西内SINE

我知道有些人不喜欢胡佛大坝和格伦峡谷大坝阻塞河流来发电或防止洪水。有人说这对动物和鱼类来说是个问题。即使对那些记得过去的人来说，这也是个问题。但这种情况在人们看到之前已经发生过很多次了。我引用书本上的话:
I know some people do not like that the river is blocked by Hoover Dam and Glen Canyon Dam to make power or prevent flooding. Some say this is a problem for animals and fish. It's a problem even for people who remember how it was. But this has happened many times before any people ever saw it. I quote from books:

埃德温·迪·麦基《大峡谷地区的古代景观》，1931年，布鲁斯·巴比特《大峡谷:选集》(弗拉斯塔夫:北国出版社，1978):
Edwin D. McKee, Ancient Landscapes of the Grand Canyon Region, 1931 as in Bruce Babbitt, ed. Grand Canyon: An Anthology (Flagstaff: Northland Press, 1978):

在沙漠景观点(纳瓦霍)下面的岩石和科罗拉多河河边，有明显几处[阿尔冈纪]火山活动形成的黑色悬崖......
Among the rocks below Desert View (Navajo) Point and bordering on the Colorado River [there] may readily be seen several black cliffs formed by the volcanic activity of [the Algonkian Era]...

源自国家公园管理处，2008年12月2日检索和编辑:
NPS Retrieved and edited 12/2/2008:

在过去的两百万年里，大峡谷西部发生了数百次火山喷发。至少有十几次，熔岩从内峡谷的岩壁上倾泻而下，形成了巨大的熔岩坝，阻挡了科罗拉多河的流动。其中三个熔岩坝超过1000英尺高，形成了类似于鲍威尔湖或米德湖水库的湖泊。有些湖泊超过100英里长，多年来一直填满着大峡谷的下部，直到最终超过大坝并侵蚀掉大部分。在托罗韦普地区和熔岩瀑布附近的河流中，可以看到火山渣锥、熔岩流和大坝的遗迹。
In the western Grand Canyon hundreds of volcanic eruptions occurred over the past two million years. At least a dozen times, lava cascaded down the walls of the Inner Gorge, forming massive lava dams that blocked the flow of the Colorado River. Three of these lava dams were over 1,000 feet high, forming lakes similar to reservoirs such as Lake Powell or Lake Mead. Some of the lakes were over 100 miles long and filled the lower portion of the Grand Canyon for many years before finally over-topping the dam and eroding much of it away. Cinder cones and the remnants of lava flows and dams are visible in the Toroweap area and from the river near Lava Falls.

● 获得书籍
● Get book