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
42
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.Killing Power of Ancient Volcanic Eruptions
B.Association of Mass Extinctions with Volcanic
C.Calculation of the Killing Power of Older Eruptions
D.A Mass Extinction
E.Volcanic Eruptions That Caused No Mass Extinction
F.Accounting for the Killing Power of Older Eruptions
选项
答案
B
解析
第二段的第一句话是这么说的:Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions.利兹大学的Paul Wignall正在研究火山爆发与物种大量灭绝的联系。the association of mass extinctions with volcanic eruptions与the link between voleanic eruptions and mass extinctions在意思上是相同的。
转载请注明原文地址:https://kaotiyun.com/show/zCGd777K
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
SaveEnergyatHomeOntheaverage,Americanswasteasmuchenergyastwo-thirdsoftheworld’spopulationconsumes.That’s
Accordingtothepassage,inbuyingasecond-handvehicleitismostimportanttoknow______.AccordingtoBleakly,beforebuy
TreesTreesareusefultomaninthreeveryimportantways:theyprovidehimwithwoodandotherproducts;theygivehimshade;
TreesTreesareusefultomaninthreeveryimportantways:theyprovidehimwithwoodandotherproducts;theygivehimshade;
TheTelevisionCameraThetelevisioncameraisratherlikethehumaneye.Boththeeyeandthecamerahavealens,andboth
LivewithComputerAftertoolongonthenet,evenaphonecallcanbeashock.Myboyfriend’sLiverpudlian(利物浦的)accentsu
TheValueofMotherhoodInshoppingmalls,theassistantstrytopushyouintobuying"agifttothankherforherunselfish
TheValueofMotherhoodInshoppingmalls,theassistantstrytopushyouintobuying"agifttothankherforherunselfish
ScienceandTruth"FINAGLE"(欺骗)isnotawordthatmostpeopleassociatewithscience,Onereasonisthattheimageofthes
Theygotinquiteabrawl.
随机试题
亚里士多德说:“我们由于从事建筑而变成建筑师,由于奏竖琴而变成竖琴演奏者。同样,由于实行公正而变为公正的人,由于实行节制和勇敢而变为节制的、勇敢的人。”这表达了在进行道德修养时,应该
为减轻肾病综合征病人长期服用肾上腺皮质激素的副作用,可采用下列哪项方法
下列关于水射流切割说法正确的有()。
某企业从设备租赁公司租借一台价格为100万元的设备,总租金和寿命期均为36个月,每月初支付租金,年名义利率为12%,则月租金为()万元。
连续梁、板的受力特点:是()。
西方心理学家马斯洛认为人类的需求可分为五个层次,由低到高依次为()。
ItraveltotheBinhaiNewAreabylightrailwayeveryday,______domanybusinessmenwholiveindowntownTianjin.
面对不断出现的消费和产业成长热点,企业的注意力应首先放在寻求高成长产业的“先进入”_______上,以_______供不应求阶段的高额利润。而当进入者不断增加,竞争加剧后,企业则应将重点放在低成本为_______的价格竞争上,以保住和扩大市场份额。填入画横
若圆(x-3)2+(y+5)2=r2上有且只有两个点到直线4x-3y=2的距离等于1,则半径r取值范围是().
Anorganization’sreputation,profitability,andevenitscontinuedexistencecandependonthedegreetowhichitstargetedpub
最新回复
(
0
)