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
Blasts from the Past 1.Volcanoes were destructive in ancient history. Not because they were bigger, but because the carbon di
Blasts from the Past 1.Volcanoes were destructive in ancient history. Not because they were bigger, but because the carbon di
admin
2010-01-13
28
问题
Blasts from the Past
1.Volcanoes were destructive in ancient history. Not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease.
2.Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large number of animals, but all the mass extinction cover the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do.
3.Wignall calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava that they produced. He found that size for size, older eruptions were at least 10 times as effective at wiping out life as their more recent rivals.
4.The Permian extinction, for example, which happened 250 million years ago, is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe. Those volcanoes are thought to have pumped out about 10 gigatonnes of carbon as carbon dioxide. The global warming that followed wiped out 80 per cent of all marine genera at the time, and it took 5 million years for the planet to recover.
5.Yet 60 million years ago in the late Palaeocene there was another huge amount of volcanic activity and global warming but no mass extinction. Some animals did disappear but things returned to normal within ten thousands of years. "The most recent ones hardly have an effect at all," Wignall says. He ignored the extinction which wiped out the dinosaurs at the end of the Cretaceous, 265 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid.
6.Wignall thinks that older volcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO2. Ocean chemistry may also have played a role. As the supercontinents broke up and exposed more coastline there may have been more weathering of silica rocks. This would have encouraged the growth of phytoplankton in the oceans, increasing the amount of CO2absorbed from the atmosphere.
7.Vincent Courtillot, director of the Paris Geophysical Institute in France, says that Wignall’s idea is provocative. But he says it is incredibly hard to do these sorts of calculations. He points out that the killing power of volcanic eruptions depends on how long they lasted. And it is impossible to tell whether the huge blasts lasted for thousands or millions of years.
8.Courtillot also adds that it is difficult to estimate how much lava prehistoric volcanoes produced, and that lava volume may not necessarily correspond to carbon dioxide or sulphur dioxide emissions.
A.than more recent ones
B.the killing efficiency for older eruptions
C.has remained controversial
D.Wignall’s calculations as acceptable
E.has been known to us all
F.his ideas
选项
答案
A
解析
more recent ones较后来的火山爆发。填入后生成的句子不仅在语法上是正确的并且跟文章第一句话的意思差不多。
转载请注明原文地址:https://kaotiyun.com/show/dRGd777K
本试题收录于:
职称英语综合类基础题库职称英语分类
0
职称英语综合类基础
职称英语
相关试题推荐
TheRoleofPressureGroupsinBritainGeneralElectionsinBritainareusuallyheldonlyonceeveryfiveyears.Governmentsca
Accordingtothepassage,whichofthefollowinghaschangedthemostinthelast500years?Whichcountryisthelargestcoffe
TreesTreesareusefultomaninthreeveryimportantways:theyprovidehimwithwoodandotherproducts;theygivehimshade;
TheTelevisionCameraThetelevisioncameraisratherlikethehumaneye.Boththeeyeandthecamerahavealens,andboth
LivewithComputerAftertoolongonthenet,evenaphonecallcanbeashock.Myboyfriend’sLiverpudlian(利物浦的)accentsu
A.fallasleepagain.B.becomemoreenergeticthefollowingdayC.sleeplessthan7hoursD.confirmthoseseriousconsequence
Graphene’sSuperstrengthBigtechnologycomesintinypackages.Newcellphonesandpersonalcomputersgetsmallereveryyear
TheAnimalsinDesertSomedesertanimalscansurvivetheverystrongsummerheatanddrynessbecausetheyhaveveryunusual
ScienceandTruth"FINAGLE"(欺骗)isnotawordthatmostpeopleassociatewithscience,Onereasonisthattheimageofthes
SpellingandWritingThereisapopularbeliefamongparentsthatschoolsarenolongerinterestedinspelling.NoschoolI
随机试题
下列通信介质中,传输速率最高、传输距离最远的是________。
下列哪些不属于彩色多普勒技术
抗原呈递细胞不包括
下列哪一选项属于传闻证据?(2015年卷二26题)
所谓消费主义,简要描述就是,要把超过基本需求的欲望满足作为消费动机,视为人生的根本目的和体现人生价值的核心尺度,以消费更多的社会商品和占有更多的社会财富作为人生成功的标签和幸福的象征,进而在实际的生产生活中无所顾忌,毫无节制地消耗物质财富和自然资源,并通过
浙江省是目前全国唯一获批开展国家标准化综合改革试点工作的省份。()
根据《党政机关公文处理工作条例》的相关规定,民族自治地方的公文,()。
自卑的人常常有着强烈的防卫心理,主要表现在()
SQL查询语句中,将查询结果存放在永久表中应使用短语
Soonafterstartinghisjobassuperintendent(监管人)oftheMemphis,Tenn.,publicschools,KrinerCashorderedanassessmentofhi
最新回复
(
0
)