,
Great capture with very good details of this deadly landscape.
I like your DOF showing all details of both alluvial fans, white peaks and white salted pan.
I also appreciate the quality of your notes
TFS
Albert

Hi James,
Espectacular vista de éste valle aluvial, da gusto viajar a través de la web. Gracias por compartir (TFS) Saludos cordiales. Ferran

Hi James!

A wonderful photo of such an amazing subject. This is what I like in your shots, there's always a subject that looks great, has some very interesting facts about and most of all no one else will show it, they are always some special locations. We can always learn much from your posts. Never heard about these fans nor how they become. So TFS and for the notes ;)

Best regards,
Andor

Hi James,
What a stunning vista. This top down view on the salt flats gives it a perfect idea of the huge size. But, I really like the view on the mountain. The dry river beds/flows are amazing and probably does give an indication of how it once was. The repetition of the white of the snow is great.
TFS,
Niek

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