科学美国人60秒:Sahara Reveals Remains of Ancient River

“The city of Tanis was consumed by the desert in a sandstorm which lasted a whole year. Wiped clean by the wrath of God.” Indiana Jones’s friend Marcus Brody, explaining the fictional fate of the city of Tanis in Raiders of the Lost Ark.

坦尼斯在持续了一整年的沙城暴中，被沙漠所掩埋了，被愤怒的上帝彻底清理干净。一位来自印第安纳州姓琼斯的人，他的朋友马库斯·布罗迪在《夺宝奇兵》中阐述了这座城市小说般的命运。

Back in real life, scientists have found something else covered by the Sahara’s sea of sand: an ancient river system. The remains of the main channel—which dried up long ago—wind beneath the west African desert for more than 300 miles before reaching the Atlantic Ocean.

在现实生活中，科学家们发现了被撒哈拉沙漠所掩埋的其他东西：一条古老的河系。河流已经干涸了很久，其主要通道的残留物蜿蜒在西非沙漠之下300多英里之后到达大西洋。

Researchers led by Charlotte Skoniezcny of the University of Lille in France uncovered the system using a kind of satellite-borne radar that can penetrate through several feet of dry surface sediments like sand. The scientists think that the network may extend even farther inland, but thick dunes prevented them from mapping it. They report their findings in the journal Nature Communications.

法国里尔大学的 Charlotte Skoniezcny领导的研究人员，通过一种可以穿透沙子干燥的表面沉积物的卫星载运雷达，发现了这个古代的河道。科学家认为该河流可能向内陆扩展的还要深一些，但是厚厚的积沙最终阻止了他们用卫星扫描地图。该研究结果发表在《自然通讯》杂志上。

The discovery solves the mystery of what created a vast underwater canyon off the coast of Mauritania in northwest Africa. The subsurface ravine looks like those that form at the mouths of massive rivers today. But researchers had only hypothesized the existence of major waterways in West Africa until now.

该研究结果解决了，在非洲西北部，毛里塔尼亚海岸有一个巨大的地下峡谷之谜。地表下的峡谷就像是今天大量河流交汇处形成的那些峡谷一样。但是研究人员们直到今天之前也还只能认为这种大型水路体系的存在是个假说。

The fact that rivers raged at the surface in this region sheds light on the Sahara’s tumultuous history. Scientists know that this vast desert wasn’t always dry. At certain times in the past, it boasted green grasslands teeming with life. The researchers think the Sahara’s lost river last flowed 6,500 years ago, revealing just how fast west Africa’s climate can change. Maybe not quite as fast as Indiana Jones swapping out a bag of sand for a golden idol. But still, surprisingly fast. “Wiped clean.”

该地区表明曾经流淌的河流揭示了撒哈拉沙漠动荡的历史。科学家们认为这个广袤的沙漠以前并不是干旱的。在古代的某个时期，撒哈拉沙漠生机勃勃，孕育了许多生命。研究人员认为，撒哈拉所流淌的河流大概是在6500年消失，这同时也揭示了西非气候变化之快。也许没有Indiana Jones为黄金神像换出一带沙子那样快。但是，仍然还是很快的。一扫而光。