Death Valley National Park死亡谷国家公园
死亡谷位于南加州东北部大约350公里处,1994年10月31日美国府将其设置为国家公园。虽然它拥有一个相当令人惊悚的名字,然而此地却是美国着名的爱德华空军基地和太空实验的场所,拜沙漠地带终年不断的强风所赐,高科技的风力发电产业更在此蓬蓬勃勃的发展,而令人赞叹的是沙砾地质奇观也成为此地最大的特色,而因为气候炎热的关系,吸引各地的游客前来亲身体验它的炙热,此地还曾经于1913年7月10日,创下57℃度的西半球高温记录,尽管如此,死亡谷依旧迷人,因为就是让人几乎失去空间感和时间感的错觉,沧海桑田、物换星移的变迁,更能让人感受死亡谷生与死交融的魔力!
干燥气候,生命依然在此繁衍
死亡谷每年的降雨量只有1.9寸,这个稀少的水量主要是来自南方的墨西哥湾。此地过去曾经是一个内陆湖,自从内华达山脉的冰河时期消失后,再也没有春日融化的雪水注入湖中,加上炙热的气候,一年之中就足足蒸发150寸的湖水。死亡谷气候之所以如此干燥,另一个主要原因是因为内华达山(Sierra Nevada)、帕那敏山(Panamimt)以及阿加斯山(Agus)三座山形成了雨水屏障,由太平洋吹来的海风所挟带的湿气几乎都没有办法进到谷内,让此地的降雨机率更是微乎其微。
死亡谷虽然被视为地球上最不适于居住的地区之一,但是却生长着一些适应力奇强无比的生物。其中棉球沼泽(Cottonball Marsh)的沙漠小鱼可以住在比海水多出6倍盐分的水中。
Death Valley National Park is a mostly aridarid adj.干旱的, 贫瘠的(土地等), 无趣的, 沉闷的 National Park located east of the Sierra Nevada mountain range in Inyo County, California, USA with a small section extending into Nevada. The park covers 5,219 mi2 (13,518 km2), encompassing Saline Valley, a large part of Panamint Valley, almost all of Death Valley, and parts of several mountain ranges. The Devil,s Hole portionportion n.一部分, 一分 of the park is located in Nevada and is near the Ash Meadows National Wildlife Preserve. It is the hottest and driest of the national parks in the United States and contains the lowest point in the Western Hemisphere at Badwater which is 282 feet (86 m) below sea level. It is also home to many species of plants and animals that have adapted to this harsh desert environment. Some examples include Creosote Bush, Bighorn Sheep, Coyote, and the Death Valley Pupfish - a survivor of much wetter times.
Mining was the primary activity in the area before it was protected. The first known nonNative Americans to enter the Valley did so in the winter of 1849, thinking they would save some time by taking a shortcut to the gold fields of California. They were stuck for weeks and in the process gave the Valley its name even though only one of their group died there. Several shortlived boom towns sprung up during the late 19th century and early 20th to exploitexploit vt.开拓, 开发, 开采, 剥削, 用以自肥 v.使用 minor local bonanzasbonanza n.富矿带, 带来好运之事, 幸运 of gold. The only longterm profitable ore to be mined, however, was borax; a mineral used to make soap and an important industrial compound. 20Mule Teams were famously used to transport this ore out of the Valley, helping to make it famous and the subject or set of numerous books, radio programs, television series and movies. Death Valley National Monument was created in 1933, placing the area under some protection. In 1994, the Monument was promoted to the status of National Park, as well as being substantially expanded.
The natural environment of the area has been profoundly shaped by its geology, which is very long and complex. The oldest rocks are extensively metamorphosed and at least 1700 million years old. Ancient warmshallow seas deposited marine sediments until rifting opened the Pacific Ocean. Additional sedimentationsedimentation n.沉淀, 沉降 occurred until a subduction zone formed off the coast. This uplifted the region out of the sea and created a line of volcanoes. Later the crust started to pull apart, creating the Basin and Range landform we see today. Valleys filled with sediment and, during the wet times of ice ages, with lakes, such as Lake Manly.
Geographic Setting
Within the park there are two major valleys: Death Valley and Panamint Valley - both of which were formed within the last few million years and both bounded by northsouth trending mountain ranges. These and adjacent valleys follow the general trend of Basin and Range topography with one modification: there are parallel strikeslip faults that perpendicularlyperpendicularly adv.垂直地, 直立地 bound the central extent of Death Valley. The result of this shearing action is additional extension in the central part of Death Valley which causes a slight widening and relatively more subsidence there.
Uplift of surrounding mountain ranges and subsidence of the valley floor are both occurring. The uplift on the Black Mountains is so fast that the alluvial fans (fanshaped deposits at the mouth of canyons) there are relatively small and steep compared to the huge alluvial fans coming off of the Panamint Range. In many places socalled “wine glass canyons” are formed along the Black Mountains front as a result. This type of canyon results from the relatively fast uplift on this mountain range doesn,t allow the canyonscanyon n.〈美〉峡谷, 溪谷 enough time to cut a classic Vshape all the way down to the stream bed. Instead a Vshape ends at a slot canyon half way down with a relatively small and steep alluvial fan for the stream sediments to collect on.
The highest range in the park is the Panamint Range with Telescope Peak being its highest point at 11,049 feet (3368 m). Death Valley is a transitional zone in the northernmost part of the Mojave Desert and is five mountain ranges removed from the Pacific Ocean. Three of these are significant barriers; the Sierra Nevada, Argus Range, and the Panamint Range. Air masses tend to lose their moisture as they are forced up over mountain ranges, in what climatologists call a rainshadow effect. The exaggerated rainshadow effect for the Death Valley area makes it North America,s driest spot, receiving about 1.7 inches (43 mm) of rainfall annually at Badwater (some years fail to register any measurable rainfall). Annual average precipitation varies from 1.90 inches (48 mm) overall below sea level to over 15 inches (380 mm) in the higher mountains that surround the Valley. When rain does arrive it often does so in intense storms that cause flash floods which remodelremodel vt.重新塑造, 改造, 改变 the landscape and sometimes create ephemeral very shallow lakes.