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
Older Volcanic Eruptions Volcanoes were more destructive in ancient history, not because they were bigger, but because the c
Older Volcanic Eruptions Volcanoes were more destructive in ancient history, not because they were bigger, but because the c
admin
2014-05-13
57
问题
Older Volcanic Eruptions
Volcanoes were more destructive in ancient history, not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease.
Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large numbers of animals, but all the mass extinctions over 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. He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava(熔岩)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.
The Permian(二叠纪)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(十亿吨)of carbon as carbon dioxide. The global warming that followed wiped out 80 percent of all marine genera(种类)at the time, and it took 5 million years for the planet to recover. Yet 60 million years ago, 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 65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid(小行星). He thinks that older volcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO
2
. 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. He 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 emissions.
What is Vincent Courtillot’ s attitude toward Wignall’ s idea?
选项
A、Positive.
B、Negative.
C、Neutral.
D、Unclear.
答案
B
解析
最后一段表明了Vincent Courtillot的观点,根据最后一段第一句可知,他认为Wignall的观点具有争议性,因此他对Wignall的观点是持否定态度的。provocative挑衅的,煽动性的,激起争端的。
转载请注明原文地址:https://kaotiyun.com/show/UdQd777K
本试题收录于:
职称英语理工类B级题库职称英语分类
0
职称英语理工类B级
职称英语
相关试题推荐
Parkinson’sDisease1.Parkinson’sdiseaseaffectsthewayyoumove.Ithappenswhenthereisaproblemwithcertainnervec
Becauseadministeringthewholecompany,hesometimeshastoworkaroundtheclock.
A.imaginativelyB.recentlyC.carefullyD.unscientificallyE.accidentallyF.satisfactorilySchaeferfoundawayofhowto
One-thirdofParentsLackFactsaboutChildDevelopmentOne-thirdofparentsofbabieshaveasurprisinglylowknowledgeof
FactsaboutStroke1Every45seconds,someoneinAmericahasastroke.Every3.1minutes,someonediesofone.Strokekilleda
FactsaboutStroke1Every45seconds,someoneinAmericahasastroke.Every3.1minutes,someonediesofone.Strokekilleda
Sleepproblemscanseriouslyaffectone’squalityoflife.ActionswillsoonbetakeninAmericatobetterhelppeoplewithSle
DebateovertheUseofRenewableEnergyAmusableofRockefellerUniversityinNewYork,USsaysthekeyrenewable(可再生的)ene
Theyscatteredafterdinner.
TheGreatestMysteryofWhalesThewhaleisawarm-blooded,air-breathinganimal,givingbirthtoitsyoungalive,suckingt
随机试题
甲于6月2日将照相机借给乙,乙于6月8日提出以1000元购买该照相机,甲于6月9日表示同意,双方约定6月12日付款。乙取得照相机所有权的时间是【】
关于抗凝血酶Ⅲ的叙述错误的是
血尿多见于泌尿系统的炎症、结核、结石及肿瘤等,亦可见于血小板减少性紫癜等出血性疾病。
为提高出口货物在国际市场上的竞争能力,世界各国一般对本国实行()制度。
普通支票可以用于支取现金,也可以用于转账。()
—DoesAlanlikehamburgers?—Yes.Somuch______thatheeatsthemalmosteveryday.
组织战略规划和信息系统战略规划的关系是______。
略。
A、Tellpeoplehowtosucceedinacademicworld.B、Collectsongsinspiredbyworldfamousliteratureworks.C、Introducehowtoge
A、Babiesbegintolearnat5or6monthsold.B、Babiesbegintolearnwhenthey’reborn.C、Babiesdon’tliketobetaughtbystr
最新回复
(
0
)