有關這一個題目 - 英檢

The Arctic wasn't always covered in ice. Samples of sediment layers beneath a

frozen lake show this region used to be a lot warmer—and may thaw out again

in the future. The work is in the journal Science. [Julie Brigham-Grette et

al., Pliocene Warmth, Polar Amplification, and Stepped Pleistocene Cooling

Recorded in NE Arctic Russia]


El'gygytgyn, a Russian lake 100 kilometers north of the Arctic Circle,

contains layers of sediment that date back to the lake's formation 3.6

million years ago. Analyses of sediment cores have revealed that back then

summers reached about 15 to 16 degrees Celsius, a good 8 degrees warmer than

modern Arctic summers. These warm temperatures, which supported plants like

Douglas fir and hemlock, lasted until about 2.2 million years ago.


Using a sediment core as a detailed history of climate change, scientists can

see how the forested Arctic gradually became covered in ice and snow. These

changes help us understand details about the development of Ice Ages. In

addition, the sediment comes from a window of time during the Pliocene Epoch,

when greenhouse gas levels were only slightly higher than they are today.

Such sensitivity to small carbon dioxide changes hint at a warm Arctic future.

題目是:

Which era did the sediment which revealed the temparature of the summers back

during the formation of the El'gygytgyn belong to?


請英文強的大大幫忙解一下感謝>__<





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