科學家在南極發(fā)現(xiàn)了古代雨林的痕跡

科學家在南極發(fā)現(xiàn)了古代雨林的痕跡

Since time immemorial, Earth's poles have resembled frozen wastelands. Life can and does exist there, but there are sound reasons why humans and most other animals cling to the safety of more hospitable climates closer to the equator.

自古以來，地球的兩極就像冰凍的荒地。生命可以而且確實存在于那里，但人類和大多數(shù)其他動物之所以堅持在靠近赤道的更適宜氣候的安全地帶生存，有著充分的理由。

They were not always wastelands, though. We know that in our planet's ancient past, conditions were vastly different. In the mid-Cretaceous Period, about 90 million years ago, dense concentrations of atmospheric CO2 would have created much hotter global temperatures, melting polar ice sheets, and sending sea levels soaring to up to 170 metres (558 feet) higher than they are today.

不過，它們并不總是荒地。我們知道，在我們星球的遠古歷史中，情況大不相同。在大約9000萬年前的白堊紀中期，大氣中高濃度的二氧化碳會造成更高的全球溫度，極地冰原融化，海平面比現(xiàn)在高出170米(558英尺)。

What would the South Pole have looked like in a world like that? Thanks to a stunning scientific discovery, we have our answer.

在那樣的世界里，南極會是什么樣子?多虧了一項驚人的科學發(fā)現(xiàn)，我們有了答案。

In 2017, during an expedition aboard the RV Polarstern in the Amundsen Sea, researchers drilled deep into the ground underneath the seabed of West Antarctica, close to the location of the Pine Island and Thwaites glaciers, and only about 900 kilometres (560 miles) away from the South Pole.

2017年，在阿蒙森海(Amundsen Sea)，研究人員乘坐RV極地號(RV Polarstern)進行考察時，在南極洲西部海床下進行了深入的鉆探，接近松島(Pine Island)和斯維特(Thwaites)冰川的位置，距離南極只有約900公里(560英里)。

約9000萬年前沉積時的南極地區(qū)簡圖

What they pulled up, particularly at depths of around 30 metres, starkly contrasted with the sediment composition resting closer to the surface.

他們打撈上來的東西，特別是在大約30米的深度，與靠近地表的沉積物成分形成鮮明對比。

"During the initial shipboard assessments, the unusual colouration of the sediment layer quickly caught our attention," says geologist Johann Klages from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Germany.

德國亥姆霍茲極地和海洋研究中心阿爾弗雷德·韋格納研究所的地質(zhì)學家約翰·克拉奇說:“在最初的船上評估中，沉積層的不同尋常的顏色很快引起了我們的注意。”

"The first analyses indicated that, at a depth of 27 to 30 metres (88 to 98 ft) below the ocean floor, we had found a layer originally formed on land, not in the ocean."

“最初的分析表明，在海底27至30米(88至98英尺)深處，我們發(fā)現(xiàn)了一層原本是在陸地上形成的，而不是在海洋里。”

They were in uncharted territory, in more ways than one. Nobody had ever pulled a Cretaceous Period sample out of the ground from such a southern point on the globe. Even so, the researchers can't have been prepared for what closer examination with X-ray computed tomography (CT) scans would reveal.

他們在很多方面都處于未知的領(lǐng)域。從來沒有人從地球上這么南的地方從地下挖出白堊紀的樣本。即便如此，研究人員還沒有準備好接受x射線計算機斷層掃描(CT)的進一步檢查。

Back on land, scans described an intricate network of fossilised plant roots. Microscopic analyses also found evidence of pollen and spores, all pointing to the preserved remains of an ancient rainforest that existed in Antarctica approximately 90 million years ago, eons before the landscape was transformed into a barren province of ice.

在陸地上，掃描圖描繪了一個復雜的植物根系化石網(wǎng)絡(luò)。顯微鏡分析還發(fā)現(xiàn)了花粉和孢子的證據(jù)，所有這些都指向大約9000萬年前存在于南極洲的古老雨林的遺跡，那是在南極洲變成一個貧瘠的冰原之前的億萬年。

"The numerous plant remains indicate that the coast of West Antarctica was, back then, a dense temperate, swampy forest, similar to the forests found in New Zealand today," says palaeoecologist Ulrich Salzmann from Northumbria University in the UK.

來自英國諾森比亞大學的古生態(tài)學家Ulrich Salzmann說:“大量的植物遺跡表明，在那時候，南極洲西部海岸是一片濃密的溫帶沼澤森林，類似于今天在新西蘭發(fā)現(xiàn)的森林。”