地球 独一无二的星球 Earth, a unique planet,
瞬息万变 永不休止 restless and dynamic.
大陆板块迁移碰撞 Continents shift and clash,
火山爆发 冰川凝结消融 volcanoes erupt, glaciers grow and recede--
巨大的力量不断作用 titanic forces that are constantly at work,
留下一系列地质谜题 leaving a trail of geological mysteries behind.
当中最神秘莫测的当属死亡谷 And there is nowhere more mysterious than Death Valley,
它是全美最干燥炎热的沙漠 the hottest and driest desert in the United States.
在这里重达三百公斤的岩石 This is a place where even 700-pound rocks
都能自己移动 appear to move by themselves.
这里也是美国的海拔最低点 It's the lowest point in the U.S.,
而这里 and right here,
几乎也是地球上地壳最薄的地方 the Earth's crust is thinner than almost anywhere else on the planet.
对于那些对岩石了如指掌的研究者来说 Death Valley is a dynamic laboratory for investigators
这里则是最生动的实验室 who uniquely read rocks like x-rays
他们可以了解地球内部情况和历史 to reveal the inner workings of the Earth and its history...
进一步解密 adding to the continuing story of "How The Earth Was Made."
地球起源
死亡谷
死亡谷是本土四十八州中最大的国家公园 Death Valley is the largest National Park in the lower 48 states,
面积比罗德岛州大三倍 more than 3 times the size of Rhode Island,
横跨加利福尼亚和内华达 straddling the border of California and Nevada
四周被高山环绕 and surrounded by towering mountain peaks.
225公里长 最宽处达24公里 140 miles long and up to 15 miles wide,
温度可达57摄氏度 with temperatures reaching a scorching 134 degrees Fahrenheit,
注意 极度炎热 危险
这里是地球上最荒凉的地方之一 this is one of the most inhospitable places on Earth.
但对于地质学家来说 死亡谷魅力非凡 But for geologists, Death Valley has a unique attraction.
在这里他们可以 Here they can witness
看到地球上最巨大的地质力量相互作用 the interplay of the Earth's most titanic geological forces.
当你看到死亡谷 When you look at Death Valley,
就好比看到一座战场 really you're looking at a battle,
一场地球表面 a battle between processes
托尼·普拉韦博士 圣安德鲁斯大学地质学家
各种地质作用之间的战争 that are occurring on the Earth's surface,
我们能够看到 and we can see the record of
这些自然的力量被铭刻在岩石中 those forces of nature locked into the rocks.
死亡谷拥有世界上最无与伦比的地质地貌 Death Valley has an archive that is almost unrivaled worldwide.
为了了解死亡谷的早期历史 To uncover Death Valley's earliest history,
普拉韦正在寻找死亡谷最古老的岩石 Prave is hunting for its oldest rocks.
他正在死亡谷最偏僻的地方搜索 He is searching in one of its most remote spots,
在死亡谷的最南端 in the extreme south of the valley
也就是亚历山大峰 in the isolated Alexander hills.
这个就是死亡谷最古老的岩石了 This is one of the oldest rocks in Death Valley.
它已经存在十二亿年了 It's 1.2 billion years old.
根据这块岩石的颜色 And given the color of this rock
以及这种松软的质地 and the fact that it's quite soft--
你看我这样刮它就能刮出粉末来 it can powder when I scratch it--
这些特点告诉我这是块石灰岩 These are all clues that tell me that this is a limestone.
石灰岩是重溯这片干旱的不毛之地 The limestone is a major clue to revealing the way
往日景象的重要线索 this arid desert used to look.
如果我们想一想 If we think about the type of environments
能发现石灰岩的环境 that limestones can be deposited in,
首先想到的就是 the first that comes to mind
有水而且必须为海水 is an underwater and a marine setting.
能形成石灰岩的物质只有一种 There is only one way to form limestone.
那就是海洋生物骨骼和甲壳 It is made from the tiny bones and shells of sea creatures.
当它们死掉后尸体沉积在海床上 They die and sink to the sea floor,
一层层的尸体在重力挤压下 where the weight of further layers on top of them
慢慢地变成坚固的岩石 crushes them slowly into solid rock.
普拉韦还发现了其他能证明 And Prave has discovered other startling evidence
死亡谷从前是汪洋大海的证据 that Death Valley had a watery past.
化石也是主要线索 Fossils are a major clue.
它们是地质学家极为看重的证据 They are vital in the type of evidence that a geologist will use.
而这些在古老岩石上的化石 And these are some very nice examples of the type of fossils
就是你能找到的绝佳例子 that you can find in these ancient rocks.
你可以看到这些弯曲的表面轮廓 And you can see here these curving surfaces outlining
看着像被切成两半的大个卷心菜 what look to be large cabbages that are sliced in half.
这些就是变成层叠石的藻类化石 These were algae known as a stromatolite.
颇具讽刺意味的是 Ironically, these marine fossils
这些海洋化石能在死亡谷幸存 have survived in the Death Valley desert
是因为死亡谷水太少 only because there is so little water
否则它们早就被冲走了 that might otherwise have washed them away.
但十亿年前 But they would have originally looked like this
当它们在死亡谷水域繁衍升息 when they flourished in the Death Valley waters
并形成石灰岩时 看起来是这个样子 as the limestone formed more than one billion years ago.
这些证据告诉我们 These tell us that the environment
岩石形成时 死亡谷是片浅海 when this rock formed would have been a shallow sea.
如果我回到这些岩石刚刚成型的那个时代 If I'd been here when these rocks were first being formed,
那我应该穿着泳裤坐在齐腰深的浅海滩上 I'd be sitting in my swimming trunks about waist-deep in water,
就像今天的巴哈马群岛 very much like the Bahamas today.
这些叠层石是地球上最早孕育生命的地方 The stromatolites are some of the earliest signs of life on our planet.
为了了解在接下来的十亿年中发生了什么 To discover what happened over the next one billion years,
普拉韦开始研究周围山脉中的证据 Prave studies evidence in the surrounding hills.
山体中不同颜色的岩石层 The different bands of colors and the rock layers in the hills
代表了曾经覆盖死亡谷的古代海域 represent ancient seas that covered the Death Valley area.
海水留下一层石灰岩 The seas would deposit a layer of limestone,
退去再回来 move back across the land.
又留下一层石灰岩 Another layer of limestone would be deposited.
因此十多亿年后我们仍能了解 And so we have a history of the seas
海域在死亡谷变迁的历史 moving across the Death Valley region
从层叠石开始形成之日 from the time of the stromatolites to these rock layers now,
至它们变成岩层的今天 more than a billion years later.
地质学家们想要了解 Geologists wanted to figure out
是什么样的地质剧变能让死亡谷 what dramatic geological upheaval could have turned
从一片浅海滩变成如今烈日炎炎的沙漠 Death Valley from a shallow sea to the baking-hot desert of today.
而普拉韦已经 And Prave has found clues in a rock
在和他以前研究的海洋石灰岩 that is entirely different from the marine limestones
截然不同的岩石中找到了线索 he has studied up until now.
这是一块很好的花岗石样品 This is a nice example of a rock type called a granite.
它形成了我身后的山坡上的岩脉 And it forms those veins that are in the hillside behind me.
这些就好比我是手上的手指 You can think of these like the fingers of my hand.
它们向上运动 They're fed upward
来自地下的一片巨大广阔花岗岩区域 from a much more larger, massive area of granite sitting underneath.
这些花岗岩告诉科学家们 The granite tells scientists
为什么死亡谷的海洋会消失殆尽 the reasons why Death Valley's ancient seas vanished.
现在它们是冰冷的岩石 Today, it is solid rock.
但它们从前可是地底炽热的岩浆 But it was once hot molten magma from deep underground.
只有一种自然力量能有如此大的力量 Only one force of nature has the awesome power
以及1100摄氏度的高温 and 2,000-degree Fahrenheit heat
能把岩石融成岩浆并带到地表 to melt rock into magma and fire it to the surface...
那就是火山 Volcanoes.
这里的海洋并不是自己干涸的 The seas here didn't just drain away.
它们是被这些火焰山逼退的 They were pushed back by these mountains of fire.
直到上世纪六十年代 It was only in the 1960s,
人们才了解到 with the realization that
地球上的大陆是板块漂移的结果 Earth's continents were drifting around the planet,
这样一来科学家才了解到 that scientists figured out
为什么死亡谷下会有火山出现 why the volcanoes erupted under Death Valley.
板块构造学揭示出 The theory of plate tectonics revealed that
大约一亿年前 around 100 million years ago,
一块古老的海洋板块沉入北美板块下面 an ancient oceanic plate began sinking under North America,
抬高了陆地 pushing up the land.
冲击的热量形成了海岸火山带 Heat from the collision powered a coastal chain of volcanoes,
并在地表喷发 erupting on the land
并且最终把浸没死亡谷的海洋逼退 and finally driving away the seas submerging Death Valley.
当时火山喷发时常发生 This landscape would have been very explosive,
地理条件恶劣 a hostile type of setting.
奠定了今天死亡谷的环境基调 And that then set the stage for what was to become Death Valley.
时至今日仍在死亡谷存在的幽灵小镇 Still surviving in the valley to this day is the ghost-town,
是一种远比花岗岩稀有的物质存在的证据 evidence of another substance far rarer than granite
它们也由火山带到地表 that the volcanoes grought to the surface...
金子 Gold.
尽管全美有三十多个州发现了金矿 Although gold occurs naturally in more than 30 different U.S. States,
但当死亡谷的岩浆在地表附近凝固时 the gold in Death Valley was concentrated in veins in the rock,
金子就集中在岩石的岩脉中 as magma solidified near the surface.
这让开采变得十分容易 It made it worth mining,
在形成数百万年后 and millions of years after its formation,
死亡谷迎来了淘金热 it sparked the Death Valley gold rush.
这里是一处很好的金矿矿井 This is a wonderful example of a gold mine shaft.
也就是帕纳明特山顶上的尤里卡矿井 It's the Eureka mine, high up in the Panamint Mountains,
矿井是为了在花岗岩中寻找 associated with trying to find gold in the granites
一两亿年前嵌进石头的金子 that were intruded into these rocks 100 to 200 million years ago.
金子本在岩脉中 The gold would have been in veins,
它们在这些岩石中穿行 these fingers that would have been injected up into these rocks.
金矿就在这些岩脉中集中 And the gold would have been concentrated in these veins.
这里的淘金热只持续了几年 The gold rush here lasted just a few years.
淘金者们必须得清走一吨的岩石 Miners often had to remove a ton of rock
才能发现不到三克的金子 to recover only 1/10th of an ounce of gold,
也就是刚刚能够打造出一枚婚戒 enough to produce just a single wedding ring.
今天只剩下空空如也的矿道和无人的小镇 Today, all that remains are empty tunnels and ghost towns.
这么想来很有趣 It's interesting to consider that
当年的淘金热 the frenzy of activity, mining gold,
其实是由1亿到2亿年前的火山活动 was actually a direct result of the kind of volcanic activity
而直接导致的 100 to 200 million years ago.
地质学家们正在研究当年在死亡谷肆虐的 Geologists investigating the battle that raged in Death Valley
古代海洋和狂暴火山之间的战争 between fiery volcanoes and ancient seas
他们发现了重要的证据 have found important evidence.
层叠石
叠层石化石能证明 Stromatolite fossils are proof
死亡谷曾经处于一片浅海之下 that Death Valley was once submerged by the waters of a shallow sea.
花岗岩
花岗岩中的岩脉 Veins of granite could only
只有在火山的高热中才能形成 have formed in the fiery heat of the volcanoes
1亿年前火山自地下喷发而出 that burst to the surface around 100 million years ago
把海洋逼退 and drove that sea away.
火山塑造着这片土地 The volcanoes built up the land
也就是之后的死亡谷 that was to become Death Valley
喀斯喀特山脉 位于北美洲 最高峰海拔4392米
当时其山峰能与喀斯喀特山脉比肩 into peaks as high as the Cascades Mountain Range.
但在地表之下的深处 But deep beneath the Earth's surface,
巨大的地质力量正在摧毁这些山峰 awesome geological forces were about to destroy those peaks,
撕裂这片土地 stretch the land apart,
改造了死亡谷的山脉 and transform the mountains of Death Valley
使它变成了美国海拔最低的地方 into the lowest point in the U.S.
10亿年间 For a billion years,
死亡谷都是海底的一片平原 Death Valley remained a flat plain under the sea.
大约1亿年前 Around 100 million years ago,
喷发的火山形成了高耸的山脉 erupting volcanoes formed high mountain ranges.
然而此后真正地质谜题的出现了 But then the real geological mystery began.
这片土地肯定经过了沧桑巨变 The land here must have undergone an extraordinary transformation.
因为今天的死亡谷中 because today in Death Valley,
高耸的山脉已经消失了 those high mountain ranges have vanished.
难以置信的是 曾经的山脉 Incredibly, the one-time mountains
现在沉降到了海平面以下 have sunk below sea level
变成了北美洲海拔的最低点 to become the lowest point in North America.
而且在死亡谷周围 Yet all around the valley,
白雪皑皑的山峰仍然高耸入云 snow-capped peaks still soar up to
高达3300米 11,000 feet into the air.
我们的研究深入地底 The investigation digs deep under the landscape
想要找到是怎样的地质力量 to discover what vast geological forces
才能令仅仅相距30公里的两个地方 could have caused that huge difference in height between two places
在高度上有巨大差异 just 20 miles away from each other.
死亡谷有着很多谜团 There are a lot of mysterious aspects about Death Valley.
这里的景观很奇特 It's a unique landscape,
因为谷底本身非常低 because the valley floor itself is very deep.
玛丽·米勒博士 地质学家 俄勒冈州大学
低于海平面 It's below sea level.
但两边的山脉却巍然耸立 And the mountains rise up very steeply on either side.
这种地下力量的线索 Clues to the power of these
其实在谷中随处可见 underground forces lie all over the valley...
只要你知道怎么找 If you know where to look.
最初一层一层的岩石 Many of the rock layers
沉积在古代平坦的海床上 were originally deposited on the ancient flat sea bed.
现在还能看到它们水平的岩层 they can still be seen as horizontal layers.
但附近其他的岩层就完全不是水平的 But other nearby layers aren't horizontal at all.
他们倾斜向下进入地底 They tilt downwards into the ground.
米勒在一个非同寻常的火山渣锥中 Miller finds a further clue of Earth's power
发现了地球力量的进一步的线索 in the unusual shape of this cinder cone,
死亡谷谷底的火山灰和火山碎石堆 A mound of ash and debris lying on Death Valley's floor.
这看上去像是两个火山渣锥 It looks like it's two cinder cones,
但实际上它们原本是一个 but in fact it's really just one
只是被断裂层分开成了两个 that's been pulled apart along a big fault zone.
它在70万年间移动了200多米 This has moved some 700 feet in some 700,000 years.
大约一千年移动0.3米 So that's about a foot per thousand years,
乍听上去好像很慢 which sounds like it's really, really slow,
但和地质时间的长度相比较的话 but if you look at it over a great length of geologic time,
你会大吃一惊的 you get quite a lot of slip.
如果时间更久 断层的水平错距会更长 And give it even longer time, it will be offset even more.
米勒的下一个挑战 Miller's next challenge
是找出到底是什么导致了断层线的移动 is explaining what is making the fault line move.
为此 她研究了其他古代岩石的形态 For that, she studies other ancient rock formations
它们参差不齐的外形使其得名为龟背地形 whose jagged outline has given them the name turtlebacks.
龟背地形对于 The turtlebacks are crucial
理解死亡谷的起源非常重要 to understanding Death Valley's early origins.
它们记录着这里的地质变化 They have so much of the record here,
如果你愿意花时间解开这个谜题 If you're willing to spend time to try to unravel it.
真正的线索就在岩石与众不同的纹理中 The real clue lies in the rocks' distinctive texture.
仔细地观察下这块岩石 If you just take a look at this rock closely,
它看上去很脆弱 很纤细 you can see that it's very kind of strung out, very stringy.
它的纹理是细颗粒组成的 It tends to be pretty fine grained.
这样的纹理告诉了米勒它的来源 This texture tells Miller where these rocks came from.
证据表明这些岩石是经过变形的 We see evidence that these rocks were deformed,
就好比你把一块塑料加热之后 just like if you'd take a piece of plastic and were to heat it up,
你就能把它扳弯 you could bend it.
岩石也是一样的 It's the same thing with rock.
这些岩石是在地下约30公里处的地壳中 And so these rocks formed at high temperatures and pressures
在高温高压下发生变形的 within the Earth's crust at depths of about 10 miles or so,
然后才被地质运动带到地表 and they have since been brought to the Earth's surface.
米勒总结出一定是某种巨大的地下力量 Miller concluded that some overwhelming underground force
把龟背地形的岩石带上了地表 must have raised the turtleback rocks to the surface
像拉扯热太妃糖一样形成了死亡谷 and stretched them out like warm toffee as Death Valley formed.
这里的地质运动的最终答案 The final explanation of what happened here once again
是全球的大陆板块漂移 came back to the way continents drift around the globe.
板块的碰撞 As the collision of the plates
使得古代火山升上地表 that had forced ancient volcanoes to the surface
但碰撞的力量逐渐减弱消失 slowed down and ceased,
曾经占据地表的高山 The high mountains that once dominated the land
慢慢地被撕开 并倒下 were slowly pulled apart and tilted downwards.
下方的地壳逐渐变得越来越薄 Gradually, as the underlying crust grew thinner and thinner,
在山脉之间形成了深深的盆地 a deep basin formed between the mountain ranges.
死亡谷是这种地壳张力的 Death Valley is the most extreme example
最极端例子 of what such stretching forces can do.
通过检测地震波 By measuring seismic waves,
科学家们发现 scientists discovered that here
这里的大陆地壳只有约25公里厚 the continental crust is just 16 miles thick.
听上去好像很厚 This might sound like a lot,
但这比地球上其他任何地方的地壳都要薄 but it is far thinner than almost anywhere else on the planet.
全球范围来看 Around the globe,
大陆地壳平均厚度约为40公里 the Earth's continental crust averages 25 miles thick.
最厚的在喜马拉雅山脉下 It's strongest beneath the Himalayas.
有近70公里 At 43 miles,
这样的厚度才能承受其上众多山脉的重量 thick enough to support the weight of massive mountains
例如珠穆朗玛峰 such as Everest.
龟背地形也让米勒找到了 The turtleback rocks also offer Miller evidence
死亡谷的地壳拉伸是何时开始的证据 as to when Death Valley's stretching started.
对这些岩石的年代测定显示 Dating these rocks reveals that
尽管地壳变形是从1300万年前开始 the deformation started here around 13 million years ago,
但死亡谷的成形不是一蹴而就的 although Death Valley did not take on its final shape immediately.
死亡谷 Death Valley's really young
从地质年代上看来还非常年轻 when you look at the whole geologic time scale.
现代的死亡谷 Modern Death Valley is
其年龄最多只有三到四百万年 probably 3 or 4 million years old at the most.
地壳是在那之前开始拉伸 The stretching started before that.
但死亡谷本身是最近才形成的 But Death Valley itself is a very recent feature.
科学家们明白拉伸过程还远没有结束 Scientists know that the process is far from finished.
他们在死亡谷以奇异而著名的恶水盆地中 They've found irrefutable evidence in the alien Death Valley landscape
找到了无可辩驳的证据 known as Badwater Basin.
恶水盆地
我现在就处于恶水盆地 I'm standing here at Badwater,
这里是西半球的海拔最低点 which is the lowest point in the western hemisphere.
托尼·普拉维博士 地质学家 圣安德鲁斯大学
海平面
位于海平面以下86米 It's 282 feet below sea level.
我们所站的地方 We're actually standing
距海平面有一个橄榄球场那么深 below sea level about the depth of a football field.
海平面
这里的地面还一直在下沉 This floor has been sinking.
每年下沉3毫米 It's about a tenth of an inch per year,
大约是你手指甲生长速度的一半 which is about half of the speed at which your fingernail grows.
地壳持续不断地被拉伸着 Continual stretching of the Earth's crust
使得恶水盆地成为 has turned Badwater into one of the lowest spots
地球上任何大陆的海拔最低点之一 on any continent on the planet.
然而这里实际的深度还要更低 Yet its true depth is even lower still.
我们在这里看到的只是现在的地表 The surface that we see here is the present-day surface.
但你要明白的是在我们的脚下 But what one has to realize is that beneath our feet,
在此之下 we can go down through sediment
是漫长岁月而产生的沉积层 that represents ancient periods of time,
当时死亡谷的地表比现在还要深约5公里 when Death Valley was a surface that goes down 3 miles.
在这里钻井下去 You would need to drill down through the sediment
钻过11座帝国大厦那么深的沉积层 to a depth equivalent to 11 Empire State buildings end to end
才能到达地壳岩床 before you hit the crustal bedrock.
这盆地上的沉积物总量 The total volume of material in this basin
足以把纽约市埋到1.6公里的地下 would bury New York to the depth of nearly a mile.
周围山脉滚落下碎石 The valley floor is constantly being covered with sediment
不断在谷底沉积 cascading from the surrounding mountains,
但它却永远不会被填满 but it can never fill up completely.
沉积物的沉积速度 The sediment is coming in at a rate
比死亡谷本身沉降的速度要慢 that is less than the rate of sinking of Death Valley itself.
因此峡谷底部的地表始终保持在 So that we're always maintaining a surface here on the valley
海平面之下 that is sitting below sea level
而且还在不断下沉 and is continuing to sink through time.
连续不断的运动 This constant movement shows
体现了地质运动永不休止的的力量 Earth's geological forces at their most dynamic
同时也使死亡谷独一无二 and makes Death Valley unique.
这里最吸引人的就是在任何地区 The allure is that nowhere on Earth do we see continental crusts
都看不到地壳以如此的速度和规模被撕开 being pulled apart at this rate or this magnitude.
对死亡谷形成过程的勘察 The investigation into Death Valley's creation has established
揭示了这里是如何成为北美洲最低点 how it sank to become the lowest point in North America.
龟背地形
板块构造的强大力量 The turtleback rocks were deformed
使得龟背岩变形 by the powerful tectonic forces
致使山脉彼此分离 pulling the mountains apart
从而形成宽阔的谷底 to form a wide valley floor.
恶水盆地
恶水盆地仍旧在不断下沉 The still-sinking landscape of Badwater,
目前低于海平面86米 currently 282 feet below sea level,
证明了峡谷地壳如今仍在不断被拉伸 is proof that the crust here is still being stretched today.
然而地表下沉只是死亡谷的神奇之一 But the sinking of Death Valley is just one part of the story.
地质学家仍然需要探索 Geologists still need to investigate
世界上最为炎热的地区 how one of the hottest places on Earth
是怎样在冰川运动的作用下改变的 was shaped by the power of moving ice.
12亿年前 1.2 billion years ago,
死亡谷曾经是一片汪洋大海 Death Valley was submerged by ancient seas.
大约10亿年之后 Around a billion years later,
随着火山的崛起 海水随之消退 volcanic mountains drove the seas away.
1300万年前 13 million years ago,
大陆地壳开始拉伸分离 the continental crust started stretching apart here.
最终在300万年前 And by 3 million years ago,
死亡谷成为地球上的最低点之一 Death Valley was one of the lowest points on Earth.
地质学家在这里发现的 The clue that showed investigators what happened next
一种鲜为人知却极具研究价值的白色结晶岩 was the discovery in the valley of a little-known but highly valued
揭示了死亡谷之后的演化过程 white crystalline rock.
当人们想到死亡谷地区的淘金者 When one thinks of prospectors in the Death Valley region,
往往会认为他们寻找的是金矿和银矿 one often thinks of them hunting for gold and for silver.
但这里还有另外一种矿石 But there was one mineral
托尼·普拉维博士 地质学家 圣安德鲁斯大学
远没有那么光鲜夺目 那么引人神往 that was much less glamorous, much less sexy and exciting,
这就是硼砂 and that was borax,
然而这种矿石却堪称沙漠中的白金 but it was actually known as the white gold of the desert.
1880年硼砂是稀有但需求量大的矿物 In 1880, borax was a rare but in-demand mineral
广泛用于防腐剂和洗涤剂中 used in antiseptics and detergents.
一对贫穷潦倒的夫妇 One impoverished couple
在死亡谷矿区艰难为生 desperately trying to make a living in Death Valley
他们就是亚伦和罗茜·温特斯 was Aaron and Rosie Winters.
他们从一位过路的淘金者那里得知 They heard from a passing prospector that
开采硼砂能够带来丰厚的收益 they could make good money from borax if they could find it.
他们还从同行的淘金者那里 They learned from their fellow prospector
学会了当时鲜为人知的硼砂勘探手段 the then-secret method of testing rock for borax.
渴望独享矿石带来的利益 Anxious to keep potential profits for themselves,
这对夫妇悄悄等到午夜降临 the couple waited until the dead of night
才开始在死亡谷实验这种方法 to perform the test in Death Valley.
通过灼烧矿石来探测 You burn the mineral to see if
我们这里的粉末状物质中是否蕴含硼砂 the powder that we have in front of us here contains any borax.
温特斯夫妇的方法是 Now, what the Winters did
首先向硼砂矿石中 is to add sulfuric acid
加入硫酸 to borax-bearing mineral.
我们这里加入少许酒精 We'll add some alcohol.
1880年他们用的可能是便宜的威士忌 The Winters probably used cheap whiskey back in 1880.
如果矿石中蕴含硼砂 那么燃烧时 And the flame should burn hopefully a green color
火焰应该呈绿色 if borax is there.
我们可以看到 火焰的确是绿色的 And as we can see, the flame is green in color.
而在1880年 温特斯夫妇意识到 And in 1880, the Winters knew
他们找到了硼砂 终于发财了 that they would become wealthy because they had borax.
从一个微不足道的实验开始 From these humble beginnings,
一项产业在死亡谷应运而生 a whole industry grew in Death Valley.
不仅为温特斯夫妇带来了财富 It made the Winters' fortune
也为科学家们理解死亡谷的地质演变史 and also gave scientists a priceless clue in their quest
提供了十分宝贵的证据 to understand the geological history of Death Valley,
由于像这样的硼砂矿石 Because borax deposits like these
只能在远古淡水湖底岩层中才能找到 can only be found in the beds of ancient freshwater lakes.
而原先覆盖着死亡谷的海水 The sea water that once covered this valley had long gone
早在10亿年前就已经消失了 a billion or more years earlier.
因此硼砂的出现证明 But the presence of borax proves
20万年前的冰河时期 that freshwater must have flooded into the area
当峡谷四周山脉上的冰川开始融化时 when ice-age glaciers started to melt from the surrounding mountains
淡水曾一度淹没死亡谷 around 200,000 years ago.
伴随冰川的融化 As the glaciers melted,
河水便随之注入地表的最低点 死亡谷 rivers flowed towards the lowest point--Death Valley.
从而逐渐在被淹没的峡谷底部 Gradually a vast lake spread out
形成一片巨大的湖泊 across the flooded valley floor.
峡谷的流域面积极大 The valley's catchment area was huge.
河水来自超过2.3万平方公里的区域 Its rivers drained more than 9,000 square miles,
超过了新罕布什尔洲的面积 an area bigger than New Hampshire.
淡水从四周的山脉上顺流而下 The water pouring in from the surrounding mountains leached minerals
溶解出岩石中的硼砂等矿物质 such as borax from the rocks
使其在湖底岩层中沉淀下来 and deposited them on the lake bed.
在大量的湖底岩层中 In a lot of the lake beds,
硼砂这种矿物 this mineral, borax,
看上去就像是一种白色的絮状矿物 would appear as kind of a white fuzzy mineral.
因此也被人称作棉球岩 It was actually called cotton ball.
硼砂证明这里曾经存在过湖泊 The borax proved that a lake existed here.
地质学家将其称作曼利湖 Geologists called it Lake Manley,
以纪念开拓者威廉·L·曼利 after one of the pioneers, William L. Manley,
他在1849年将这里命名为"死亡谷" who had named Death Valley in 1849.
但是科学家无法知晓曼利湖的深度及面积 But they had no evidence to tell them its depth and its size.
最终他们在这座小山上找到了答案 A solution to this puzzle is revealed in this small hill
在峡谷边缘一处名叫比蒂隘口的地方 with a road cut straight through it near the valley's edge
一条公路横穿过这座小山的中央 at a spot called Beatty Junction.
有条路恰好穿过这座岩砾石山 It's very fortunate to have a road cut
对于我们来说十分幸运 right through this gravel deposit.
可以从裸露的岩石上看见圆形的鹅卵石 So, in the exposure, we can see very well rounded pebbles.
还可以观察到石头中天然的岩层 We can also see some crude layering in the gravels.
约翰·卡斯基博士 地质学家 旧金山州立大学
这些石头互相堆积在一起 And they're stacked in against each other.
我们称这种现象为叠瓦作用 And we call that shingling.
岩石的形态及其平滑的表面 The shape and the smoothness of the stones
告诉卡斯基这些碎石是怎样出现在这里的 tells Caskey exactly how these pebbles got here.
石头堆积的方式 The way they're stacked tells us that
向我们展示了在河水的作用下 the direction of water flow
这些碎石形成了现在的形态 that laid these pebbles down like this
水的流向是从右至左的 was from the right to the left.
因此这里一定存在波浪效应 So we know that this had to be wave action.
这充分证明这里过去曾是一片河滩 That's strong evidence that this is a beach environment.
通过观察石滩与谷底的高度差 By looking at the height of this pebble beach above the valley floor,
卡斯基计算着这片湖泊的面积 Caskey calculates the dimensions of the lake.
从我现在所在的这片石滩带 From this beach gravel bar that we're standing on,
湖水泛着波浪拍打在我的脚下 the waves would have been crashing at our feet,
从这里向南 and as we look south,
难以想象出 it's hard to imagine
那边巨大的盐田以前曾是一座湖泊 a lake sitting out there across that vast salt pan.
但曼利湖的面积大约有155平方公里 But Lake Manley would have covered about 600 square miles
深度大约有137米 and it would have been about 450 feet deep.
在死亡谷炎热的天气中 It's odd mapping shorelines
很难想象出湖泊的形态 on a really hot day in Death Valley.
不禁让人十分怀念 You kind of long for the ancient days of yore,
湖泊成群的远古时期 when there were big lakes out here.
过去这里一定是个风景优美的地方 You can imagine this was a beautiful place
四处都是茂密的植被 full of lush vegetation.
与如今这里的景象截然不同 You know, it was quite a different place than it is today.
对于卡斯基来说 接下来需要探索 For Caskey, the next step is discovering why
为什么死亡谷的湖泊消失了 Death Valley no longer has a lake.
死亡谷最为独特的地区 And there is evidence about that
为回答这个问题提供了证据 in one of its most unusual landscapes--
这片崎岖 布满锯齿状白色岩峰的地区 this twisted, jagged field of white peaks
被人称作"魔鬼的高尔夫球场" that's called The Devil's Golf Course.
魔鬼的高尔夫球场
就连这里的声音都十分奇特 Even the sounds here are mysterious.
在寂静的沙漠中 In the silence of the desert,
当无情的烈日吸干了 there is a faint popping noise
干涸地表中的每一寸水分 as the relentless sun sucks every drop of moisture
便可以听到一种微弱的爆裂声 out of the parched surface.
这里的盐层是古代湖泊的遗留物 The salt that we see here is the remains of an ancient lake.
这里被称为"魔鬼的高尔夫球场" It's called Devil's Golf Course
是因为这里恐怕是最不适合 because it's probably the least likely surface
打高尔夫球的地方了 that you would ever want to play golf on.
粗糙的结晶盐覆盖着地表 The surface is made up of rough salt crystals,
在炙热的高温下膨胀收缩 发出声音 popping when they expand and contract in the searing heat,
但这里的盐并非来自海洋 but this salt did not come from the sea.
如同硼砂一样 Just like the borax,
20万年前淡水漫入死亡谷 the salt was leached from the rocks
岩石中的盐分也在流水的作用下 when freshwater started flowing into Death Valley
被溶解了出来 200,000 years ago.
起初盐分被溶解在曼利湖的淡水中 The salt was originally dissolved in the freshwater Lake Manley,
而卡斯基将通过一个简单的实验 and Caskey has a simple experiment to show exactly
来揭示盐分是怎样沉积在谷底上的 how it ended up on the floor of Death Valley.
我将盐水倒在这个容器中 I'll pour the water and salt solution into this pan,
随着水分的蒸发 and as the water evaporates,
我们会看到盐析出 we should see salt forming.
而那正是盐结皮的形成过程 And that's exactly how this salt crust forms.
那么 So...
今天的温度足够高 it's hot enough out here today.
蒸发应该会非常快 It should evaporate pretty quickly.
5分钟后
在很短的时间里 In a fairly short amount of time,
沿着边缘形成了美丽的盐结晶 there are some beautiful salt crystals formed along the edges.
10分钟后
这是盐田形成的基本过程 That's essentially how a salt pan forms.
雨水灌入后 When the rainwater comes in,
盐逐渐溶解 the salt goes into solution,
跟这个水杯里的水差不多 basically just like the water that we have in this water bottle,
而当水开始蒸发时 and from the moment the water starts evaporating,
盐结晶也开始形成 salt crystals start forming.
如今 死亡谷的的盐田 Today, Death Valley's salt pans
面积超过512平方公里 cover more than 200 square miles,
是华盛顿面积的3倍 an area 3 times the size of Washington, D.C.
气候转暖 They are the remnants of the ancient lake
古老湖泊于2000年前最终消失 that finally disappeared 2,000 years ago,
而它们残留了下来 when Earth's climate began to warm up.
从那时起 From then onwards,
死亡谷的气温连年上升 Death Valley's temperatures just kept on rising.
注意 极度炎热 危险
死亡谷绝对是世上最热的地区之一 Death Valley is definitely one of the hottest spots in the world.
根据1913年7月10日记载 The record high was 134 degrees Fahrenheit,
查利·卡拉汉 死亡谷国家公园 管理者
历史最高温为56.7摄氏度 recorded back in July 10, 1913.
给你个直观的概念吧 And just to give you perspective on that,
炉溪地牧场的看管人 the caretaker of the Furnace Creek Ranch,
当天记录下最高温的那个人 who actually was the one doing the recordings back then,
他形容那天炽热难忍 he describes that day as being so hot,
他看见飞翔中的燕子坠地死亡 he saw the swallows falling dead in flight.
如今地质学家清楚是这里特殊的地理条件 Geologists today understand how Death Valley's unusual geology
形成了使湖泊消失殆尽的 is responsible for the punishing climate
恶劣气候 that killed off its lake.
气候极端干燥 It stays so dry
因为湿气从320公里以外的太平洋吹来 because there are 3 distinct mountain ranges between Death Valley
要经过3条不同的山脉 and the moisture carried off of the Pacific Ocean,
才能到达死亡谷 over 200 miles away.
从这往西即是内华达山脉 We have the Sierra Nevadas to the west of us.
风暴满载着水气从西而来 The storms come in from the west laden with moisture.
气流上升时 As they rise up,
会在山的西侧失去大量水 they lose most of that moisture on the west side,
而每经过一座山 and each set of mountains
云团中的水气会减少更多 wicks a little more moisture out of the clouds.
经过了海洋和死亡谷之间的 And here, with our 3 sets of mountains
3道山脉形成的雨水屏障 in between us and the ocean,
水气抵达死亡谷时 by the time that moisture gets to Death Valley,
或者消失殆尽 或者只形成很少量的雨 there's either all gone, or we just get a few drops of rain.
几乎所有来自海岸的暴风雨 Almost all storms from the coast are stopped
都受到这三座山脉的阻挡 by the 3 mountain ranges,
而每一座山的影响 each one in turn having an effect
科学家称之为 雨影效应 the scientists call a rain shadow.
因此我们处于三重雨影效应影响的地区 So we are in the rain shadow of a rain shadow of a rain shadow
年平均降雨量低于50毫米 and average less than two inches a year.
地理环境通过另外一种途径 And there is another way that geology
塑造了这里的沙漠气候 influences the desert climate.
晴空下被加热的空气 Air heated under the cloudless sky
被周围群山阻隔 is trapped by the surrounding mountains.
夏季来临 死亡谷成为致命危险的熔炉 In summer, Death Valley becomes a deadly, dangerous furnace.
当地气象站提供了一项生动的试验 The local weather station provides a graphic demonstration of
演示了高温摧毁死亡谷湖泊的速度 how quickly that heat could have destroyed death Valley's lake.
每天 卡拉汉会检查蒸发速度 Every day, Callagan checks the rate of evaporation.
在夏季 The summer months,
大概需要五桶这个容器的水 it may take 5 of these containers here.
所以我要装满它 倒进水池里 So I'm going to fill them up and dump them into the pond
直到水面高度与针持平 until it brings the water level up to the needle.
目前 这的年均降雨量勉强有50毫米 Now, our average rainfall is barely 2 inches a year,
但蒸发池记录的蒸发量高达3800毫米 but the evaporation pond records up to 150 inches of evaporation.
降雨量和蒸发速度之间 That huge discrepancy between the amount of
相差悬殊 rainfall and the speed of evaporation
这意味着3.7米深48公里长的湖泊 means that a lake 12 feet deep and 30 miles long
仅一年就会因蒸发而干涸 would evaporate in just a single year.
曼利湖的面积更大 Lake Manley was bigger than that,
但时间流逝 它也消失于无形 but over time, it never stood a chance.
科学家对死亡谷的研究 The scientists' studies of Death Valley
揭开了其淡水历史的神秘面纱 have solved the mysteries of its freshwater past.
硼砂
硼砂 发现于19世纪80年代 Borax, discovered here in the 1880s,
证明死亡谷过去被淡水湖填满 proves that Death Valley was once filled with a freshwater lake.
古代河岸上的鹅卵石 Pebbles unearthed on an ancient shoreline
鹅卵石
显示湖泊一度覆盖了1536平方公里 show the lake once covered 600 square miles,
是芝加哥面积的3倍之多 an area 3 times the size of Chicago.
2000年前 最后一片淡水水域枯竭 When the last freshwater pools dried up here 2,000 years ago,
死亡谷成为了美国最干燥的地区 Death Valley started its reign as the driest place in the U.S.,
这令研究的下个阶段具有讽刺意味 which makes it ironic that the investigation's next phase,
科学家正调查死亡谷最近一次的地质巨变 examining the valley's most recent geological upheavals,
研究湍急河水的 involves scientists studying the awesome power
惊人力量 of fast-flowing water.
大约1亿年前 Around 100 million years ago,
死亡谷的古代海洋被喷发的火山取代 Death Valley's ancient seas gave way to exploding volcanoes
随后山峰被撕开 whose peaks were then wrenched apart
变成了美洲的最低处 to create the lowest spot in America.
大约20万年前之前 From around 200,000 years ago,
谷内被淡水湖填满 the valley filled with a freshwater lake.
但四周群山的雨影效应最终又使水干涸了 But the rain shadow of surrounding mountains dried up the water.
过去的2000年间 For the past 2,000 years,
死亡谷成为北美洲 Death Valley has been hotter and drier
最热 最干燥的地方 than anywhere else in North America...
这使探寻马赛克峡谷更加神秘莫测 which makes it all the more mysterious to find Mosaic Canyon,
这条横亘在贫瘠土地上的 a deep chasm seemingly cut by water,
似乎由水流切成的幽深裂谷 in this parched and arid land,
马赛克峡谷
特别是 有证据显示 especially when there is evidence of
巨石像鹅卵石般任凭摆布 massive boulders having been pushed around like pebbles.
看看这块巨石的个头 Just look at the size of that boulder
看看比我脚要高多少 and look at how high above my feet it is.
直径大约有50厘米 It's about 3 feet in diameter,
罗茜·温特斯博士 地质学家 圣荷西州立大学
我甚至无法估计出它的重量 and I can't even estimate what the weight of that thing is.
梅西纳身处荒漠 She may be in a desert,
但她知道 只有一种力量 but Messina knows there is only one force
能将巨石举到如此之高 that could have lifted the boulder up so high.
水将巨石载到这里 并留在了这里 Water brought it here and left it here.
流经此处的水流 The force of the water that came through here
力量必定十分惊人 had to have been pretty severe
才能使巨石嵌进在那么高的岩壁上 in order to get that boulder up there plastered against the wall.
巨石证明 山洪暴发时 This boulder gives us evidence about the force of the water
冲进峡谷的水流威力巨大 that comes down these canyons during flash floods.
山洪是大自然最致命的武器之一 A flash flood is one of nature's most lethal weapons.
如果峡谷现在有山洪倾泻而进 If there were a flash flood coming down this canyon,
我都没有时间从这条路跑出去 I wouldn't have enough time to run out of its path
因为洪流的速度非常快 because the water flows down at an incredible velocity.
山洪是地球上最巨破坏力的自然现象 Flash floods are among the most violent processes on the Earth.
它可以带走SUV车大小的物体 They can carry material the size of an S.U.V.
不费吹灰之力 without any problem at all.
在世界上最干燥的地区之一 In one of the driest places in the world,
洪水有着令人惊讶的来源 the floodwater comes from a surprising source--
雨 rain.
死亡谷的年均降水量仅有50毫米 On average, Death Valley receives just two inches of rain a year.
这个水量尚且不足 This is less than half the rain
纽约的单月降雨量的一半 that falls on New York in a single month.
然而夏季的强烈暴风雨 But violent summer storms
意味着一天就能下完整年的雨量 mean it can all fall in just a single day.
洪水通过不同方式改变着沙漠地貌 The floods transform the desert landscape in a number of ways.
其中一种称为荒漠花开 One is known as the desert bloom,
突发而至的一场雨 where seeds and plants
唤醒了蛰伏10年的植物和花种 that may have lain dormant for up to 10 years
倏地一下 满谷花开 burst into flower after a sudden rainfall.
这样的场景美不胜收 This phenomenon might be beautiful,
但这些洪水 还有凶险的一面 but there is another, deadlier side to these floods,
夺人性命 with a human cost.
前方洪灾
2004年 一场山洪席卷了炉溪地 In 2004, there was a flash flood that came down Furnace Creek.
暴雨灾害 道路封闭
泥浆非常浓稠 It was just this muddy slurry that was dense enough
能够托起一辆车并把它冲下去 to pick up a vehicle and carry it downhill,
一些人不幸因此罹难 and several people died in it.
相比而言 The 2004 flash flood is small
2004年的山洪还比不上 in comparison to some of the events
在这些岩石里留下痕迹的洪水规模 that we see preserved here in the rocks.
山洪在世界各地均有发生 Flash floods happen all over the world,
但证据显示 在死亡谷 but there's evidence here
洪水留下了特殊 罕见的地质影响 of their particular and rare geological effect in Death Valley.
这块大理石非常光滑 This marble is very highly polished.
没有被刮擦 It's not scratched.
没有被打凿 It's not gouged.
是被随着山洪冲刷下来 It's been polished by very fine grained material
颗粒很细的物质打磨而成 that comes down as part of a flash flood.
因此它很光滑并且有沟槽 So it's really smooth, and it's fluted.
这真的很特别 It's really unique.
为了揭开这些特殊光滑岩壁的形成 To uncover how these unusual polished walls were formed,
梅西纳近距离观察地质学家所说的死地 Messina takes a closer look at what geologists term the Badlands.
我想它被称为死是因为这里寸草不生 I think it's called bad because nothing will grow on it.
这里的土质非常松散 There's just this very loose material out here,
很容易被侵蚀以至于植物不能扎根 and it erodes so readily that plants can't even take root.
所以这里是死地 So this is "Bad land."
组成死地的岩石 The rock that makes up the Badlands
是两千年前荡漾在死亡谷的湖泊 is the dried-up remains of the 2,000-year-old lake bed
干涸后留在湖底的沉积物 that once submerged Death Valley.
现在除了干涸的泥土什么也没有了 This is nothing more than desiccated mud.
这叫泥石 因为它有轻微的岩化 It's called mudstone because it's slightly lithified,
意味着它正在变成岩石 meaning it's turned into rock.
泥岩的矿物质成平板状并紧密的堆叠 The mudstone's minerals are arranged in tightly packed, flat sheets.
雨水不能穿透泥岩 The rain can't penetrate the mudstone,
因此 雨水携带大量泥沙 and therefore,the rain picks up a lot of the particles
并把它们运到山下 and carries them downhill.
这些泥沙是 These particles are the key
峡谷岩壁被打磨平滑的关键因素 to the canyon's smooth, polished walls.
它满载着泥沙流过这里 It flows through here so laden with sediment
导致了大量的摩擦和刮刻 that it causes a lot of polishing and incision.
因此每次山洪经过 So every time a flash flood comes through,
峡谷变得更深 岩壁变得更高 this canyon gets deeper, the walls get higher,
岩石表面变得更光滑 and the rock gets more polished.
满载泥沙的洪水 The sediment-laden floods
以惊人的速度和力度冲刷着死亡谷的岩石 can carve into Death valley's rocks with tremendous speed and force.
由于死亡谷一直被拉伸 These canyons have been gouged out
在岩石的脆弱断裂处 where the rocks here have been fractured and weakened
这些峡谷就被洪水切割出来 by the continuous stretching the valley is undergoing.
这是直接的显而易见的地质变化 This is up-front, in-your-face geology happening right here.
死亡谷是动态变化的 Death Valley is dynamic.
人类一生就可以看到这里沧海桑田 This is a place where things are happening in a human lifespan.
在这片干旱的沙漠 In this arid desert,
调查证实水作为最近的因素 The investigation has identified water as the latest factor
影响着死亡谷持续的地质演变 in Death Valley's continuing geological evolution.
巨砾
巨大的石头附着在峡谷壁上 The giant boulders plastered high on the canyon walls
说明沙漠中山洪暴发的力量 illustrate the power of flash flooding in the desert.
光滑的岩壁
马赛克峡谷的光滑岩壁 The smooth walls of Mosaic canyon
显示出远古湖泊的干涸泥岩 show how the dried mud from an ancient lake
至今仍在塑造死亡谷的形态 still affects how Death Valley is being shaped to this day.
然而还有一些谜题没有解开 And yet some mysteries remain unsolved,
包括世界最有趣的地质谜题之一 including one of the world's most intriguing geological riddles
看似可以自己行走的岩石 --the rocks that seem to walk by themselves,
在死亡谷谷底移动数百米 moving thousands of feet across the floor of Death Valley.
12亿年前 Over 1.2 billion years,
死亡谷 Death Valley has been transformed
从大海变为干涸的沙漠 from a watery landscape to a barren desert.
即使地质学家现在知道 But even though geologists now understand the processes
形成这一非凡地区的过程 that have shaped this extraordinary region,
但是这里仍有未解之谜 there are still mysteries to be solved.
死亡谷之内 And there is no part of Death Valley
没有比马场地更神秘的区域 more mysterious than an area known as the Racetrack.
马场地
这片焦热干裂的湖泊盆地 This parched, cracked lake basin
只有4千米长 just 2.5 miles long
1.6千米宽 and a mile wide
却是死亡谷最吸引人的地质谜题 is the setting for one of Death Valley's
所在的位置 most intriguing geological puzzles--
滑行的石头 its sliding stones.
我爱这个地方是因为它的奇特 I love this place because it's odd.
宝拉·梅西纳博士 地质学家 圣荷西州立大学
我可以来这里一百多次 I could come here a hundred more times,
每次这里都会有一些不同 and every time there will be something different,
看见我没见过的一些事情 something I didn't see.
那些岩石后的地面上 Stretching behind these rocks
伸展出长长的槽形轨迹 are long grooved trails in the earth.
很显然它们是岩石 It is clear that they are tracks left behind
在谷底移动留下的轨迹 as the rocks move across the valley floor.
问题是解开岩石 The puzzle is to work out how the rocks can
如何在略微倾斜的地表向坡上滑行的 slide uphill against this slightly tilted surface.
那些不仅仅是小石头 These are no mere pebbles.
有些岩石重达0.3吨 Some of these rocks are over 700 pounds.
有些轨迹接近九百米长 And some of the trails are nearly 3,000 feet long.
在一百年以前 The phenomenon was first recorded here
这一现象最早被科学家记录 by scientists some 100 years ago,
然而 在这偏僻的地方 and yet, in this remote location,
从没有人见过岩石移动 no one has ever seen the rocks moving.
梅西纳从1996年就开始追踪 Messina has been tracking the movement of each individual rock
马场地每一块岩石的移动轨迹 on the Racetrack since 1996.
她GPS的度数可以精确到2.5厘米内 Her GPS readings are accurate to within a single inch.
地质学只不过是侦探工作 Geology is really nothing more than detective work.
比起寻找很久之前 And rather than looking for evidence of things
发生事情的证据 that took place a long time ago,
我很喜欢在马场地工作是因为 what I really like about working on the Racetrack
你寻找的东西都是正在发生的 is you are looking at things that are happening right now.
这是一个进行中的过程 It's an ongoing process.
她的第一线索来自岩石滑动的地表 Her first clue is the surface on which the rocks slide.
如果我把手放在上面 If I try to move my hand over it,
我就可以磨我的指甲了 I could probably file my nails right now.
然而 下雨之后 However, after it rains,
这里众多的湖床淤泥会变得很滑 there's so much clay in the lake-bed sediments that it gets slick.
特氟龙：杜邦公司系列氟聚合物产品 不粘锅内涂层
那有点像特氟龙 It's almost like Teflon.
你不需要很多力量 You wouldn't need very much force
就能移动非常巨大的岩石 to set even a very large rock into motion,
就因为表面的摩擦几乎为零 just because the friction on the surface is almost nil.
但是只有水还不足以移动岩石 But water alone isn't enough to make these rocks move.
梅西纳指出了第二个作用的因素 Messina has identified a second factor at work.
可能有了雨水 You can have rain,
但是如果之后的几天没有风的话 but if you don't have wind a couple of days later,
我想那些岩石也去不了哪里 I don't think these rocks are going anywhere.
马场地是天然的风道 The Racetrack is a natural wind tunnel.
风道从南方直通到山谷 The wind funnels into the valley from the south.
接近地表的风 Close to the ground,
可以超过飓风的强度 the winds can exceed hurricane strength,
时速可达145公里 reaching speeds of over 90 miles per hour,
足够推动岩石移动 enough to push the rocks into action.
如果有风且没有摩擦 If you have wind and there is no friction,
你所要做的 all you'd need to do
就是用手指像这样弹一下 is hit a rock with your finger like that,
然后它就动了 and it would go into motion.
当所有这些因素都满足 When all these elements are in place,
岩石就会开始它们的神奇之旅 the rocks can begin their mysterious journey.
由于从来没人看见过岩石移动 Since no one has ever seen the rocks in motion,
我们只能猜测它们的速度 we can only guess how fast they go.
不过基于我曾见过一些迹象 But based on some of the evidence that I've seen,
无论如何这些岩石不是缓慢移动的 these rocks aren't inching along, by any means.
推测大约5至6公里每小时 And the best estimate we have is about 3 to 4 miles an hour.
优美灵活的移动 So a nice, brisk walk.
不过除非这一想象被目睹 But until this phenomenon is witnessed,
死亡谷滑行石仍旧是个谜 the mystery of Death Valley's sliding rocks will remain.
我希望这个谜题不要被解开 I hope that this mystery isn't solved.
这使我着迷 It's what keeps me interested,
我想很多人都会为此着迷 and I think it's what keeps a lot of people interested.
地质学家调查死亡谷得出 Geologists studying Death Valley have figured out
它特有的地质演变 its extraordinary geological evolution.
叠层石化石显示出 Stromatolite fossils show that
叠层石
这一地区曾被海洋覆盖 this area was once covered by seas.
龟背地形证明 Turtleback rocks prove that
龟背地形
大地曾被板块构造力拉伸 the land was stretched apart by tectonic forces,
使谷底下沉至美洲最低点 dropping the valley floor down to the lowest point in America.
比蒂隘口的鹅卵石证明 Pebbles at Beatty Junction prove that
鹅卵石
死亡谷曾被淡水湖覆盖 Death Valley was once covered with a freshwater lake.
马赛克峡谷被打磨光滑的岩壁显示 And the smooth, polished walls of Mosaic Canyon show that
光滑的岩壁
水现在仍是死亡谷演变的核心因素 water is still at the heart of Death Valley's modern evolution.
死亡谷仍是 Death Valley remains
地球上最极端的地质景观之一 one of the most extreme geological wonders on Earth,
并且它仍在演变 and it's still evolving.
它的谷底仍不断被 Its valley floor is being constantly
来自地球深处的力量拉伸 pushed apart by forces deep within the Earth.
这意味着这里的地壳将持续伸展变薄 This means that the crust here will continue to stretch and thin.
未来千万年之内的某一天 One day, tens of millions of years into the future,
死亡谷将被海水分开 Death Valley could be separated by the sea
远离美国的其它地区 from the rest of the U.S.
今天的死亡谷持续下沉 Today, Death Valley continues to sink
速度稳定在3毫米每年 at a steady rate of 1/10th of an inch a year,
随着它的表面不断被水冲刷 while its surface continues to be sculpted by water,
生动的证明了 地球从未停止改变 living proof that the Earth is never at rest.