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      4萬年前人類腳印將美洲人類史提前英語美文

      時間:2024-11-08 08:10:01 英語美文 我要投稿
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      4萬年前人類腳印將美洲人類史提前英語美文

        英國科學(xué)家日前宣布,他們在墨西哥中部發(fā)現(xiàn)的人類腳印已有大約4萬年的歷史,從而推翻了此前有關(guān)美洲出現(xiàn)人類的歷史不會超過1.5萬年的結(jié)論。

      4萬年前人類腳印將美洲人類史提前英語美文

        A group of British scientists claimed yesterday to have identified human footprints in central Mexico that are 40,000 years old, almost three times older than the most generally accepted evidence for human settlement in the Americas.

        據(jù)英國《衛(wèi)報》7月5日報道,由英國利物浦大學(xué)、波恩茅斯大學(xué)和牛津大學(xué)的科學(xué)家組成的科研小組稱,他們在墨西哥發(fā)現(xiàn)的250多個足跡中,有三分之二屬于人類的腳印,其中包括成年人和小孩的腳印。這些腳印是當(dāng)時人們在還未凝固的火山巖上行走時留下的。

        科協(xié)家通過放射性碳鑒定技術(shù)和激光學(xué)鑒定技術(shù)斷定,這些腳印屬于人類,且約有4萬年的歷史。除此之外,科學(xué)家還發(fā)現(xiàn)了一只蝸牛、一只水蝸牛和一顆猛犸的牙齒,并斷定它們也約有4萬的歷史。

        2003年9月,在墨西哥中部一個湖邊被廢棄的采石場中的火山巖上,科學(xué)家發(fā)現(xiàn)了這些人類足跡,但當(dāng)時許多科學(xué)家都堅信人類到達(dá)美洲的歷史不會超過1.5 萬年。在經(jīng)過近兩年的爭論后,這一發(fā)現(xiàn)在近日才正式被公開。其實早在上個世紀(jì)60年代,科學(xué)家就在此地發(fā)現(xiàn)了古代動物的遺骨和早期人類居住地的痕跡,但當(dāng)時的鑒定技術(shù)無法測定出這些發(fā)現(xiàn)物的準(zhǔn)確年代。

        傳統(tǒng)史學(xué)觀點認(rèn)為,大約1.2萬年前的“冰河期”晚期,美洲人祖先從歐亞大陸經(jīng)由“白令海峽”到達(dá)美洲。先前,也有科學(xué)家認(rèn)為,人類來到美洲大陸的時間可能要比這一說法早上數(shù)千年。但是,上述腳印的發(fā)現(xiàn)證明,人類在4萬年前曾居住在墨西哥中部。這推翻了史學(xué)家們長期以來深信不疑的美洲人歷史不會超過1.5 萬年的結(jié)論。

        Group of British scientists claimed yesterday to have identified human footprints in central Mexico that are 40,000 years old, almost three times older than the most generally accepted evidence for human settlement in the Americas.

        The team from universities in Liverpool, Bournemouth, and Oxford are convinced that the footprints are human and represent several adults and children who walked in freshly fallen volcanic ash in the Valsequillo Basin, about 80 miles south-east of Mexico City.

        Working with international colleagues, they have applied dating techniques on the sediment itself and on finds including a land snail, a water snail and a mammoth tooth, all of which came back with an age of around 40,000 years.

        The footprints had to be disentangled from animal tracks, more than 250 marks in all. Casts, which Matthew Bennett of Bournemouth University described as "unmistakably human" were produced from laser modelling at the site, employing a technique used to make industrial prototypes.

        Although the findings were announced after two years of work at the British universities and elsewhere, they are controversial, defying the conviction of many scientists that humans arrived in the Americas not more than 15,000 years ago.

        The tracks were made in gritty ash from the volcano, protected by later sediment layers, and underwater for long periods. The ash layer has since become as hard as concrete, and was locally quarried as a building material, which is how the footprints resurfaced.

        Scientists partially excavated the quarry in the 1960s, and found ancient animal bones and hints of a very early habitation site, but with the technology of the day could not date them accurately.

        The British team revisited the site two years ago. Silvia Gonzalez, from Liverpool John Moores University, first spotted the trail of marks, and described her instant conviction that they were human and very ancient as "like a thunderbolt in my mind".

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