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人死后要如何才能变成化石

更新时间:2018-3-7 20:18:49 来源:千亿千亿国际娱乐官网 作者:佚名

How can I become a fossil?
人死后要如何才能变成化石

Every fossil is a small miracle. As author Bill Bryson notes in his book A Short History of Nearly Everything, only an estimated one bone in a billion gets fossilised. By that calculation the entire fossil legacy of the 320-odd million people alive in the US today will equate to approximately 60 bones – or a little over a quarter of a human skeleton.

每一块化石都是一个小小的奇迹。正如比尔·布莱森(Bill Bryson)在他的著作《万物简史》(A Short History of Nearly Everything)中提道,据估计,十亿块骨头只有一块能变成化石。据此计算,如今美国的3.2亿左右的人口仅能留下60多块骨头化石——只比一副人类骨架的四分之一稍多一些。

But that’s just the chance of getting fossilised in the first place. Assuming this handful of bones could be buried anywhere in the US’s 9.8 million sq km (3.8 million square miles), then the chances of anyone finding these bones in the future are almost non-existent.

但是这只是变成化石的概率。如果假定这些骨骼化石分布在美国980万平方公里的任何地方,那么未来寻找到它们的概率几乎为零。

Fossilisation is so unlikely that scientists estimate that less one-tenth of 1% of all the animal species that have ever lived have become fossils. Far fewer of them have been found.

成为化石的可能性太小了,以至于科学家估计在地球上生活过的所有生物只有不到千分之一变成了化石。其中被发掘的更是少之又少。

As humans, we have a couple of things going for us: we have hard skeletons and we’re relatively large. So we’re much more likely to make it than a jellyfish or a worm. There are things, however, you can do to increase your chances of success.

在这方面,人类有几个优势:我们拥有坚硬的骨骼,并且体型相对较大。所以,我们变成化石的机会比水母和虫子的概率大得多,而且你还可以通过一些方法来增加(人骨成为化石)成功的概率。

Taphonomy is the study of burial, decay and preservation – the entire process of what happens after an organism dies and eventually becomes a fossil. To answer the question of how to become a fossil, BBC Future spoke with some of the world’s top taphonomists.

埋藏学(Taphonomy,又称化石形成学)是一门研究埋葬、腐化和防腐的学问——在生物死亡以后,要经历这整个过程才会最终变成化石。为解答生物如何变成化石的问题,BBC Future请教了全世界最重要的几位埋藏学家。

1. Get buried, and quickly

1.尽快入土

“It’s really a question of maintaining a good condition of the body after death – long enough to be buried under sediment and then altered physically and chemically deep underground to become a fossil,” says Sue Beardmore, a taphonomist and collections assistant at the Oxford University Museum of Natural History.

"实际上,问题主要是在死亡以后将尸体保存在良好的条件下——时间要足够长,这样可以埋到沉积物下面,然后在地下深处经历物理和化学变化,最后变成化石,"牛津大学自然史博物馆(Oxford University Museum of Natural History)的埋藏学家、馆藏助理苏·比德莫尔(Sue Beardmore)说。

“To be preserved for millions of years, you must also survive the first hours, days, seasons, decades, centuries, and thousands of years,” adds Susan Kidwell, a professor at the University of Chicago. “That is, you must survive the initial transition from the ‘taphonomically active zone’… to a zone of permanent burial, where your remains are unlikely to be exhumed.”

"想要留存数百万年,就必须坚持数小时、数天、几个季度、几十年、几百年、几千年不腐坏,"芝加哥大学教授苏珊·基德韦尔(Susan Kidwell)补充道,"也就是说,人必须经历从化石活跃区间至长期埋藏区间的最初过渡阶段,在长期埋藏区间,尸体就不太可能被发掘了。"

There are almost endless ways that fossilisation can fail. Many of these happen at, or down to 20-50cm below, the soil or seafloor surface. You don’t want your remains to be eaten and scattered by scavengers, for example, or exposed to the elements for too long. And you don’t want them to be bored into or shifted around by burrowing animals.

形成化石中途失败的原因数不胜数。很多发生在地下20厘米至50厘米、土壤层或者海床表面。例如,遗体不可以被食腐动物吃掉、弄散,也不能长时间经受风吹日晒,还不能被穴居动物挖洞或到处移动。

When it comes to rapid burial, sometimes natural disasters can help – such as floods that dump huge amounts of sediment or volcanic eruptions that smother things in mud and ash. “One theory for the occurrence of dinosaur bone beds is firstly drought conditions, that killed the dinosaurs, followed by floods that moved the sediments to bury them,” Beardmore says.

在快速掩埋这方面,有时候自然灾害会帮上忙——比如洪灾会倾泻大量的沉积物,火山喷发时泥土和灰尘会掩埋生物。"有一个理论认为,恐龙骨床的形成过程是从干旱开始,它导致恐龙死亡。接着,洪灾带来的沉积物把恐龙掩埋起来,"比德莫尔说。

Of course, the fact that human bodies are typically buried six feet under (unless cremated) gives you another leg up here. But that isn’t enough on its own.

当然,人类还有一个优势,就是人的尸体通常埋在地下六英尺(火化除外)。但是,光凭这一点是不够的。

2. Find some water

2. 需要一点水

Obviously the first step is dying, but you can’t die just anywhere. Picking the perfect environment is key. Water is one important thing to consider. If you die in a dry environment, once you’ve been picked over by scavengers, your bones will probably weather away at the surface. Instead, most experts agree you need to get swiftly smothered in sand, mud and sediments – and the best places for that are lakes, floodplains and rivers, or the bottom of the sea.

第一步显然就是死亡,但是死亡的地点是有讲究的。挑选一个完美的环境是关键。水是需要重点考虑的一件事。如果死亡的环境十分干燥,尸体就会被食腐动物发现和破坏,骨骼会在地面慢慢被风化。大多数专家认为,尸体要被沙土和沉淀物快速掩埋——最佳场所是湖泊、漫滩、河流或者海底。

“The palaeoenvironments that we often see the best fossils come out of are lake and river systems,” says Caitlin Syme, a taphonomist at the University of Queensland in Brisbane, Australia. The important thing is the rate at which fresh sediments are burying things. She recommends rivers flowing from mountains which cause erosion and therefore carry a lot of sediment. Another option is a coastal delta or floodplain, where river sediment is rapidly dumped as the water heads out to sea.

"发掘出最好的化石的古环境往往是湖泊和河流系统,"澳大利亚布里斯班昆士兰大学(University of Queensland)的埋藏学家凯特琳·塞姆(Caitlin Syme)说。关键是新沉积物掩埋尸体的速度。她推荐的是从山上过来的河流,因为侵蚀作用会带来很多沉积物。另一个选择是三角洲海岸或漫滩,当河水进入海洋时,沉积物会快速堆积起来。

Ideally, you also want an ‘anoxic’ environment: one very low in oxygen, where animals and microorganisms that would digest and disturb your remains can’t survive.

在理想的情况下,还需要厌氧环境:由于氧气含量非常低,腐化和干扰尸体的动物和微生物无法在此生存。

Kidwell recommends avoiding about 50cm below the seafloor, “the maximum burrowing depth of shrimp, crabs and worms that might irrigate the sediments with oxygenated water”, which would promote decomposition and stir up the body.

基德韦尔建议避开海床以下50厘米左右的地方。她说:"这是虾、蟹和虫子可以挖掘到的最深处,它们可能会把含氧气的水引入沉积物中,"而这可能会促使尸体分解和破碎。

“You want to end up quickly after death in a spot that is relatively low elevation, so that it is a sink for sediment, and preferably with standing water – a pond, lake, estuary or ocean – so that anoxic conditions might develop,” she says.

"在死后,尸体最好位于海拔相对较低的地方,这会成为沉积物的水槽。最好还有积水——比如池塘、湖泊、河口或海洋——这样就有可能形成厌氧环境,"她说。

In rare cases, fossils created in these kind of still, anoxic conditions preserve their soft tissues like skin, feathers and internal organs. Examples include the many exquisite feathered dinosaurs from China or the Bavarian quarries that produced the fossils of the earliest bird, archaeopteryx.

还有一些罕见的情况,在稳定的厌氧环境下,化石还能保留皮肤、羽毛、内脏这样的柔软组织。例如中国出土的很多身披精细羽毛的恐龙,还有巴伐利亚采石场出土的最早的鸟类始祖鸟的化石。

Once your fossil gets below the biologically active surface layer, then it's stable and will continue to be buried more deeply as further sediments accumulate, Kidwell says. “The risk for destruction then shifts to a completely different geological timescale, namely that of tectonism.”

一旦化石进入生物活跃层以下,它就会稳定下来,随着沉积物的堆积,继续埋入更深处。基德韦尔说:"那时,被破坏的风险就要改用完全不同的地质时间尺度,即构造变动的时间。"

The question, then, is how long before the sediments encasing the corpse are turned to more permanent stone… and are lifted by geological activity to a height where erosion can expose the remains.

那时,问题就是包裹尸体的沉积物需要多长时间才能变成比较耐久的石块,然后再过多久以后地质活动会把化石送至有侵蚀作用的地方,把它暴露出来。

3. Skip the coffin

3.不用棺材

Now we come to the thorny technicality of what a fossil actually is – and what kind of fossil you want your body to be.

下面是一个棘手的技术问题:化石究竟是什么——以及你希望自己的身体变成哪种化石。

Very generally, anything up to around 50,000 years old is what’s known as a ‘subfossil’. These are largely still made up of the original tissues of the organism. Extinct Pleistocene megafauna found in caves – such as giant ground sloths in South America, cave bears in Europe, and marsupial lions in Australia – are good examples.

通常来说,五万年左右的是亚化石,它大体上仍然是生物原本组织构成的。比如洞穴里发现的已经灭绝的更新世大型动物,典型的例子有南美洲的大地獭、欧洲的洞熊和澳大利亚的袋狮。

However, if you want your remains to become a fossil that lasts for millions of years, then you really want minerals to seep through your bones and replace them with harder substances. This process, known as ‘permineralisation’, is what typically creates a fully-fledged fossil. It can take millions of years.

不过,如果你希望遗体变成能够留存数百万年的化石,那就需要矿物质渗入骨骼,把它变成较为坚硬的物质。这个过程被称作"完全石化",真正的化石通常要经历这个过程才能完成。它能够存续数百万年。

As a result, you might skip the coffin. Bones permineralise most rapidly when mineral-rich water can flow through them, imbuing them with things like iron and calcium. A coffin might keep the skeleton nicely together, but it would interfere with this process.

所以,你可能要舍弃棺材。当富含矿物质的水流过时,骨骼完全石化的速度最快,让铁和钙质渗透到骨骼中。虽然棺材有可能保持骨骼的完好,但是会影响到这一过程。

There is a way a coffin might work, though. Mike Archer, a palaeontologist at the University of New South Wales, suggests burial in a concrete coffin filled with sand and with hundreds of 5mm holes drilled into the sides. This then needs to be buried deep enough that groundwater can pass through.

不过,棺材也可能行得通。新南威尔士大学(University of New South Wales)的古生物学家迈克·阿切尔(Mike Archer)建议使用水泥棺材,里面装满沙子,侧面钻数百个五毫米口径的洞,然后埋到有地下水流经的深处。

“If you want to be a classic bony fossil, a bit like something from Dinosaur Provincial Park in Canada, then something like a [coarse] river sand would be pretty good,” says Syme. “All the soft tissues would be destroyed and you’d be left with this beautifully articulated skeleton.”

"如果你想要成为经典的骨骼化石,就像加拿大省立恐龙公园(Dinosaur Provincial Park)里的化石一样,那么粗颗粒的河沙就相当不错,"塞姆说,"所有的软组织都会被破坏,最后留下一副漂亮的未脱节的骨骼。"

In terms of the minerals, calcium ions which can precipitate into calcite, a form of calcium carbonate, are especially good. “These can start to cement or cover the body which will protect it in the long run, because given time it will most likely be buried at a greater depth,” Syme says.

在矿物质方面,能够渗入方解石(碳酸钙的一种形式)的钙离子尤其好。"钙离子能够覆盖全身,长期保护它,因为如果时间足够,它被埋到更深处的可能性很大,"塞姆说。

Deliberately seeding your corpse with the appropriate minerals, such as calcite or gypsum, might be a way to accelerate this. Encouraging the growth of tough iron-rich minerals would also be sensible as they withstand weathering well in the long run.

特意用合适的矿物质——比如方解石或石膏——来渗入尸体有可能加速这一过程。还可以促进富含铁质的坚硬矿物质增加,因为它可以抵御长期的风吹日晒。

Silicates, from the sand, are also a nice durable mineral to have incorporated. Archer even suggests getting buried with copper strips and nickel pellets if you fancy fossilised bones and teeth with a nice blue-green colour to them.

沙粒中的硅酸盐也是一种非常耐久的矿物质,可以纳入选择。阿切尔还建议,如果喜欢漂亮的蓝绿色骨骼和牙齿,还可以在埋葬时添加铜条和镍丸。

4. Avoid the edges of tectonic plates

4.避开构造板块的边缘

If you made it through the first few hundred thousand years and minerals begin to replace your bones, congratulations! You’ve successfully become a fossil. As sediments build up on top and you get pushed deeper into Earth’s crust, the heat and pressure will aid the process further.

如果尸体历经了数十万年并且矿物质开始取代骨骼,那么就要恭喜了!它已经成功变成化石。随着上方的沉淀物的增加,它越来越深入地球的地壳。高温高压会进一步促进化石的形成。

But it’s not a done deal yet. Your fossil might still shift to such depths that it could be melted by the Earth’s heat and pressure.

但是还没有结束。化石还有可能进入地壳深处,在高温高压下熔化。

Don’t want that to happen? Steer clear of the edges of tectonic plates, where the crust is going to eventually get sucked under the surface. One such subduction zone is Iran, where the Eurasian Plate is rising over the Iranian Plate.

不想要发生这种事吗?那就避开构造板块的边缘,这些地方的地壳最后可能会被吸到地表以下。伊朗就是这样一个俯冲带,欧亚板块正在升高,把伊朗板块压在下面。

5. Get discovered

5.等待被发现

Now you need to think about the potential for rediscovery.

现在你需要考虑被人发现的可能性。

If you want somebody to chance upon your carefully preserved fossil one day, you need to plan for burial in a spot that currently is low enough to accumulate the necessary sediments for deep burial – but that will eventually be pushed up again. In other words, you need a place with uplift where weathering and erosion will eventually scour off the surface layers, exposing you.

如果你希望有朝一日有人能够碰巧发现你精心保存的化石,你就需要寻找一个目前很低、有足够的沉淀物把你埋到深处的地方——但是最后这个地方要重新被推高。换句话说,你要找到这样一个地方:自然侵蚀会把表层剥离,最后让你重回地面。

One good spot might be the Mediterranean Sea, Syme says; it’s getting shallower as Africa is pushed towards Europe. Other small, inland seas that will fill with sediment are good bets, too.

其中一个好地方可能是地中海,塞姆说。随着非洲向欧洲靠拢,地中海正在变浅。其他富含沉淀物的内陆小型海洋也值得一试。

“Perhaps the Dead Sea,” she says. “The high salt would preserve and pickle you.”

她说:"死海也不错,高盐度会有防腐作用。"

6. Or go rogue

6.另辟蹊径

We’ve covered the standard method for hard, durable fossils with bone largely replaced by rock. But there are some oddball methods to consider, too.

我们已经介绍了变成坚硬、耐久的化石的标准方法,就是用石头替代骨骼。但是还可以考虑一些别出心裁的方法。

Top of the list is amber. There are astounding fossils perfectly preserved in this gemstone made of tree resin – such as recent finds of birds, lizards and even a feathered dinosaur tail in Myanmar. “If you can find a large enough amount of tree sap and get covered in amber, that’s going to be the best way to preserve your soft tissues as well as your bones,” Syme says. “But it’s obviously pretty difficult for such a large animal.”

首先是琥珀。有很多保存完好的化石都是在这种由树脂制成的宝石中——比如最近发现的鸟类、蜥蜴,还有在缅甸发现的有羽毛恐龙的尾巴。"如果能够找到足够数量的树脂,然后让琥珀覆盖全身,那就是同时保存软组织和骨骼的最佳方法,"塞姆说,"但显然,对人这样的大型动物来说,这是很困难的。"

Can’t find enough amber? The next option is tar pits of the kind that have preserved sabre-toothed cats and mammoths at La Brea in Los Angeles. Although here you would mostly likely end up disarticulated, your bones jumbled in with other animals. There’s also freezing on a mountain or in a glacier, like Ötzi the iceman, found in the European Alps in 1991.

找不到足够的琥珀吗?另一个选择是洛杉矶拉布雷亚(La Brea)为剑齿虎和猛犸象完成防腐的沥青坑。不过,最后这里的尸体很可能会脱节,骨骼可能会和其他动物混到一起。还可以在山上或冰川冷冻起来,比如1991年在欧洲阿尔卑斯山发现的冰人奧茨(Ötzi)。

Another route might be natural mummification, with your body left to dry in a cave system. “There are a lot of cave system remains that get covered with calcium from groundwater, which also forms stalactites and stalagmites,” Syme says. “People like caving and so if the cave systems still exist in the future, they might happen upon you.”

另一种途径是自然木乃伊化,也就是把尸体放在洞穴系统中风干。"有很多在洞穴系统中保存的尸体从地下水获得钙质。这种钙质还会形成钟乳石和石笋。"塞姆说,"人们喜欢穴居,所以假如未来还有洞穴系统,那么你可能会用到它。"

One final method to preserve your corpse almost indefinitely, though not in the form of a fossil, would be launching you into space – or leaving you on the surface of a geologically inert celestial body with no atmosphere, such as the Moon.

最后还有一种几乎可以永远保存尸体的方法,不过不是以化石的形式,而是把它发射到太空,或者把它留在没有大气层的地质惰性的天体表面,比如月球。

“The vacuum of space would be very good if you want your body to remain perpetually non-decaying,” Syme says. She adds that you could attach a radio beacon if you want to get found again in the distant future.

"太空的真空环境对尸体的永久防腐非常有利,"塞姆说。她还补充说,如果你希望在遥远的未来能够再次被人发现,你还可以在尸体上安装一个无线电信标系统。

7. Leave a little something extra

7.留下一点额外的东西

Assuming you are found millions of years hence, what else might be preserved alongside you?

假如数百万年后你被人发现,你还想在身旁留下些什么?

Plastics (fidget spinners, anyone?), other oil-derived products that don’t biodegrade and inert metals, like alloys, gold and rare metals of the kind found in mobile phones, all might last as long.

塑料制品(有人想留一些指尖陀螺吗?)等其他不会发生生物降解的石油制品,还有惰性金属,比如合金、黄金和手机里的稀有金属。这些东西都能够保留同样长的时间。

Glass is durable too, and can withstand high temperatures and pressures. You can imagine finding the “outlines or shape of smartphones,” Syme says. Archer notes that the durability of glass means you could chisel ‘ENJOY!’ on a small sheet of glass in a concrete coffin with your body and it would be there to find with your fossil.

玻璃也很耐久,并且可以承受高温高压。你可以想象找到"智能手机的轮廓或形状,"塞姆说。阿切尔提到,玻璃的坚实性意味着你可以在水泥棺的一小块玻璃上凿上"玩得开心!"的字样。当有人找到你的化石时,就能看到它。

“To be 100% sure I would use diamond,” Syme adds – it’s immensely stable. Using a laser, you could etch a letter explaining the lengths you went to to get fossilised.

"为了保证100%成功,我会用金刚石,"塞姆补充说——它非常稳定。你还可以用激光在金刚石上刻下一封信,解释为了变成化石经历的整个过程。

If you also want to pre-plan your archaeological context, Syme believes bitumen highways and the foundations of skyscrapers are contenders. “We’ve dug down deep into the ground to build these things. You’ll be able to see… the layouts of cities still there,” she says.

塞姆认为,如果你还想提前规划自己的考古学环境,那么还可以考虑沥青高速公路和摩天大楼的地基。"在建造这些东西之前,我们挖到了地下深处。在那些地方,城市的布局会一直留存下去。"

Remember, the words you write will fade and your deeds will be forgotten. But a fossil? That, perhaps, could last forever.

记住这件事:你写下的词句会磨灭,你的所作所为也会被人遗忘。但是你的化石呢?它有可能会永远留存下去。

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