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
1 The Earth might have been sent into an ice age by the break-up of a supercontinent 750 million years ago, creating a global s
1 The Earth might have been sent into an ice age by the break-up of a supercontinent 750 million years ago, creating a global s
admin
2010-01-18
47
问题
1 The Earth might have been sent into an ice age by the break-up of a supercontinent 750 million years ago, creating a global snowball.
2 The break-up probably caused an increase in rainfall and weathering of rock, say climatologists. This would have sucked greenhouse gases out of the atmosphere and caused a run-away cooling effect. The mechanism could explain how the entire planet becomes encased in a mass of ice, as many researchers think it has done in the past.
3 The theory that the Earth was once completely frozen emerged in the 1960s, when scientists realized that global freezing could happen if the polar ice sheets grew above a certain threshold size. Because bright ice reflects sunlight and heat back into space, growing ice sheets cause further cooling. This feedback loop could tip the climate system into a deep freeze.
4 The planet could eventually thaw as carbon dioxide from volcanoes poking through the ice warm it.
5 In the late 1980s, Joe Kirschvink of the California Institute of Technology nicknamed this state ’Snowball Earth’. Around the same time, geologists began to uncover hints in the geological record that this freeze-thaw process might have happened at least once in the distant past-at the end of the Proterozoic eon, 600 to 800 million years ago.
6 But it was unclear what could have tipped the world into that state in the first place. Now Yannick Donnadieu of the Laboratoire des Sciences du Climat et de L’Environnement in Gif sur
Yvette, France, and co-workers provide an explanation in this week’s Nature.
7 Donnadieu and colleagues have run computer simulations of global climate change 750 million years ago during the break-up of Rodinia, a supercontinent in which nearly all of the present-day continents were welded together around the South Pole. As the vast land mass fragmented into smaller pieces, driven by the engine of continental drift, they found that evaporation from smaller seas between the isolated continents increased the rainfall over land areas.
8 The increased rainfall in turn speeded the weathering of any exposed rock. As rock is worn away by water, chemical reactions take place in which carbon dioxide from the air becomes bound up in carbonate minerals. The more rain there is, the more of this greenhouse gas is extracted from the air.
9 The team also note that the break-up of Rodinia was prompted in part by the eruption of great plains of volcanic rock. The fresh rock from a volcano is more reactive than old rock, and so it weathers more quickly, sucking up even more carbon dioxide.
10 In the researchers’ computer models, the combined effects of higher rainfall and quick-weathering rock reduced the levels of carbon dioxide below the threshold needed to trigger a Snowball Earth.
11 Proving that a Snowball Earth once existed, and understanding how it came about, will help researchers understand more about our planet’s climate and the evolution of life. Some scientists think that the thaw after a deep freeze could have stimulated the appearance of the first multicellular organisms, by providing lots of empty space into which new life could expand. There was indeed a proliferation of such life in the late Proterozoic, though no one can yet prove why.
12 The theory may also help predict whether a Snowball Earth will happen again. But there is no need to panic. Estimates say the planet will not form a new supercontinent for another 250 million years.
The theory about a Snowball Earth is significant in that it can _____________.
选项
A、decode the mystery of life
B、predict the formation of a new supercontinent
C、adjust the planet’s climate
D、prevent another Snowball Earth from happening
答案
B
解析
本题为细节理解题。据第11段最后1句可排除A。C、D都与第9段的内容不符。据最后1段最后1句可确定B。
转载请注明原文地址:https://kaotiyun.com/show/2yvO777K
0
专业英语八级
相关试题推荐
A、Shewasill.B、Shewasafraid.C、Shewasanxious.D、Shewasexcited.C
A、Theeducationcentre.B、Theuniversitybookstore.C、Theuniversitylibrary.D、Thestudentcafeteria.B
WhyMenExplodeAlthoughwomengetangryjustasoftenasmen,rageremainstheprototypicalmaleemotion."Mykidsstillta
A、Givehersomeadviceonhowtostrikeabargain.B、Introducehertothelocalpeople.C、Helpherwiththevolunteerwork.D、Sh
Researchershaveknownthatsecondhandsmokecanbejustasdangerousfornonsmokersassmokingisforsmokers,butnowthere’s
总体上来说,女性工作时间更长,收入更低,工作中的乐趣更少,研究表明,同等工作,男性能挣到一美元,而女性只能挣到74美分。这句话也是一个比较句,做笔记时要把比较的内容记下来。longerhours,lesspay,enjoyment,另外一个是要把第二个
A、Employeescanreceiveperiodicpayincreasesbasedontheirwork.B、Thesalaryforthepositionisabovetheindustryaverage.
ThePanoramaisnotthefirstmodelofNewYork.In1845E.PorterBelden,asavvylocalwhohadwrittenthebestcityguideof
Ingeneral,oursocietyisbecomingoneofgiantenterprisesdirectedbyabureaucraticmanagementinwhichmanbecomesasmall,
TheNCAAmustbefeelingabitlikeDr.Frankensteinthesedays:assailedbycollegefootballandmen’sbasketballplayerswhor
随机试题
CCITT对30/32路PCM。系统的同步系统规定,复帧前方保护时间为()。
A.血管通透性增加B.中性粒细胞趋化作用C.两者均有D.两者均无缓激肽
A.阴虚B.标实本虚C.属实属热D.伏痰遇感引触肺胀的病理性质多属
心脏收缩力增强时,静脉回心血量增加,这主要是因为()(1999年)
生物碱最常用的沉淀反应试剂是
根据《土地管理法》及其他相关自然资源立法的规定,下列说法中正确的是()。
当项目处于规划或项目建议书阶段,又无其他类似工程可以参照时,其投资估算的编制方法一般采用()。
小众经济:指面向小众人群的个性化定制模式,即采用个性化生产加工方式为用户提供独一无二的产品,实现精准服务,以满足消费者需求。下列不属于小众经济的是()。
汉代首先提出“独尊儒术"思想的是()
在大数据技术框架中,不包括__________环节。
最新回复
(
0
)