首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Something very unusual happened about 80,000 years ago, as Earth’s last ice age was getting started. Sea levels that had been dr
Something very unusual happened about 80,000 years ago, as Earth’s last ice age was getting started. Sea levels that had been dr
admin
2013-09-07
34
问题
Something very unusual happened about 80,000 years ago, as Earth’s last ice age was getting started. Sea levels that had been dropping for thousands of years—as more and more water became trapped in expanding glaciers(冰川)—suddenly rose, according to a new study. Then after a few thousand years, the levels fell again. Although the researchers haven’t found the cause of this phenomenon, they say the findings could force at least a partial rethinking of the mechanisms governing Earth’s climate.
For the past several hundred thousand years, our planet seems to have followed a fairly regular climate cycle. About every 100,000 years, kilometers-thick ice sheets form atop the northernmost reaches of North America, Europe, and Asia and extend well into the mid-latitudes. The ice sheets also tie up so much seawater that ocean levels can drop by over 100 meters. Then, after about 90,000 years, the glaciers retreat and land reappears, until the next ice age begins. The last ice age ended about 11,000 years ago.
Various researchers going back nearly a century have attempted to isolate the cause of the ice-age cycle. They have uncovered several factors—periodic changes in Earth’s orbit around the sun, for example —that seem to be in play. But so far no one has presented the definitive answer.
In the recently published Science, a team doesn’t so much solve the puzzle as reinforce the uncertainties about how the ice-age cycle behaves. What they’ve found is very strong evidence that when Earth should have been preparing for the last ice age, the seas rose.
The researchers found that sea level 80,000 years ago had rebounded to the point where it rose 1 meter higher than it is today. And it could have risen quite quickly, as much as 2 meters per century, says geochemist Jeffrey Dorale of the University of Iowa.
That suggests the glaciers were melting at a tremendous rate. Even half that rate would still be "a major finding," Dorale says. So it "has major implications for future concerns with sea-level change."
The study "shows persuasive evidence" for a surge in sea level about 80,000 years ago, says geologist Daniel Muhs of the U.S. Geological Survey in Denver. He says the findings help make a "powerful" argument for the phenomenon. Still mysterious, however, are other data, taken from Barbados and New Guinea, that also suggest rising sea level about 80,000 years ago but not nearly as much of a change. It means, Muhs says, "that there is much about interpreting the geologic(地质学的)record of sea-level variation that we still do not understand."
According to Daniel Muhs, data taken from Barbados and New Guinea suggested that the sea level
选项
A、remained unchanged
B、didn’t rise much
C、rose remarkably fast
D、rose mysteriously
答案
B
解析
倒数第2句中的however和not nearly as much of a change都表明这两个地方的海平面上升的幅度“几乎不能算是变化”,即巴巴多斯和新几内亚获取的数据应显示海平面上升的幅度不大,本题应选B。
转载请注明原文地址:https://kaotiyun.com/show/ov97777K
0
大学英语六级
相关试题推荐
By2030,peopleover65inGermany,theworld’sthird-largesteconomy,willaccountforalmosthalftheadultpopulation,compar
By2030,peopleover65inGermany,theworld’sthird-largesteconomy,willaccountforalmosthalftheadultpopulation,compar
ThewholeworldputattentiontotheSouthAsiawherethetsunamihappened.Before,musiciansproduceda"sonictsunami”,WallS
Therehasbeensomeinterestingworkonthesecondquestion:onattitudestoviolence.Thisfindsadifferencebetweenwesterns
A、Thestudentscanworkcloselywiththefamouswriter.B、ThestudentscanlearnalotfromMs.Irvine.C、TheEnglishDepartment
Thebiographerhastodancebetweentwoshakypositionswithrespecttothesubject(研究对象).Tooclosearelation,andthewriter
Ahostagesituationisfurtherworsenedbythefactthatbystanderscouldbehurtbystraybullets.Toeffectivelypromoterela
Itwouldbeinterestingtodiscoverhowmanyyoungpeoplegotouniversitywithoutanyclearideaofwhattheyaregoingtodoa
Accordingtotherequirements,it’sessentialthat________________(这些申请表格必须尽快交还给公司).
A、Achocolatechipmaker.B、Abigrealestateagent.C、Acookiefactory.D、Atalentagency.D短文一开始说,Amos本来是WilliamMorris公司的一个tal
随机试题
“星法院”颁布特别法令,严厉管制出版活动始于()
A.良性肿瘤B.恶性肿瘤C.潜在恶性肿瘤D.肿瘤样病损E.继发性肿瘤
脂质体的特点为
在计量信用风险的方法中,下列不属于《巴塞尔新资本协议》中标准法缺点的是()。
商业银行债券投资的策略包括分散化投资策略、梯形投资策略和杠铃投资策略。()
各个时代的统一性是如此紧密,古今之间的关系是双向的。对现实的曲解必定源于对历史的无知,而对现实一无所知的人,要了解历史也必定是徒劳无功的。对这段文字理解正确的是()。
纯粹的教育书院出现于()。
A.条件(1)充分,但条件(2)不充分B.条件(2)充分,但条件(1)不充分C.条件(1)和条件(2)单独都不充分,但条件(1)和条件(2)联合起来充分D.条件(1)充分,条件(2)也充分E.条件(1)和条件(2)单独都不充分,条件(1)和条件(2
例如:男:小王,帮我开一下门,好吗?谢谢!女:没问题。您去超市了?买了这么多东西。问:男的想让小王做什么?A开门√B拿东西C去超市买东西
Forlaymenethnologyisthemostinterestingofthebiologicalsciencesfortheveryreasonthatitconcernsanimalsintheirno
最新回复
(
0
)