Death+Valley

= -- DEATH VALLEY= =** --- By Chloe Wong, Reed Walker, and Liam DeFazio - **= media type="youtube" key="ZqXN26VJ1j0" height="229" width="288" align="center"

= Introduction:= Death Valley is located in Sierra, Nevada in the Mojave Desert 8. It is the lowest and driest point in the northern hemisphere, as well as the home to over 10,0000 species 8. It has many land features but the "must see" features include: the large salt pan, a basin range sculpted by run-off, dunes, and the bad waters (the lowest point) 8. As seen from the topographic map of Death Valley below, the concentration of lines on the sides of Death Valley makes for an extremely steep slope formed from the surrounding mountains and lowness of ground at 282 ft. below sea level. 9 In addition, the v-shaped contour lines signify the runoff that occurred millions of years ago when Death Valley was just beginning to form.



=** -- Geologic and Setting:**= The agent of erosion that formed Death Valley is running water. It is great example of a basin and range landscape 3, which forms as a result of a normal fault with a tensional pressure and multiple alluvial fans that repeatedly approach and erode the lower surface of the foot wall and evaporate (//see figure below//) 3. The way the footwall rises over the head wall creates a steep slope well suited for runoff erosion 1. Additionally, this type of erosion was susceptible because the soil was made of mudstone 8, a clastic sedimentary rock that is formed through cementation and compression of a fine grained material, like clay or silt. This weak, fine grained sediment could be easily eroded, carried down and loosened by run off, therefore, sculpting the mountains and irregular ridges of Death Valley. The effects of running water erosion can be seen at the sharp peaks of **Zabriskie Poin**t 8 (//see figure on right//). Water erosion also created rills, many of which eventually deepened and became gullies. Death Valley is also known for its salt pans, which formed through the evaporation of prehistoric lakes or alluvial fans. Once the water was fully evaporated, salt along with other dissolved minerals in the waters were left behind. Overtime, the concentration of salt increased, leaving a salty "soup" that eventually dried to create the **salt pans** 8. In the salt pans there are also amazing salt pinnacles. **Salt pinnicles** are caused by the wind drawing up tendrils of salt 3, creating salt formations similar to stalagmites. They grow about an inch each year, and can be eroded by the wind as well.

In addition, Death Valley has hosted several violent volcanic eruptions. The largest of these explosions resulted in the massive **Ubehebe crater** 2. The crater is half a mile wide, and is an estimated 2000-7000 years old 2. The Ubehebe Volcano exerted a massive pyroclastic surge called a base surge. During which, a gigantic column of debris was hurled upwards, leaving the massive crater.



One incredible example of multiple forms of erosion and tectonic activity is **golden canyon** 2. At the entrance, there are many alluvial fans that form due to an ephemeral stream caused by immediate rainfall from the tops of the mountains and erode then transport sediment. Overtime, the alluvial fan will "bake" or evaporate, leaving behind the sediment it transported. In addition, there are several sporadic boulders and cobbles, which were dropped after being carried by water during floods. The law of original horizontality states that sediment is deposited in horizontal layers overtime. However, in the canyon these layers are tilted by tectonic movement, causing the bands of sediment to appear folded and vertical. Near the top of the canyon lies fine grained sediment composed of sand and silt (also known as mudstone, described above). The reason for this excess of fine grained sediment is that the area used to be covered by lakes. In the mudstone, softly undulating ripple marks attributed to the erosion by waves in the lakes. There is also some till and erosional features on the canyon attributed to the glaciers that covered death valley during the Pleistocene ice ages 8. At the very top is the "red cathedral" rock 8, which is sculpted into peaks by run-off along with the mudstone.



Death Valley lies on top of one of the largest aquifers in the world. In fact, it empties into this water system at a point called **devil's hole 1 **, which is an underground cavern and pool fed by the aquifer. Within devil's hole, a flowering aquatic system exists with many different species of animals. 10

=
The **Eureka Dunes** range from 3 miles long and 1 mile wide and rise 680 feet 9 from Death Valley's ground. They are an example of the agent of erosion wind. Because Death Valley is a desert, there are many loose particles that can be deflated, or picked up by wind. The wind will come in contact with an obstruction, most likely the mountains, that decreases the wind's velocity and cause it to deposit the particles of sediment creating a dune.======



= = = = = = = = = =

=** -- Climate and Weather:**=

In June of 1913, Death Valley reached the temperature of 134 F or 57 C 2, which made for the second highest recorded temperature in history. It is common for Death Valley to have years where there is no rainfall at all, and never has there been more than two inches of rain in a year 2. Clearly, Death Valley is notorious for its extremely dry and hot conditions.

The driving source behind these conditions is the orographic lifting. Because Death Valley is surrounded by mountains, any air pockets, especially those that are humid, will encounter the windward, or wet side, of mountain which acts as a barrier, causing the air pocket to rise. As it rises, it will cool adiabatically, meaning that the air pocket will cool and expand due to lessening of air pressure in the atmosphere as it rises. This will decrease the capacity and saturation point of the air pocket so that precipitation must occur in the form of rain or snow. By the time the air pocket reaches the leeward side, or dry side of the mountain, the air pocket will have already lost a good amount of vapor water and will compress. This causes a dry environment because the leeward side will receive only dry air pockets and there will be a low chance of precipitation. . Death Valley and all around the world there have been hotter than normal temperatures due to global warming, the excessive omission of carbon dioxide, methane, and other gases that cause an enhanced greenhouse effect so that the sun's heat will be trapped within Earth longer. Overall, this causes the climate in Death Valley to be hotter than norm, which affects the wildlife who rely on the specific temperature of Death Valley. The average length of the day in Death Valley is 14 hours 34 minutes. 8 Death Valley's latitude is 36.15 degrees N. 2 Being close to the Tropic of Cancer (23.5 degrees latitude), it has longer days during the Summer Solstice (June 21) and shortest days during the Winter Solstice (January 21). This is because during the Summer Solstice Earth's 23.5 degree tilt makes the Tropic of Capricorn receive sun rays that are perpendicular. This high concentration of sun's energy makes it hotter than normal and the sun's path during the day to last longer. Conversely, the Winter Solstice receives a low angle of the sun's rays, and therefore, the intensity of the sun's energy is at its least and the sun's path during the day is short. In the temperature graph above, this pattern can be seen because June through September is when the temperature is at its peak and from December to January the temperature is at its lowest.

= --- Biome:= = =

=
The coolest month is January, which ranges from about 38- 69 degrees Fahrenheit. 3 The hottest month is July, which ranges from 88 to 115 degrees Fahrenheit. 3 In the night, temperatures drop about 20-30 degrees 3. However, the days are blisteringly hot, in fact, the second highest temperature ever recorded on earth was found in death valley at 134 degrees 3. It is also one of the most dry places on earth, with an average 0 to 5% relative humidity 3. Such harsh conditions qualifies Death Valley as a desert biome where over 1,000 different types of plants 8 .======

=
The plants have adapted to be able to survive in the desert. Some have root systems that extend over 30 feet underground or are very widespread in all directions, making it possible for the plants to get more water. 3 Although life higher then the microscopic level does not exist in the salt pan, plants exist around the marshes and springs======

=
at it's edges. These plants include Pickelweed and Salt Grass, which have adapted to become tolerant to salt. 3 Cactus is abundant around the northern alluvial fans of the valley, which have a. There are also a variety of desert wildflowers that grow during spring rain.======

=
In terms of animals, for the most part, they are small, nocturnal creatures 3. These characteristics help these creatures survive by avoiding the sun, since at night it is tremendously cooler and being small allows them to bury in good hiding spots to escape the heat.====== ==

=
There are many lizards and few snakes 3. These creatures are cold-blooded animals, which means they rely on the sun's heat to survive because they do not possess any internal mechanisms to regulate body temperature. In addition, they have adapted to this environment because they have grown sharp claws that help them to dig and bury themselves when the sun becomes too hot.======

=
There are also many types of rodents, including rabbits, Desert Wood Rats, Kangaroo Rats, and Antelope Squirrels that are prayed on by coyotes, foxes, and bobcats. The largest animal that lives in this region is the Desert Bighorn Sheep. Their long, massive legs and sturdy built help them to adapted to this climate because they are able to clime to higher elevations where it is cooler to escape the heat. The plants and animals of Death Valley are well suited to their environment. They preserve water effectively and can function in the immense heat. Some are well suited for the flat salt pan, while others such as the Bighorn Sheep have hooves with traction for climbing Death Valley's mountains and steep slopes.======

= = = = = =

= = = = = = = = = = = = = = = = = = = = = =

= = = = = = = = = = =** --- Human Impact:**= media type="youtube" key="R_dP4ENjcL0" height="305" width="383" align="center"

Death Valley is in a desert biome, with an average of less than two inches of rainfall. Therefore, the majority of Death Valley's water supply comes from its confined aquifer. A confined aquifer is an underground water supply contained between two impermeable layers of sediment. However, areas around Death Valley including Las Vegas, overuse the aquifer. Water from the aquifer is slowly running out, and affecting the many species that live in Death Valley. Also, natural springs attract a great amount of people, who overuse the water. The eventual lack of water would devastate Death Valley's plant and animal life. Contamination and fluctuation of water levels also gravely influence the animals that live in the aquifer-fed pool in devil's hole, such as the pupfish. There are less than 200 in existence and are rapidly depleting because of aquifer contamination and overuse. The water is being contaminated by point contamination such as septic leaks, causing immense damage to the water supply and habitat. = = = = = = = =

= = = - Resources:= 1. "3. Basin-Range Faulting." //Saguaro Juniper Corporation//. Saguaro Juniper Corporation. Web. 08 June 2010. < [] >.Crossley, John. //2.// //Death Valley: America's Outback (Death Valley National Park, Shoshone, Tecopa)//. Death Valley Chamber of Commerce, 2008. Web. 09 June 2010. < [|http://deathvalleychamber.com/history.php.] >. 3. "Death Valley National Park: Description (DesertUSA)." //Desert Biomes by DesertUSA//. DesertUSA.com and Digital West Media, Inc., 1996. Web. 09 June 2010. < [] > 4. "Ubehebe Crater, Death Valley National Park, California." //The American Southwest - Arizona, California, Colorado, Nevada, New Mexico, Texas, Utah, Wyoming; Slot Canyons & Travelogue//. Web. 08 June 2010. < [|__//http://www.americansouthwest.net/california/death_valley/ubehebe_crater.html//__] >.Demand Media, Inc. 5. "Google Image Result for __Http://www.topozone.com/map_get.asp?z=17&e=649666.450309537&n=4469769.0461726//__//."// Google//. Demand Media, Inc, 1999. Web. 08 June 2010. . 6. "Google Image Result for __Http://virtual.yosemite.cc.ca.us/ghayes/images/DSC08068//__ //Salt Pinnacles B.JPG."// Google//. 2007. Web. 08 June 2010. . 7. "Google Image Result for __Http://www.pangaeaproject.com/images/ZabriskiePointDeathValley.jpg//__//."// Google//. Pangaea Project, 2007. Web. 08 June 2010. ."NPS: Explore Nature » National Natural Landmarks. 8. " //NPS: Explore Nature//. National Park Service U.S. Department of the Interior, 27 Apr. 2010. Web. 08 June 2010. < [] >. //9. Death Valley: America's Outback (Death Valley National Park, Shoshone, Tecopa). Death Valley Chamber of Commerce, 2008. Web. 09 June 2010. .// 10. "YouTube - Death Valley National Park/Badwater Basin - August 28, 2007." //YouTube - Broadcast Yourself.// UnknownWI, 26 May 2008. Web. 08 June 2010. < [] >. 11. "YouTube - NATURE | Life in Death Valley | Devil's Hole Pupfish | PBS." //YouTube - Broadcast Yourself.// PBS, 6 Sept. 2009. Web. 10 June 2010. .