Early toolmakers were 'engineers' 远古时期的工具制造者是“能
文章来源:未知 文章作者:meng 发布时间:2009-08-14 06:06 字体: [ ]  进入论坛

Early modern humans in South Africa were using "heat treatment" to improve their stone tools about 72,000 years ago, according to new research.


The heat treatment makes the stones more <a href=brittle1" width="226" border="0" src="/upimg/090814/4_063038_1.jpg" />
The heat treatment makes the stones more brittle

This technique may bridge a gap between the use of fire to cook food 800,000 years ago and the production of ceramics2(制陶术) 10,000 years ago.

Evidence for this innovation was found at Pinnacle3 Point, a Middle Stone Age site on the South African coast.

The researchers have published details in the journal Science.

"We found that as early as 165,000 years ago, but definitely 72,000 years ago, people are doing more than just using fires for cooking, heat, light or protection," lead researcher Kyle Brown, from Arizona State University, US, told BBC News.

"I think heating stones is the dawn of human engineering.

"One of the things that makes us uniquely human is that we can take the things in our landscape and adapt them. We can engineer them to fit our needs."

Evidence suggests that about 800,000 years ago, people were able to control fire to cook their food.

By about 10,000 years ago, humans were using fire to make ceramics and to extract iron and copper4 from their ores.

Until now, there was nothing to link these two different uses of fire, the researchers explained.

"These early modern humans seem to have been able to make a big mental jump," Kyle Brown commented.

Cutting edge

The heat treatment makes the stones more brittle(易碎的), making it easier to chop off(砍掉) clean flakes5(鳞片). This produces a fine cutting edge - like a modern day razor blade(刀片) - good for cutting animal skins or making clothing.

However, the breakable edge is not very strong, making it unsuitable for use as a chopping(切) tool in wood working, digging or stone shaping.

The stone tools found at the Pinnacle Point site were made of silcrete(硅质壳层), a hard and resistant6 material that looks like another mineral called quartzite(石英岩) - but is not as coarse(粗糙的).

When the archaeologists searched a 50km radius7 around the site, they could not find the right type of stone required to recreate the ancient tools.

The stones had a different colour and texture8; they were a deeper red, with a high gloss9(高度光泽) and were more brittle.

Mr Brown explained: "What we had spent six years looking for had always been right under our noses.

"Taking that step of putting the stone in the fire and pulling it out… I could imagine what the first people must have thought when they did that and realised that what they just did was going to change their lives."

Mr Brown, who is an experimental archaeologist, tried to recreate the "heat treatment technology" for himself.

Planning ahead

"The fire requires a significant amount of fuel, which you need to gather in advance, together with the stones," he explained.

"Then you bury the stone in sand two centimetres below the fire, and, gradually, over 12 hours, build up the fire. You keep it at about 300 degrees for roughly five hours. Then you gradually let it cool down on its own so the stone does not crack.

"This can take 10 or even 20 hours. So you need to schedule your time, knowing that you need to be around the fire for 40 hours."

Establishing this sequence is crucial(关键的,决定性的), Kyle Brown explained.

"As you can imagine, there are several ways in which materials can be unintentionally burnt on an archaeological site."

At around the same time as the tools were being fired in South Africa, humans had begun harvesting shellfish, making pigments10(颜料) and grinding ochre(赭石).

"These are highly sophisticated people who spread from Africa to eventually colonise the rest of the world," Mr Brown explained.

Heat treatment technology appears to have been known about 165,000 years ago, but it was not used routinely until about 70,000 years ago. It is unclear why the technology suddenly took off.

"Perhaps," the archaeologist speculated, "heat treatment could have become popular because good silcrete stones were scarce. Or it could have been a way to produce high quality material to be traded for other goods".


1 brittle IWizN     
  • The pond was covered in a brittle layer of ice.池塘覆盖了一层易碎的冰。
  • She gave a brittle laugh.她冷淡地笑了笑。
2 ceramics 0a6d841bb40f677207869b9f856b3b21     
  • an exhibition of ceramics by Picasso 毕加索陶瓷作品展
  • The ceramics bore the imprint of Luca della Robbia. 陶器上印有卢卡·德拉·罗比亚的字样。
3 pinnacle A2Mzb     
  • Now he is at the very pinnacle of his career.现在他正值事业中的顶峰时期。
  • It represents the pinnacle of intellectual capability.它代表了智能的顶峰。
4 copper HZXyU     
  • The students are asked to prove the purity of copper.要求学生们检验铜的纯度。
  • Copper is a good medium for the conduction of heat and electricity.铜是热和电的良导体。
5 flakes d80cf306deb4a89b84c9efdce8809c78     
小薄片( flake的名词复数 ); (尤指)碎片; 雪花; 古怪的人
  • It's snowing in great flakes. 天下着鹅毛大雪。
  • It is snowing in great flakes. 正值大雪纷飞。
6 resistant 7Wvxh     
  • Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
  • They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。
7 radius LTKxp     
  • He has visited every shop within a radius of two miles.周围两英里以内的店铺他都去过。
  • We are measuring the radius of the circle.我们正在测量圆的半径。
8 texture kpmwQ     
  • We could feel the smooth texture of silk.我们能感觉出丝绸的光滑质地。
  • Her skin has a fine texture.她的皮肤细腻。
9 gloss gloss     
  • John tried in vain to gloss over his faults.约翰极力想掩饰自己的缺点,但是没有用。
  • She rubbed up the silver plates to a high gloss.她把银盘擦得很亮。
10 pigments 90c719a2ef7a786d9af119297e63a36f     
n.(粉状)颜料( pigment的名词复数 );天然色素
  • The Romans used natural pigments on their fabrics and walls. 古罗马人在织物和墙壁上使用天然颜料。 来自辞典例句
  • The original white lead pigments have oxidized and turned black. 最初的白色铅质颜料氧化后变成了黑色。 来自辞典例句
TAG标签: human tool engineer