Week 7 – Death Valley
Artist’s Drive
(Photo by Tom Bean, NPS.) (Photo from NPS archives.)
At the Artist’s Drive stop, a photo from the gallery shows the beautiful multicolored rock formation from the Miocene epoch. Much of the coloring of these rocks come from Desert Varnish. Desert Varnish is a deep red/brown or grey layer on rock surfaces that darkens and thickens with age. This results from microbial life processes that put a thin layer of clays and manganese oxide minerals on the rocks (USGS Glossary, 2016). I would like to know how the thickness of this layer relates to the amount of time this rock has been exposed. I would then carefully look at the desert varnish on these rocks to then try to determine the amount of time between floods and sediment layers. By mapping out the time these rocks have been exposed maybe I could see a change in the extremity and frequency of floods upon the landscape of this area.
Furnace Creek
(Photo by M. Moreno, USGS)
At the Furnace Creek stop, a photo from the gallery shows a seemingly impossible desert oasis. This desert oasis has attracted people as well and they built an incredible lush golf course, hotel, and resort. The water in the aquifer was supplied during the Pleistocene ice ages. This was a time where the climate was much cooler and wetter than it is today. This aquifer is where surrounding cities such as Las Vegas are getting their water from. Las Vegas is growing at 6,000 people per month, which makes it one of the fastest growing cities in the United States. I would like to know the amount of water that is left in the aquifer and the average rate in which it is naturally replenished per year with water. I would then like to know what the average amount of water that is needed per person. I would use this information to attempt to see what the holding capacity of this area was due to the limited fresh water supply. I would then try to extrapolate keeping the same rate of population growth, when will the aquafer go dry and become unable to provide its residents with any water.
Zabriskie Point
(Badlands topography. Photo by Paul Stone, USGS.)
At the Zabriskie Point stop a photo from the gallery shows a bone-dry land incredibly sculpted by water. It is amazing how an area that seems the furthest removed from any form of water can be so shaped by it. These badlands were formed in a prehistoric lake and thus built on a foundation of mudstone. Mudstone is soft yet does not let water penetrate the surface to go down into the aquifer below. I would like to know how thick this layer of mudstone is. The water has cut deep grooves into the ground due to very intense yet sporadic rainfall this area receives. If I found out the thickness of the mudstone and the rate of erosion due to the rainfall I could figure how long it would take to erode through this impermeable layer to then allow water to penetrate the ground beneath it and help supply a possible aquifer below. Though if it is too thick then the likeliness of the ground holding water is less likely due to the pressure that the lower rocks are under. The USGS states that the badlands are the ultimate result of nature’s way of efficiently moving lots of water quickly (USGS, 2016). If we found out how much water these structures dissipated properly then maybe we could use that information to model structures to help dissipate water quickly from easily flooded urban areas.
Thank you,
Will
Resource:
US Geologic Survey. (2016). Death Valley National Park Virtual Geology Field Trip.
Retrieved from https://geomaps.wr.usgs.gov/parks/deva/devaft.html
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