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
2016-08-29
19
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."
What happened when the glaciers were melting at a tremendous rate?
选项
A、The mid-latitudes were flooded first.
B、The climate lost its regular balance.
C、The ice age almost came to an end.
D、The sea level rose rather quickly.
答案
D
解析
第6段第1句开头的that指的是第5段提到的海平面以很快的速度上升这个事实,这两句话表明海平面上升和冰川融化有联系,因此,本题应选D。
转载请注明原文地址:https://kaotiyun.com/show/JZG7777K
0
大学英语六级
相关试题推荐
A、Languagespeopleuseininternationalcommunication.B、ThepopularityofEnglishasaworldlanguage.C、ThedevelopmentofEng
A、Englishisthesoleofficiallanguage.B、FewpeoplespeakZuluthere.C、IthasthelargestIndianpopulationoutsideofAmeric
A、Theywillmakevisitorswalkfaster.B、Theywillmakevisitorscovermorearea.C、Theywillmakevisitorsappreciatetheexhib
A、Theywillmakevisitorswalkslower.B、Theywillmakevisitorsstayintheroomforalongertime.C、Theywillstimulatemore
TheTajMahalistoopenonmoonlitevenings20yearsaftersecurityfearsendsnightvisits.India’sSupremeCourtwillallowt
A、Hewasnotinterestedinpoliticalreform.B、Hehadanunusualmilitarycareer.C、Hehadnopoliticalexperience.D、Heexpress
A、Internationaltrade.B、Theincreaseofagriculturalexports.C、Measureofgovernmenttowardfarming.D、Makingmoney.D美国青年农民首要
A、Dailyactivitiesandknowledgearelearnedindifferentways.B、Physicalexperiencesarehelpfulforpeopletolearn.C、People
Parentswhoconsidertheirkidstobe"morespecialthanotherchildren"andfeelthatthey"deservesomethingextrainlife"m
随机试题
在Excel2010中,某区域由A4、A5、A6和B4、B5、B6组成,下列不能表示该区域的是()。
单核细胞病理性增多见于()
泰嘉贸易公司从国外购进100吨钢材,委托某船运公司运往中国境内。一日,该船运公司一艘夹载着该船船员私自在国外购买的500多件电器等物的船,在中国海口市担杆岛附近海域进行走私交易时,被中国某海关抓获。该海关作出决定,将包括该贸易公司100吨钢材在内的船上所有
下列属项属于保证机械失效安全所采取的措施的是()
预制构件的吊环,必须采用未经冷拉的()级钢筋制作,严禁以其他钢筋代换。
如果注册会计师在审计过程中,无法对会计报表整体发表审计意见时,应当出具否定意见的报告。()
下列各项中,反映和描述房地产市场状况的指标有()。
Doanimalshaveaculture?Whatdowemeanby"culture"?Latelysocialscientistshavebeguntoaskifcultureisfoundjustin
请使用VC6或使用【答题】菜单打开考生文件夹proj3下的工程proj3,其中包含了类IntegerSet和主函数main的定义。一个IntegerSet对象就是一个整数的集合,其中包含0个或多个无重复的整数;为了便于进行集合操作,这些整数按升序存放在成员
Arbitrarinessoflanguagewasfirstdiscussedby
最新回复
(
0
)